The Gent's 'Pulsynetic' Waiting Train Electric Turret Clock Movement.

WT C40A on eBay

2011-05-31T21:31:00.016+02:00

VINTAGE TURRET CLOCK on eBay (end time 09-Jun-11 20:05:10 BST)

An early, Gents' Pulsynetic WT, in a rather sorry state, has turned up on eBay. The pictures are almost as poor as the condition of the early movement. I have enlarged them considerably and played with contrast and gamma for posting here.

The armature impulse hook is pre-roller suggesting a very early example of the small WT. Certainly pre-WW2 and perhaps even 1920s. The black, cotton (or silk) wrapped, insulated copper wire on the electromagnet bobbins is early too. (Though the wire insulating wrapping may have been dyed green originally) The relay electromagnet's bearing plate is diagonal and has chamfered ends. (though not easy to see here)

The original black (semi-matt) paint on the mainframe is an early indication. As is the rounded "knee" to the cast main frame above the drive electromagnets. The contact assembly support post is oval, fixed and horizontal in the major axis. Even slightly later iterations of the WT have a slotted support base and a taller vertical axis with radiused ends. All these details point to confirmation of its authenticity as a very early C40A WT movement.

Sadly the movement is still too distant to make out any real detail in the auction images. Enlarging even the original images just makes them fuzzy.

It looks as if the gathering pawl is absent but I can't be absolutely sure. It may still be attached to the pendulum top. Though it looks considerably slimmer than on later models.

It looks as if all the bevel gear cluster is missing at the rear. The usual casting to support the bevel wheels is present but there are no bevel wheels present. Nor their stub axle block. Not in any of these images. Though the wormwheel shaft must be present because a leading-off coupling is visible at the left of the movement. So at least you have a drive to one or two dials.

The worm could be badly rusted but it is impossible to see such fine detail from these images.The Hipp toggle and contacts are thankfully present. As is the WT relay coil and mechanism. The wiring almost certainly needs sympathetic replacement. It should run happily on 20 Volts DC when it is finally restored. You will also need a master clock, of course. These WT movements don't keep time (at all) without a master clock to give a correcting impulse at half minute intervals.

General view. The pendulum is present with top bearings still attached. Hopefully, that may well be the gathering pawl still attached to the pendulum too. (hanging at 45 degrees or 20-to-two) Though it is very difficult to confirm this from the image. The gathering pallet is a complex brass or bronze casting and not at all easy to reproduce without a machine shop. It straddles the pendulum rod and is also pivoted there. So this may have saved it from becoming lost. If only the images were better with decent close-ups!

This is very definitely not a restoration project for a complete beginner. Dismantling a rusty movement can easily damage vital parts. Clamping the movement in the vice would be cruelty beyond belief! Clearing vital threads in rusty holes requires the correct tools (taps) and some manual skill.

If screws are rusted in (and they very probably are in this case) then you can't just spray WD40 all over the place. It is a poor substance to use for this purpose anyway and highly toxic to some people. If I get so much as a whiff of it (even out of doors) I am ill for days!

There are much better (proper) penetrating fluids used by car mechanics and restorers. Browsing will throw up suggestions which may be locally available.

Patience is absolutely essential to allow the fluid to penetrate the rusty thread around the firmly stuck screws. There is very little room and the thread's normal air space is full of binding rust! Apply the proper penetrating fluid to all the screws at least a week before you even think about removing any of them. The longer your leave the fluid the better the chance of success. And, the least chance of a disaster!

Many of the fixing screws are cheese head, slot-head steel. Requiring the slot be cleaned carefully before a perfectly fitting, straight bladed screwdriver, of high quality, is applied. A worn or tapered screwdriver point will ruin your chances of removing the screw. A screwdriver which fits perfectly wíll seem almost too big but must reach to the bottom the slot in the screw head to ensure maximum turning force can be applied. Buy a brand new, quality screwdriver with a good handle for applying plenty of torque.

Cheap, or discount, tools will not have the highest quality steel of the best tools. Some Chinese tools are even made of mild steel! Which is absolutely hopeless. I have seen such screwdrivers take on a twist after a short period of use. Stanley used to be a name to trust but the last cross-head screwdriver I bought crumbled on the very first screw. Another Stanley cross-head screwdriver, which I bought well over four decades ago still works as if it were brand new.

Try screwing gently inwards before outwards. Try tapping the screw head with a very small hammer to break any remaining hold the rust may have on the screw threads. If the screw will not turn then apply more penetrating fluid and try again after a few days. Heat is sometimes suggested but may ruin the original paintwork. Unless you use a powerful soldering iron rested on the head of the screw.

Attempting to unscrew a rusted-in screw may snap it off right inside the casting. Now what? You will have to carefully centre punch the broken screw very accurately. Then drill it out a concentric hole with increasingly, larger drills. Without damaging the original thread in the casting. Now you have to remove the thin, tubular shell of the weakened carcase of the screw. A reverse threaded conical stud extractor helps here. Then you have to clean the rust out of the threaded hole with the correct tap. Without making the screw hole too loose for a new screw. No easy task!

If you haven't worked on old cars, old motorcycles or rusty bikes then don't start practising on an early Gents' Waiting Train. A tin of 3-in-1 oil and a pair of old pliers isn't going to get you anywhere! You may damage the movement beyond economical repair. Great patience is required in such a project or you may ruin the original finish on parts. Or break them while trying to slide rusty shafts through bronze bearings. The rust must be carefully removed first. If you think that rust removal involves a spinning wire brush in an electric drill then you may be in for a shock when it comes to valuing your finished project.

Plenty of motion work here! Leading-off rods and contrate gears. (A simpler form of bevel gear) The four sets of motion work have minute hand counterbalance weights. Condition mainly rusty and corroded. Most of it looks as if it has all been standing in the rain for years!

The pendulum impulse coil bobbins look as if they have disintegrated. This requires real skill and patience to fix properly. Because it probably means making completely new bobbins and a complete coil rewind. If you want to retain any semblance of originality you can't just rewind the coils with new enamelled copper wire. It will look completely incongruous! Greatly reducing the value of the movement. The coils will be by far the most difficult part of the restoration. Probably requiring a decent lathe at the very least. It may be just possible to glue turned new bobbin ends to the original cores without disturbing the windings. Though it would require considerable luck and skill.

Another view showing partially dismantled movement and all the dial work. One dial hour pipe (in the foreground) is rusted right away! As it came from a stately home the turret clock system may have been abandoned at some point in its history. It could be somewhere around 90-years old by now.

As so few of these WT movements come up on eBay it is very tempting to bid with your heart instead of your head. You may be desperately hoping the poor condition means it will be more affordable. I would suggest that, unless you have the proper skills, or know a man who does, you leave this one well alone. It would be better to save up and buy one in much better condition. Knowing what is involved I would hesitate to take this one on myself.

I hope the auction winner has the skills to sympathetically return this movement to its former glory. It is almost certainly the earliest WT I have seen in this size. If its installation history can be confirmed it will almost certainly add to the pleasure of ownership.

The auction ended on £1420 GBP.

Click on any image for an enlargement. Back click to return to the text.

Centenary of the Royal Liver Building WT

2011-04-21T22:40:00.336+02:00

This blog chapter is in celebration of the centenary of the Royal Liver Building WT clock installation. Not to mention the timely publication of Colin Reynolds' fascinating record of its construction. These were the largest electrically driven clock dials in the world when installed in 1911. Colin Reynolds' book covers the story of its construction from within the Gent company. With many unique, original illustrations and photographs from the time. Bringing the entire clock installation to life despite the intervening century.

Colin Reynolds' excellent book detailing the construction and installation is available from Formby-clocks or from Reprint.

Books on Church or Turret clocks - Jeffrey Formby Antiques

The Great George Liver Clock : Reprint

Gent enjoyed considerable, global publicity from the prestige of providing such a record breaking installation. Particularly for their newsworthy meal for 40 dignitaries around one of the completed dials. This led to WTs, for public dials, being sold right around the world. No doubt the sales of their impulse clocks systems increased as a result. WTs could be added to any impulse clock system. Often without the necessity for the special architectural details always needed by weight driven clocks. Not least finding room for the weight chutes.

This image us taken from an old book on aspects of electrical engineering. I scanned the illustration into my computer and then lightened it and improved contrast.

The WT was a truly revolutionary public clock movement. Providing a compact, reliable and incredibly accurate performance independent of weather conditions. Moreover it did not need arduous, regular winding or bulky weight shafts to house massive weights. Nor was it subject to the wear and breakdowns to which the far more complex, weight driven clocks were prone. Thanks to its relative simplicity a WT did not require a skilled turret clock maker to maintain it. This made it particularly attractive in undeveloped countries. Even haphazard mains electricity supplies were no real hindrance. Because the impulse clock systems and WT movement usually ran on trickle-charged batteries. Allowing the WT system to cope with power cuts.

Click on any image for an enlargement. Back click to return to the text.

Four, highly exposed, 25' dials are mounted 220' above the ground on two towers of the Royal Liver Friendly Society building in Liverpool. Three dials are mounted on one tower facing the sea and up and down the Mersey. With a fourth dial on another tower facing the city. The hands on each dial are driven by a single, large, Gents' Waiting Train movement. (tower image borrowed from Wikipedia) A Liver Bird surmounts each tower like a perfectly proportioned clock finial.

Royal Liver Building - Wikipedia, the free encyclopedia

These large WT movements were designed and hand built specifically to drive the hands of these enormous dials. Bigger, even, than the dials of the Westminster Clock which strikes the hours on Big Ben. The loads were made worse, on the Liverpool clock dials, by their exposure to Atlantic gales. Loads on exposed clock hands increase as the cube of wind velocity.

No practical mechanical clock could ever cope with such a task. Many unique problems were overcome in the manufacture and supply of the complete clock installation including the dials.

Accuracy, reliability and long life were essential. The WT is renowned for its accuracy under the most appalling weather conditions. Being also, and quite uniquely for a turret clock, as accurate as the master clock which controls it. With enormous reserves of torque to cope with icing and fierce, storm force winds on the giant hands.

Here is a view of just one of the four WT movements and the dial motionwork beyond. They are each mounted in separate, glazed, iron framed cases. These keep the mechanisms clean and avoids accidents to the unwary. The cases also provides unprecedented visibility of the clockwork mechanisms for visitors.

A view behind one of the 25'6" diameter, iron and opal glass, skeleton dials. The hour pipe can be seen supported on a massive cantilevered bracket. Due to the enormous loads, on the slowly rotating components, Gent's engineers came up with a unique system of rollers. The hour pipe itself is supported and restrained against lifting by three outboard rollers. The minute arbor is itself supported on rollers attached to the hour pipe. The huge bracket, cantilevered off the building's masonry, supports the roller bearings for the clock hands close behind the dial.

The darker roller assembly can be seen at the centre of the huge dial in the image above. Plain bearings would have had far too much friction and potential corrosion problems over time. Particularly in a maritime environment. While the rollers have provided reliable, low fiction bearings for 100 years.

The many tie rods and turn-buckles can be seen holding the cast framework of the huge dials onto the inner masonry of the tower. Lighting is provided so that the dials can be seen and read from a great distance at night. This stand-off dial design allows the tower to be closed behind the dial. Otherwise a huge hole would have been necessary right through each face of the tower to allow the dials to be evenly lit at night.

A general view of one of the WT movements. The large electromagnets (protectively wrapped in red) provide the driving impulse to the massive pendulum. The electromagnets are switched on via a Hipp toggle and electrical contacts. Smaller electromagnets lock the electrical contacts closed to provide an extended impulse. At the end of the swing a pin on the crutch unlocks the contacts again.

The main frame is diagonally braced against twisting. Resisting the reaction forces of the giant wormwheel as it drives the exposed hands. Frame bracing, in depth, is provided for the massive pendulum. A brass, hand setting dial is provided on the free end of the wormwheel shaft. The, long, bright steel, horizontal shaft near the bottom of the movement frame is the worm arbor (or shaft).

A close-up of the Hipp toggle and block. Instead of a single Hipp V-block a multi-toothed rack is provided here. Perhaps as extra insurance against slipping or missed impulses. It may also allow a smaller pendulum arc for emergencies in very bad weather.

The freely pivoted, Hipp toggle (hanging from its bracket at top left) looks no different from that on my own relatively tiny WT. Almost hidden below the Hipp block and contacts are the contact locking electromagnets. Also wrapped in red, protective material. Just like the larger drive electromagnets.

The Hipp toggle and its block form a simple, but totally reliable, electro-mechanical switch. Together, these apparently simple components constantly monitor the pendulum arc. Only giving a drive boost (via the large drive electromagnets) if the pendulum arc falls below the set limit.

Normally the toggle rattles freely back and forth across its block. Only when the pendulum swing drops low enough will the toggle catch in the block on the return swing. The toggle then depresses the block and firmly closes the attached electrical contacts. Electricity flows through the large drive electromagnets. Giving the pendulum a really strong push.

If the clock hands are struggling to overcome heavy winds the pendulum swing will drop more quickly due to the extra energy demanded. The toggle will close the contacts as often as required to maintain the pendulum's minimum arc. As often as every other swing if necessary.

So many extra drive impulses provide a massive increase in power and torque to drive the hands in poor weather conditions. When the storm has passed the toggle senses the lighter load and the impulses become very much less frequent. It was the combination of Hipp toggle and the (completely automatic) variable frequency of drive impulsing which made the WT so utterly reliable. Many weight driven clocks would run slow or even stop in very bad weather.

To the right of the toggle is the (black) pendulum impulse hook cast onto the crutch. The impulse from a roller takes place on top rather than underneath the hook. (the latter usually occurs on the smaller WTs) This detail is rather difficult to see because of the enclosing casting.

The WT movement with the large, 30-tooth ratchet wheel in the foreground. The ratchet wheel converts the oscillating motion of the pendulum into rotational movement. On smaller WTs the ratchet wheel has only half as many teeth as the Liver clock movements. Presumably the engineers decided that a larger wheel would need huge teeth if limited to only 15 teeth. Which could not possibly be gathered securely by the pawl. Not unless the ratchet wheel and its pawl were placed very low on the pendulum rod. (or on a much longer crutch)

Having two, D-shaped, lifting pins on a much larger ratchet wheel, with finer teeth, satisfied several vital geometrical requirements. The finite swing of the pendulum and the distance down from the pivot bearings provides a strictly limited stroke. The Liver movement ratchet wheel makes one complete rotation in slightly less than one minute. The teeth are large enough to be physically reliable. Without requiring an excessive swing of the pendulum to gather its teeth. Most of the critical components on the WT are made of gun metal. A tough, hard, wear and salt resistant bronze. Brass would corrode over time.

Beyond the ratchet wheel, on the same shaft, is the worm. The worm and its matching wormwheel must provide a 60:1 reduction in rotational speed and a similar increase in torque. The bottom half of the wormwheel is seen edge-on near centre top of the image above. Presumably it uses a double start worm to achieve a 60:1 reduction from the worm shaft. The wormwheel must rotate once per hour to provide the minute hand drive without extra complication in the motionwork gear ratios.

Note the heavy thrust bearings to resist the severe end-loads on the worm. The worm not only drives its wormwheel against the loads on the giant clock hands outside the building. It also locks the hands safely against any unwanted movement. Perhaps due to ice imbalances, flocks of birds on the clock hands or wind loading. Backlash would be very undesirable because it would show timekeeping inaccuracies on the minute hands of each separate dial.

Interestingly, it was the inability to limit variations between dials which excluded the use of four separate weight driven, turret clock movements. Gents were able to offer a guarantee that all the dials would show the same time thanks to their master clock control. The contract to build the Liver Clock installation stipulated 2 seconds per week accuracy. Few turret clocks can manage this.

Detail of the pendulum support bearings. A fine ratchet wheel is provided on the end of the bearing support shaft. This provides slow rotation of the bearings to avoid flat spots on the bearing races. The loads on the pendulum bearings are always predominantly downwards.

On smaller WTs a hand wheel is provided, just here, to allow random rotation of the ball races. Presumably the friction would be too great in a WT of this massive scale to turn a knob by hand. The Gent engineers have cleverly provide auto-rotation. So nobody needs to worry about forgetting to turn the knob at intervals.

Pendulum top and bearing assembly from the other side. The cylindrical, black-painted counterweight of the gathering pawl and the pawl bearing can be seen centre right. The black bar hanging almost against the main frame is the pendulum crutch. Oiler caps can be seen on the pendulum bearings. The fine ratchet wheel (bearing rotator) is well seen here. The bearing shaft, ratchet pawl is rocked between adjustable stops by the swinging pendulum.

Here I have labelled the major components of a Liver WT movement. (Just in case you have become lost in my wordy descriptions) Click the image to enlarge it for greater detail. Back click to return to the text.

BTW: I have used both ratchet and gathering wheel interchangeably for the same component.

The "WT magnet" labelled on the left is a small "relay" electromagnet. (Wrapped in black) Connected in series with the master clock it releases the (momentarily locked) WT drive to the hands once every half minute. The rest of the time the hands advance perfectly normally.

This incredibly simple mechanism, is used in a design of pure electro-mechanical genius. It forces the giant hands of the dial to follow the master clock exactly. Maintaining an accuracy to within a couple of seconds per week. The pendulum becomes a powerful and totally reliable electric motor. The WT mechanism harnesses this enormous power to keep perfect time.

The actual Waiting Train mechanism in close-up. The 30 tooth ratchet wheel is pulled around by the swinging pendulum via the gathering pawl. (the black horizontal lever in the centre of the image) Twice every revolution of the ratchet wheel one of two D-shaped pins lifts the L-shaped lever. This lever is counterbalanced and pivoted in the relay electromagnet pivot plates on the left. A backstop (lever) resting in the teeth of the ratchet wheel stops the gathering wheel from turning backwards.

Driven by the gathering pawl, the L-shaped lever lifts until it has been locked by a step in the relay electromagnet's armature. Now the gathering pawl can no longer reach the teeth of the wheel. A forward projecting pin, on the pawl, slides freely back and forth on top of the L-shaped lever. (without the pawl able to gather more teeth on the ratchet wheel)

Moments later the short electrical impulse comes through from the master clock. The armature is instantly attracted to the relay electromagnet core. Releasing the L-shaped lever. The L-shaped lever drops. The gathering pawl can now drop back into the teeth of the ratchet wheel and immediately starts driving the hands normally. The short pause in drive to the hands goes completely unnoticed by anybody viewing the clock dials. While the drive is interrupted the worm and wheel keep the clock hands safely locked.

The Gents' Waiting Train mechanism now seems almost blindingly obvious. Until its invention there was no way to synchronise a large and powerful public clock with a precision master clock. The greatest acts of mechanical genius often seem incredibly simple with our perfect hindsight. Yet, before its invention the problem was seemingly insurmountable.

The brilliant Gent engineer, A.E.J. Ball, was the genius who provided the solution. One which totally revolutionised public timekeeping. Clock dials, driven by WT movements, could now be easily fitted into slender war memorials and industrial chimneys alike. There was no longer any need to provide easy access to clock winders and minders.

Only the arrival of the Warren synchronous electric motor finally beat the WT for compactness. The synchronous motor driven, public clock dial was several decades away when the Liver building clock system was installed in 1911.

The coupling between the WT and its dial motionwork (in the case on the left) takes the form of a gimbal. This allows for slight variations in alignment between the two mechanisms without binding. The inner set of rollers, for the hour pipe, are seen on the extreme left inside the glass case. The inner, minute hand shaft rollers are on the right of the large gear wheel in the centre of the case.

The motionwork provides the usual 12:1 ratio between the minute and hour hands. Normally the motionwork is fitted just behind the dial. In this case the loads on the giant hands are so high that an inboard motionwork is provided for each dial. The motionwork supports the inner end of the hour pipe on solid masonry. The cantilever bracket, behind the dial, supports the outer end. The great length between the bearings provides extra stability and distributes the loads more evenly.

A closer view of the dial motionwork. The 12:1 reduction is provided by two reduction pairs of gears. Only two gear wheels and two pinions are required. Albeit unusually large ones in this case. Only the sheer scale of the wheels and supporting castings gives an impression of the huge size of the hands and dials involved.

The minute hand counterweight rotates once per hour between the WT movement and its motionwork.

Another chance to admire the genius of this unique tower clock movement. Its apparent complexity merely disguises precisely the same functions as those of the smallest WTs. The top of the massive pendulum bob can be seen at the bottom of the picture. The crutch is provided with two pins which straddle the pendulum rod. This is standard clock practice and ensures the crutch closely follows the pendulum. Providing solid drive and accurate location of timed events relative to each other.

An alternative view showing details not easily seen from other viewpoints. The contact device in the foreground, on top of the frame, is related to the extended drive impulse. The long, hooked arm is released by a pin on the crutch at the end of the extended, pendulum, drive impulse.

I am most grateful to Colin Reynolds, author and ex-managing director of Gents for sharing this information. He was also able to confirm the presence of two D-shaped, lifting pins and even provided a diagram of the electromagnetic locking of the extended impulse mechanism. Original images of the WT can be found in his book shown at the top of this page.

Click on any image for an enlargement. Back click to return to the text.

WT Time setting handle balance weight

2011-03-30T18:05:00.002+02:00

When a WT is running without any load it often happens that the time setting handle flops forwards to the bottom of its travel. Though the WT movement still performs perfectly there is a quite a long delay before the resetting impulse arrives. The long delay is irritating to the interested observer. Who is usually waiting patiently for each tooth of the ratchet wheel to be gathered. So that the D-shaped pin finally lifts the gathering pawl out of the escape wheel teeth. Thus performing the vital "Waiting Train" action.

This "hic-cup" in normal operations is due to the unbalanced weight of the time setting handle and a lack of friction in the worm shaft.

I have discovered a very simple way to overcome the handle flopping forwards. One which requires no more than a pair of pliers and an ordinary British, mains plug, earth pin.

Remove the fixing nut from the D-shaped pin at the back of the ratchet wheel. Now replace the nut with the earth pin from your British mains plug. Tighten the earth pin gently onto the thread of the D-shaped pin with the pliers. The threads match perfectly on my own WT.

Now loosen and point the time setting handle away from the D-shaped pin before re-tightening onto the end of the worm shaft.

IMPORTANT: Now turn the time setting handle gently a few times. Just to ensure there are no obstructions to the plug earth pin on its circular travels between the ratchet wheel and worm. If you let the WT run with an obstruction it is so powerful that it may break something vital!

The earth pin counterweight will achieve sufficient balance to avoid the handle flopping forwards.

This simple balancing trick is ideal for the collector who has a WT running lightly. With no large clock hands, lead-off work or bevel gears to drive. It will ensure each tooth of the ratchet wheel is gathered properly. The irritating flopping forwards of the time-setting handle will no longer occur. Which is very handy for the obsessive maker of WT videos and the avid clock watcher.

The really fastidious may like to make a suitable counterweight which can be completely hidden behind the ratchet wheel. An old, UK 15A plug has a round earth pin probably more massive than the square pin type. A short length of brass rod with a suitable threaded hole might suit. Or even a more dense material than brass.

Just ensure that no obstruction can possibly occur between the counterweight and the WT movement.

Keep the original D-shaped pin fixing nut somewhere safe in a polythene bag or pot. You may need it one day.

Click on any image for an enlargement. Back click to return to the text.

Introduction

2008-08-30T09:03:00.057+02:00

This blog is a very simple, illustrated "How it works" description of the Gent's Pulsynetic Waiting Train Turret Clock movement. As this is such a mouthful I have used the acronym 'WT' throughout the text.

The Gents' Waiting Train Movement.

(Photographed before small missing details were added)

I have now added later "chapters" with illustrations and descriptions of some other common items used in the Gent's "Pulsynetic" impulse clock systems.

This blog is certainly not intended as a learned history. I simply wanted to share my admiration for this revolutionary, public clock movement. And, also its associated electric impulse clock system.

There was so little information publicly available on the WT movement that I decided to help to correct this lack myself. Hopefully the information found here might allow a WT to continue in service. Or avoid it being permanently damaged by being plugged directly and catastrophically into the mains electricity!

If you don't want to read my rambling text then why not just enjoy the pictures? Left clicking on any image will result in a larger picture. Back click to return to the text.

Simultaneously pressing Ctrl+ or Ctrl - will change the size of the text in many computer browsers. Pressing Ctrl O (zero) will return the text to its normal size. I have deliberately chosen quite a large text size. This can easily be reduced with Ctrl-.

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My Gent's Model 'C40A' Waiting Train turret clock Movement No.309 was built somewhere around 1939. The WT (as it is affectionately known) is my favourite type of clock movement. It enjoys the benefits of reasonable size, large and small electromagnets, deep gold lacquered brass parts and finely-cut gears. All built into a beautiful whole thanks to its elegant cast frame. Where form not only follows function but has the gift of its own unique beauty. One might even suggest that art nouveau influences are seen in its organic, flowing lines. The period when the WT was being designed and developed lay precisely during the height of the Art Nouveau movement.

The large pendulum drive electromagnets

I first discovered the Gent's Waiting Train in an old book in the local reference library as a schoolboy and was fascinated by the illustrations. I would never have believed that 40 years later I would actually own one myself. I do hope you find something of interest here and will share my enthusiasm for this unusual tower (or turret) clock movement. (the terms are interchangeable) I make no apologies for the repetition required for clarity in each of the "chapters" which follow.

While I have tried to use the correct horological nomenclature to describe the fine details. I am almost sure there are places where I have lapsed to more everyday names. You can't please all of the people all of the time. I return here at rather irregular intervals to read through my text. Looking for spelling mistakes and better ways of expressing things. New images (or videos) are added quite regularly. I doubt a week passed without my making some change or addition as something new occurred to me. Don't be afraid to "refresh" or clear your cache and start reading from the beginning if you feel so inclined.

Please feel free to share any images or information you might have on WT's or their installations. Images would be very much appreciated if you have them. I hope you will enjoy discovering the details of this unique movement as much as I have enjoyed putting this information together. If you find anything you don't agree with then do let me know. I am a humble clock enthusiast not a horological historian nor a professional writer. I will openly welcome constructive criticism about anything you see here. Though you will have to register to be able to leave comments.

The WT movement seen from the back.

Most turret (or tower) clocks are driven by very heavy weights hanging from long ropes or wire cables wrapped around winding drums. Often pulleys were used with even more massive weights to achieve a longer run time or smaller drop. These massive weights were often a nuisance because they required so much room in the spaces below the clock chamber. Sometimes the weights were allowed to descend into long wooden chutes to reduce the danger to those below should a rope or cable break. This was not an unknown occurrence and sandbags were often placed at the bottom of weight shafts to break their fall!

Moreover, the weights had to be wound up regularly or the clock would simply stop. This might sound rather trivial but in practice turret clock movements were set high up in very cramped and inaccessible spaces. The clock keeper had to climb up to the clock, engage a large, cranked winding handle and then exert considerable effort in winding the massive clock weights back up again. This allowed the clock to run for a further period. The frequency of rewinding varied. Sometimes the clock needed to be wound every day, or at 30 hour intervals or only once a week. Only rarely would a turret clock run for much longer than a week. During the actual rewinding the clock would sometimes stop unless it had maintaining power to drive the clock escapement via the wheel train. This was usually supplied in the form of a weighted lever which engaged in the teeth of a suitable wheel in the gear train. No great accuracy was required provided enough rotational force (or torque) was supplied to keep the movement running.

It must be remembered that in former times the public clock dial was usually a vital timekeeper for a whole community. Watches were strictly for those who could afford them. It would be difficult to imagine the drudgery of keeping a clock rewound and to time if the keeper did not enjoy caring for the clock. Often the task was carried out by a volunteer or poorly paid church or estate worker. Rarely would the keeper have any real training in the skill of maintaining or oiling the movement. Nor taking care of the associated ropes, cables and multiple pulleys, lead off rods, couplings, bells, striking work or dial motion work.

I have visited an estate turret clock where the clock's winding handle could not even be rotated through a full circle because of the massive, badly-placed beams in the clock tower's construction. The torture and labour of winding such a clock is quite simply unimaginable today! It was impossible to stand upright. Yet too high to reach when kneeling down! So a half crouched position with one's hands held just above one's head was required. The effort of simply turning the handle by half a turn was downright unpleasant! It is no wonder that this particular clock had not been rewound in over 30 years and the clock chamber was ankle-deep in fallen plaster and other debris. Other clocks were reached in very high towers via tall and flimsy ladders. Sometimes requiring squeezing though tiny trapdoors before ascending the next seemingly endless ladder into the complete darkness high above. It seems that Health and Safety at Work is quite a modern concept! Many of these clocks had required regular winding for centuries!

Until, that is, the Gent's Waiting Train turret clock movement appeared. Like all simple ideas it was a work of true genius. It broke completely with most previous clockmaking traditions. The WT was very unusual for a pendulum turret clock in being driven by low voltage DC electricity and large electromagnets. Moreover it applied the power to the fast moving end of the gear train rather than the slow end. This unique arrangement greatly increased the power available to drive the hands of public clock dial(s) from such a remarkably compact movement. Added to this, the WT brought previously unheard of accuracy to public timekeeping.

The WT continued to tell the time to within a few seconds a week regardless of the weather conditions attacking the exposed clock hands outside the building. Many weight driven turret clocks stopped completely. Or became unreliable timekeepers in gales or wintry weather. The hands on public clock dials are usually counterbalanced. However, a build up of ice along the length of a hand could easily swamp any balancing weight. This out-of-balance would greatly increase the friction and torque required to lift it against gravity. Leading to serious timekeeping problems or actual stoppage. The WT's reserves of brute (but finely controlled) power could easily overcome these problems.

Errors in timekeeping with weight driven clocks had to be corrected manually with all the problems this caused in resetting the hands to the "correct" time. The dials were always invisible to the clock keeper inside the building. Though many, more modern movements, had a small hand setting dial older movement would not have this luxury. Who knows the accuracy of the watch used to reset the clock to time? Or the accuracy of the reference clock used to set the watch in the first place?

It would be amusing to imagine the watch being set to the hands of another, equally inaccurate, local turret clock before the advent of radio time signals. A so-called Zanzibar Fallacy could easily arise under these difficult circumstances. Where one clock keeper set his own clock to another public dial and then the other clock keeper would reset his own clock to match the first. Perhaps a local sun dial was normally used? In this case one must hope that the clock keeper was familiar with the Equation of Time.

http://en.wikipedia.org/wiki/Equation_of_time

The truly major breakthrough with the WT was the end to arduous rewinding. The lack of bulky weight shafts allowed the WT to be housed in tight situations where a weight driven clock would have been completely impossible to fit. Not to mention the greatly reduced need for easy access to the movement for rewinding. It is difficult to imagine the savings in manpower (and wages) from removing the human burden of clock rewinding. The WT was also infinitely more reliable than many older clocks. Many of which required the regular attentions of a clockmaker as is noted in many a church's financial records.

Early in the 20th century the largest public clock dials in the world were suddenly made possible by the WT design. The WT movement was available in several increasing sizes depending on the intended size and number of clock dials, their height above the ground and the degree of exposure to high winds. All sizes of WT offered the same remarkable accuracy, reliability and freedom from the attentions of the often-unskilled and possibly unhappy clock winder.

The WT began to be installed in all kinds of buildings and structures from the early 1900s onwards. They were used in railways stations, fire stations, office blocks, town halls, chimneys and churches and in many tall and slender war memorials worldwide.

Rather oddly, the WT was resisted in clock making circles as "new fangled" technology. Architects continued to stipulate outdated, weight driven movements for their prestigious new buildings. Clock making had a very long history and had developed such inertia that new ideas were not readily accepted. Or were sometimes bastardised into situations and movements where simpler methods were often far superior. For example: Many weight turret driven clocks and spring driven domestic clocks employed the dead beat escapement. Which was only superior in special cases where the driving force was very steady, constant and even. The blind adoption of the dead beat escapement for general use was rather typical of the clockmaking industry. As were major bottlenecks in the design of pendulums. These oddities went on for centuries due to blind ignorance amongst clock makers.

But enough of my opinionated rambling: Here are some seriously useful (free) guides for turret clock keepers, owners and those charged with their care and maintenance. Written by real experts with useful illustrations:

Regardless of the type of movement or its place of installation you should acquaint yourselves with the expert practical advice found in The "Turret Clock Keepers Handbook."

You could save a unique clock movement from rapid deterioration, major repair or an expensive overhaul simply by changing your own misguided activities concerning the clock in your charge. Or even save yourself and others from serious harm as a result of an unforeseen accident.

TCKH.pdf (application/pdf Object)

The second link is to a very comprehensive guide to detailed practical restoration and a guide to getting work done properly to safeguard the clock movement, dials, bells and installation for future generations.

Turret Clock Guidelines.pdf (application/pdf Object)

Click on any image for an enlargement. Back click to return to the text.

The WT Pendulum

2008-08-29T08:00:00.030+02:00

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Let's start the detailed look at the WT movement with the motive power behind its remarkable accuracy. It should be said right away that the WT's pendulum does not directly control the accuracy of timekeeping. In fact the WT pendulum does not even have any adjustment for length to change its timekeeping. Nor any compensation for changes in temperature. The incredible accuracy of the WT comes from half minute signals received from a remote, and quite separate, precision master clock.

The heavy cast iron bob (seen below) is actually cast onto a short, bolt-on extension of the pendulum rod. This simple, but clever idea allows the bob to be removed and packed separately from the WT movement while on its way to an installation. Thus saving potential damage to the movement over long journeys, perhaps even overseas. When work is required on the WT movement the bob can be freed in moments simply by by removing two bolts. This small but important detail is typical of Gent's remarkable skill in design and fabrication. The advantage over a simple hook on the pendulum is that theft becomes much more difficult without immediate access to a suitable spanner.

For the moment let's deal with the almost unstoppable power of the Waiting Train movement. Regardless of snow and ice on the hands outside the high clock tower the WT can always cope. It brushes off fierce winter gales without a problem. The secret lies in the Hipp toggle and its all-important, matching Hipp V-block.

The Hipp toggle is a chisel-shaped piece of brass pivoted freely about half way down the WT's pendulum. The toggle is carried back and forth across its notched V-block by the swinging pendulum. Normally the toggle passes freely over the block in both directions with a rather hypnotic rattle. For a clock fan the Hipp toggle is priceless therapy. One can watch for hours. Just waiting ... and waiting. Until, at between 20-60 second intervals, the Hipp Toggle can no longer fall free when passing over the Hipp Block. The arc of the pendulum has imperceptibly reduced to the point where the toggle can no longer clear its notched block.

Then, with a powerful downward thrust, provided by the inertia of the heavy pendulum, the toggle is forced deep into the notch in the block. This pushes the attached bronze contact blade downwards and closes the heavy electrical contacts.

Click on the images for a close-up of the Hipp Toggle, V-Block and contacts. I made the entire missing contact assembly myself to match images and drawing provided by fellow WT owners. The bent bars are silver soldered together from yellow brass strip. The originals were cast but I had no access to any spares.

I really should have lacquered them deep gold by now to match the other, original brass parts. The screws also need shortening and tidying up. The contacts were made from solid silver rod bought from a local jeweller and soft soldered to riveted brass bases. Obtaining the necessary bronze spring strips was difficult but the material were finally found in the non-ferrous scrap bin of a local factory. The insulation between the parts is mostly model maker's plastic sheet. The holes were bored oversize and model aeroplane, fuel tubing slid over the long screws to ensure electrical isolation of all the various parts.

The moment the contacts are closed the 20 Volts of DC (Direct Current) electricity streams through the thousands of turns of insulated copper wire in the large electromagnets. The electromagnetic power in the coils is transferred to the soft iron cores. Which then attract the rocking armature with great force. The armature has a broad roller at the top which rises. Pressing upwards under the cast extension on the pendulum rod just as it swings past.

Pendulum drive mechanism.

As the roller is forced to follow the curve on the corner of the cast hook it gives a push to the pendulum. Allowing it to continue swinging for another 20-60 seconds or even more. The method of pendulum drive impulsing is very similar to the gravity arm and roller impulse of many master clocks. Except that, instead of gravity, the impulse is applied upwards, in the WT, by the power of the drive electromagnets.

In this way the pendulum automatically calls on only enough power to manage the loads placed upon it. Just as a parent pushes a child on a swing only when the arc drops below a certain point and the child demands more height. Fortunately the WT does not get bored or tired and will continue pushing its pendulum for decades unless the electric power supply is interrupted.

Another view of the driver electromagnets, impulse corner and roller pallet.

Note how the under surface of the "hook" is curved to follow the radius from the pendulum's pivot. Such a "dead" surface is a common term in horology to describe the geometry of an escapement. Any pressure applied to this curved surface has no effect on the clock. (other than friction) It also avoids collisions between moving parts.

Under still conditions the pendulum may swing for up to a minute before taking another power impulse from the electromagnets. When, however, there is a roaring wind and ice forming on the exposed clock hands the loads on the movement increase enormously. Because of the increased resistance to rotation felt through the lead-off rods the pendulum loses its arc much more quickly. The moment the arc falls below the minimum set by the Hipp toggle the pendulum is rewarded with another push from the drive electromagnets via the armature, roller and impulse pallet.

As weather conditions improve the power impulses grow less and less often. When bad weather demands it the impulses can be as often as every other swing. An increase in power of up to 30 times, or more, compared with normal power impulsing.

Note the wax insulation on the electromagnet coils in the picture above. This was part of Gent's protection for the movement against the foul conditions often experienced by turret clocks. Notice the heavy build of all the parts to help the movement survive for many decades. Often under difficult environmental conditions abroad. Where skilled repairers were often completely absent. Gent's knew their market and built equipment to match the worst conditions imaginable. Despite the need for reliable function many of Gent's products still have an honest, workmanlike appearance. Gent's were were often at the leading edge of technical and materials use and development.

Here is an image of the hand wheel and pendulum support bearing housing at the top of the pendulum. This is another of Gent's breaks with tradition. The flat spring, which had supported pendulums of all kinds for centuries, is discarded in favour of sealed ball bearing races. This was a bold move and shows Gent's care in their designs. The completely enclosed bearings could be greased in the factory and then be relied upon for several decades without skilled attention. Being invisible, there was no temptation to add potentially damaging lubricants.

The main advantage was the lack of a fragile pendulum suspension spring. Which could be broken on the journey out to some distant site of installation. Or broken during clumsy installation by unskilled labourers. The twin ball bearings themselves are housed in the silver-coloured castings. The top of the pendulum is bifurcated to allow it it be supported equally either side of the bearing assembly. In warmer climes no doubt the grease would be better distributed than in cold northern environments.

The hand wheel has a very clear message on its face: Turning the handle occasionally, at random redistributes the grease and avoids localised wear on the concealed bearing races.

This image shows a lead-off rod, with universal joint, fitted into one of the four forked driver/expansion couplings on this WT movement. The lead-off rods eventually reach the backs of the clock dials. Where a similar forked coupling would join the motion work. (A simple reduction gearing of 12:1) The motion work gearing reduces the rotational speed of the minute hand from one revolution per hour to once every twelve hours. The hour (hand) is fixed to a pipe which surrounds the solid minute hand arbor. (or shaft) The direct drive from the lead off rods drives the minute hand. While the hour hand is driven at 1/12 the rotational speed by the motionwork gearing.

Lead-off rods can be of almost any length required to reach the clock dials. Abrupt changes of direction would be handled by bevel gears. This WT movement could drive the hands of four dials simultaneously. The simple universal, coupling joints are slotted to allow the lead-off rods to expand and contract with changing temperature without binding. Simple plain strap bearings were usually used to keep the lead-off rods in place. The longer the rods, the more twist in the system, over the length from the clock movement to the minute hand.

Where a clock refuses to run it is sometimes these simple metal to metal bearings which have dried up over time. A little oil may help if the strap bearing cannot be easily removed for cleaning and lubrication. Trying to push the lead-off rods lengthways in their bearings will sometimes indicate where they are sticking. The expansion joints should allow a bit of freedom along the length of the rod. So a stuck bearing will prevent this normal free play.

Click on any image for a larger version.

Back click to return to the text.

The Waiting Train Mechanism:

2008-08-28T11:24:00.032+02:00

(Left click for larger view. Back click to return to the text)

I have tried to use the terminology of this original Gent's diagram: Please refer to this drawing if in doubt as to the exact details and movement parts mentioned below.

The Waiting Train mechanism is a work of electro-mechanical genius in my humble opinion. Once understood, its mechanical simplicity defies belief. Yet it was a breakthrough which had eluded clock designers for centuries. While the whole movement is known as a WT only the top left part of the movement consists of the Waiting Train mechanism itself.

The WT pendulum working alone is nothing more than a powerful, low speed motor for driving public clock hands. It already had its advanced servo control constantly reading the mechanical resistance and fine adjusting the power input required. (thanks to the amazingly simple but brilliantly ingenious Hipp Toggle and V-block described in the last chapter)

The motor pendulum itself would cheerfully ignore all timekeeping duties if left to its own devices. Providing it was connected to its 20Volts DC power supply the pendulum would keep swinging and the clock hands would keep on turning. It would continue to do this regardless of weather conditions outside the tower affecting the slow rotation of the clock hands.

Unfortunately the timekeeping would be absolutely dreadful! Totally unusable as a public clock. Yet the WT movement is capable of keeping time to one second per week without any temperature compensation of its pendulum. Pendulum design had been a vexing problem for clockmakers for centuries but the WT did completely without temperature control. The secret of the WT's success lies in the Waiting Train Mechanism. This allows the WT movement to be remotely controlled to a very high degree of timekeeping accuracy by a separate, electric master clock.

Gent's master clocks were (and still are) widely used to supply accurate time signals. The signals were used for clocking-in workforces, process timing and recording, to sound factory sirens, bells and whistles amongst many other things. The master clock could drive literally hundreds of clock dials of all sizes throughout a factory, school or office block via a thin wire. Anywhere where uniform timekeeping was required a master clock could provide that service. No more arguments between workers and the wages office over variations of timekeeping between clocking-in machines and their own watches or clocks. Uniformity of timekeeping and accuracy of process control, recording of production tasks and machine running time were all closely controlled or recorded via the master clock at the heart of the timekeeping system.

Right up to the beginning of the 20th Century public timekeeping was in the hands of tens of thousands of weight driven, mechanical turret clocks. Many churches and public buildings housed clocks and had external dials. Many of these dated back centuries and their timekeeping had become notoriously bad in some cases. The need for accurate public timekeeping to aid the industrial revolution and mass production became absolutely vital. The railways needed accurate timekeeping or their passengers could never rely on published timetables. Something had to be done about public clocks and their often wayward timekeeping. Many wealthy industrialists and financial empire builders wanted large, accurate clocks on their buildings as mark of their status and power over their workforces and the world they served.

The upper limit on the size of mechanically driven dials had been found in great clocks like "Big Ben" the Westminster Palace clock. The difficulty of turning such enormous hands on very exposed dials on very high towers was a mechanical nightmare. Requiring enormously heavy weights and vast and expensive clock movements. Such clocks needed a lot of space for the great weights to fall as they drove the enormous movement. The hands on these huge clock dials were often at the mercy of the elements. Onshore gales, flocks of of gulls or pigeons and winter snow and ice would resist the slow movement of the huge, highly exposed clock hands. Often causing the clock to stop or to run slowly and erratically unless provided with an over-abundance of driving power. Moreover, these larger clocks often needed constant supervision and exhausting rewinding at all too regular intervals.

Captioned image of the WT movement:

(Left click for a much closer view. Back click to return to the text)

The WT's time setting crank and its wooden handle has been removed for clarity in this particular image.

Gent's answer to the serious problem of limits of scale and expense lay in the Waiting Train movement and its Waiting Train mechanism in particular. The WT had an enormously powerful motor pendulum. This could be scaled up to match almost any power requirements. Gent's designers still had to find a way of controlling the pendulum's timekeeping to a high degree of accuracy. So they designed an ingenious and totally reliable mechanism which is blindingly obvious and amazingly simple once examined and understood. The genius lay in the design of such a simple mechanism in the first place. They chose to interrupt the drive to the clock hands very briefly without interfering with the powerful pendulum motor or losing control of the clock hands. Then releasing the mechanical "brake" with a small electromagnet precisely on time.

The hands of the WT driven clock dial are always connected to the wormwheel. (via lead-off rods and bevel gears) Wormwheels are always locked against free rotation by their matching worm. A worm is rather like a threaded rod or machine screw which rests against and rotates in the wormwheel's matching teeth. One turn of the worm advances the WT wormwheel by one tooth. A worm and wormwheel is a torque multiplier with a matching large reduction ratio of rotation. Assuming a 120 tooth wormwheel and worm of perfect efficiency the torque is increased by 120x and the speed of rotation reduced by 120 times. This is an ideal ratio for a public clock movement needing considerable torque to turn and control the huge hands but also needing slow rotation to show the time.

The WT pendulum at 70cm effective length was designed to run faster than one which would keep perfect time over a half minute. On each swing to the right the pendulum drags the worm round via a strong 16 tooth ratchet-toothed escape wheel and heavy driving pawl. The ratchet (or escape) wheel makes one turn in 27-28 seconds and is fixed on the same shaft as the worm. The worm drives the wormwheel which drives the clock hands via the bevel gears and lead off rods.

Here is an image of the WT section during normal running. The D-shaped pin has just passed its lifting position. The electromagnet has been energised allowing the right angle lever to drop back to its normal position resting against its back stop. (presently covered in a length of black plastic tube which should ideally be replaced by an eccentric tubular backstop like the original)

The masking pawl has dropped out of the way. Allowing the driving pawl back into contact with the teeth of the escape wheel. The D-shaped pin will make a full revolution with the escape wheel before it arrives back at the position where it will again lift the masking pawl. (Left click for larger image. Back click to return to the text)

At about 27-28 second intervals the masking pawl is lifted by a D-shaped pin which is bolted to the escape wheel. A high tooth precedes the D-shaped pin ensuring the wheel is safely gathered as the lifting face begins to push upwards on the driving pawl. Once lifted, the driving pawl can only slide back and forth on the top surface of the masking pawl as the heavy gathering hook (pawl) can no longer reach the escape wheel teeth. The hands are still securely held by the wormwheel and worm. Which keep the hands safely locked against any imbalances caused by ice or uneven pressures from the wind. A right angle extension of the masking pawl is locked into a step in the relay electromagnet's armature.

Here is the locked and lifted position of the WT mechanism. The right angle lever is locked in the step of the relay electromagnet's armature. The driving pawl slides helplessly back and forth on top of the masking pawl unable to reach the teeth of the escape wheel. The high tooth above the D-shaped pin has allowed the driving pawl to pull the wheel to the locked position. Without the high tooth the driving pawl might not be able to safely draw the escape wheel round by the last tooth. Thereby entirely stopping the drive to the clock hands. The high tooth ensures a positive gather as the masking pawl rises. Forcing the driving pawl out of contact with the normal height teeth on the escape wheel. (Left click for larger image. Back click to return to the text)

At exactly 30 second intervals (with a very high degree of accuracy) a short, clean, low voltage electrical impulse comes down the wire from the master clock. The release (or relay) electromagnet is energised and snaps its armature to its core. The right angle lever is instantly released from the locking step in the armature. Dropping the masking pawl out of the way. Which allows the driving pawl back into normal contact with the teeth of the escape wheel. The driving pawl starts to gather teeth normally again. The ratchet wheel and the worm begin to rotate driving the wormwheel. The wormwheel shaft rotates the bevel gears and the hands move on again. Without the slight pause ever being noticed by the public on the street far below.

A gear "train" is a series of connected gear wheels. The waiting train mechanism literally keeps the train of wheels (which drive the clock hands) waiting for about a second or two every half minute. Because the ratchet (or escape) wheel rotates once every half minute the worm is rotated twice in one minute. The 120 tooth wormwheel thus rotates once per hour. This speed perfectly matches the required rotation of the minute hand on a clock dial. A simple gear train (called motion work) further reduces this speed by 12:1 to drive the hour hands.

Another view of the Waiting Train mechanism.

An image of the rear of the movement: The worm is on the same shaft as the ratchet-toothed escape wheel. The back of the silver grey ratchet wheel can be seen on the right of the picture. The worm (which looks like a section of threaded rod or a screw is above the wormwheel and in close contact with the wormwheel's teeth. The worm locks its wormwheel against free rotation so it can only rotate as a result of the worm's own slow rotation. (left click for larger image. Backclick to return to the text)

In summary: The heavy pendulum's powerful swing is converted from linear into rotational energy by the driving pallet, ratchet wheel and worm. The worm and its wormwheel greatly increase the torque available to drive the minute hands of the external clock dial(s).

All the parts are very heavily built to cope for decades with the enormous strain placed on the movement by bad weather on the exposed hands of the clock dial. The materials are of the highest quality and the parts precision made. Gents were one of the first British companies to use hard chrome plating. This is used on the worm, the driving pawl, the escape wheel and the masking pawl. To ensure low friction and very long life despite sometimes indifferent lubrication. The plating also protects the steel parts from rust. Many of the movement parts are gunmetal or bronze for very long life in difficult, salty or damp environments. The quality of the lacquering speaks for itself. It is almost flawless after 70 years.

It is remarkable to think that this small movement could drive the hands of 4 dials of 6 feet diameter or two of 8 feet diameter. A weight driven clock movement would have to be far larger to manage this feat. The WT movement could also serve as a powerful and reliable motor for anything which required very slow and steady rotation.

Click on any image for an enlargement. Back click to return to the text.

'WT' Dimensions and electrical requirements.

2008-08-27T20:20:00.008+02:00

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My C40 A Waiting Train movement is approximately 425mm wide across the feet, 387mm high from the underside of the feet to the top of the pendulum suspension, bearing rotation wheel and about 190mm deep. The flat bottom of the pendulum bob extends a further 42 cm below the underside of the feet on which the movement rests. Later models of the C40 A may vary from these dimensions. The main casting took on several different forms as time passed.

The A-sized movement alone weighs approximately 18 kg. The pendulum bob an extra 11 kg. A total of 29 kg or 64 pounds. This is just manageable by a fit adult if a small WT needs to be moved manually. Removal of the bob is essential if the WT is to be moved and placed down again. Do not rest the WT movement on the attached pendulum bob or damage is almost certain! Always remove the bob for safe transport and handling of the WT.

Larger models: B, C, D and E were also manufactured by Gents with a capacity of up to four dials of 28 feet in diameter in the case of the very largest models. These heavy duty movements are often of completely different form to this smallest C40A model. They used much the the same techniques but with greater sophistication.

The pendulum drive electromagnets together have a DC resistance of 46.8 Ohms.
The relay (time) electromagnet has a resistance of 15.2 Ohms.
The spark suppression choke measures 228 Ohms.

There seems to be some variation in resistance between WT movements so there is no need to worry about matching the above figures exactly.

A close-up of the support bracket for the relay electromagnet armature showing the movement number 309 stamped into the brass. This is the usual place to look for a WT movement number.

Note the heavy wax coating to protect the many turns of insulated copper wire of the electromagnet. The wax was partially dissolved by the cleaning fluids I used on the movement: Odourless paraffin lamp oil followed by a warm bath in washing up liquid and water. The coil had to be plunged into clean cold water to quickly halt the melting of the wax. The coils had appeared almost black at the time of purchase but the green dye of the typical Gents' insulating cotton on the underlying copper wire was exposed by the cleaning. Since the movement will not be used in a harsh environment the loss of a little wax is unimportant. The wax could of course be tidied up a little to improve the overall appearance as a display item in a domestic setting.

The terminal block on the left side end of the movement frame.

The top two terminal screws connect the relay electromagnet of the Waiting Train section of the movement. This time circuit connects to a remote and highly accurate, electric master clock which performs the timekeeping duties for the WT movement. The DC voltage supplied will depend on the power required to run all the dials in the half-minute series time circuit operated by the master clock. Though the time circuit is designed to run on 0.22 Amps the voltage will vary greatly depending on the number of electromagnets in series with the master clock.

Each slave clock dial will have its own electromagnet. As will all the other apparatus connected into the time circuit. Including the WT's relay electromagnet coil. As many as 100 dials could be operated by one master clock. Though Gents' did offer relay-operated devices to reduce the number of dials in any particular time circuit. Just to keep voltages to manageable levels. In original installations batteries were often used. Higher time circuit voltages would require a great many more batteries in series.

The bottom two terminal screws connect to the large pair of pendulum drive electromagnets via the contacts operated by the Hipp Toggle and V-block. This movement requires only 20 Volts DC. The 20 Volts DC drive supply will be connected to these two screws. This voltage is easily supplied today by an inexpensive plug-in "mains adaptor".

Warning!

Never connect a WT movement directly to the Mains electricity ! There would be a very high risk of death by electrocution!

250 Volts AC will quickly destroy a WT movement!

There would be a lethal voltage on many exposed metal parts only ever intended for 1A (maximum) 20 Volts DC.

A fire hazard would also exist from violent overheating of the large electromagnets!

20 Volts DC is the recommended voltage for the drive electromagnets of this smallest C40A WT movement. A small, 20-24 Volts DC, plug-in "Mains Adaptor" is ideal. Do not use higher voltages! Do not use AC!

If you must use large batteries fit a suitable fuse in series with the movement to avoid damage in short circuits. Even a small battery has so much power that it can easily cause a fire in a dead short!

Click on any image for an enlargement. Back click to return to the text.

'WT' Videos

2008-08-26T22:13:00.069+02:00

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This chapter was re-published over quite a period of time and clearly documents the amazing progress in domestic AV/computer/camera technology and online video hosting:

An experimental 50 second video taken out of doors with the video option of a Canon Ixus 860 digital still camera. Click on the arrowhead at bottom left of the video screen to set the video in motion. My apologies for the wind noise. Modern cameras usually have a wind-noise cut option.

The Hipp toggle can be seen near the bottom of the frame rattling freely back and forth across the V-block. Early in the video (at 7-8 secs) the toggle drops into the notch in the V-block, contact is made and the rocking armature rises to meet the large electromagnets. The roller on the tip of the armature catches in the hook of the pendulum giving it a good push.

Near the top of the frame the gathering pallet can be seen dragging the escape wheel round one tooth at a time. The hand resetting crank is attached to the same shaft and rotates with the escape wheel. There is a pause as the right angle lever is locked and the gathering pallet slides back and forth out of contact with the escape (or gathering) wheel. A short electrical impulse arrives from the master clock at the small relay electromagnet and the right angled lever is dropped. Allowing the gathering pallet to continue to draw the escape wheel round for another half minute.

Please allow the video to finish before moving on. There seems to be a software glitch when using some browsers if one attempts to move onto another page before the video is finished. The video should appear perfectly smooth in action but is subject to one's internet connection and computer speed and any parallel activities.

I found the You Tube video poor due to the heavy compression at this time. The size of the Google Video screen is much larger: It can even be adjusted to full screen with a click on the box at the bottom of the video screen. Unfortunately, due to the compression applied the Google Video still does not appear remotely as sharp as the original as I see it on my own monitor. Downloading the video is possible and may improve the video experience when played from your own hard drive.

BACK CLICK to return to the text.

Further close-up videos of my WT are available at Google Video. These were taken using a much earlier Sony digital still camera. I would like to replace these videos with some taken by the Canon but there is a remarkable amount of work required to achieve this satisfactorily:

The WT has to be lifted off its stand, carried through the house and taken outside where there is enough light for the video option to work at its best. Sunlight is very undesirable due to excessive contrast and heavy shadows devoid of detail. Yet conditions must be bright enough to give the video some sparkle and life. The WT is very heavy and a very awkward load unless the pendulum is detached. There is only one place in my garden where the background is not distracting and there is plenty of light and this up against a shed wall across the yard. That means at least three heavy loads with intervening steps to negotiate.

A heavy video tripod with pan and tilt head is also necessary for the camera to remain steady. The welded steel stand for the WT must have a very firm base or the WT rocks like mad when running. All unnecessary movement not only looks very silly but detracts from the sharpness of the video for technical reasons. (blurring around the edges of moving objects) The camera *and* the WT movement must both be absolutely level. The WT must be framed without other distracting objects in the background. The 20 Volts DC power supply is necessary for the drive electromagnets on the end of a very long extension lead. A 9 volt battery must be applied at reasonably precise intervals to trigger the relay electromagnet to release the waiting train action. With nothing to resist the WT's driving power everything moves far too freely. The hand setting crank has a nasty habit of flopping down an extra tooth at precisely the wrong moment right in the middle of a"take!"

The intervals between the various activities of the WT movement must be timed carefully by the amateur film maker. If only to limit the video to a reasonable length to avoid massive file sizes or viewer boredom. All this has to be managed simultaneously against the opposition from my long-suffering wife. She does not understand the drive to produce yet more videos of a humble clock.

Last but not least: One must remain absolutely quiet during filming. There must be no wind (at all) or the camera's built in microphone picks it up and reproduces a loud roar! Avoiding heavy breathing, sighs of frustration, crunching the gravel underfoot when starting the camera, triggering the WT's relay and switching the camera on and off without a cable release is an absolute nightmare! Neighbours, dogs, birds and farmers never seem to rest either.

Only when the video is captured can it be checked indoors on the computer screen. Even when a half-decent video has been captured it has to be trimmed carefully with computer software. Then successfully stored and uploaded to the online host. Even adding on-screen text is not easy when occasional dyslexia rears its ugly head. e.g. Canon has only one "n" in the middle? Since when? It's not easy being a one man band at the cutting edge of video blogging. ;-)'

There are now two videos on You Tube of the same WT movement:

And a closer view:

BACK CLICK to return to the text.

The WT shown is later in date than my own having plating on the brass parts instead of clear lacquer. It also has the later cloth-wrapped and resin coated electromagnets. No doubt these details were introduced by Gents to obtain greater cosmetic longevity and improve resistance to damp. There may also have been an attempt to update the appearance as time passed to match customer's expectations. However beautiful, lacquered brass may have been seen as rather old fashioned in the industrial context of most timekeeping installations.

Very few WT's would ever have been seen by the owner or the general public. The WT was simply a reliable mechanism for driving public clock hands. Not the work of horological art which modern collectors admire for its grace and form. Later WT movements were painted pale grey to match the racks and cabinets housing industrial electrical installations and telephony. Which is even further from the delightful greeny-blue paint seen here. Or the much earlier black paint and deep lacquered brass.

Here's my latest attempt to capture my WT with my digital still camera posted on YouTube.
I recommend the "high quality" viewing option for a much crisper picture and one which even stands "full screen" viewing. YouTube used to be much fuzzier than Google Video but has greatly improved its video quality lately:

BACK CLICK from the video to return to the text.

Here my distant Gent's Pulsynetic master clock is connected to reset the Waiting Train mechanism. My past attempts to film the WT involved a 9 Volt battery to reset the WT and required rather more hands than most of us are normally supplied with. For this "hand-held" video I used my heavy video tripod as a "steadycam" stabiliser having become bored with the rather static view from a fixed tripod. The mass of the video tripod certainly stabilised the camera but it was so heavy I was struggling to support it with both hands! I hung an old sheet behind the WT to hide the untidy background mess of my workshop.

A new and better video using the Lumix TZ7 in AVCHD video mode mounted on my iron plumbing fittings "Steadycam". Taken in bright daylight as previous attempts using work lights and florescent tubes produced poor results. Double clicking on the video screen will take you direct to YouTube where the video screen can be seen in the correct format, enlarged or even watched full screen in 720P HD. (optional) Closing the YouTube web page will automatically return you here.

Note that I have now made and fitted replicas of the Hipp Toggle damper and the time setting pointer which were both missing from my movement. If you have computer speakers or are directly connected to an audio system you can hear the sound of the WT in action. The Toggle damper certainly quietens the usual noisy rattle. It also avoids the toggle ever swinging so violently that it lodges in the Hipp V-block (accidentally) on the pendulum return swing. The simple rubber tube fitted to the end of the brass arm damps the sound and movement of the Hipp toggle at very low cost. It provides very long life, perfect reliability and completely avoids mechanical complexity. Typical of all the touches of mechanical genius associated with the remarkable simplicity of the WT.

The time setting dial and pointer were used to check the time showing on the (usually invisible) hands outside the tower or building in which the WT was installed. This facility was also very useful for resetting the hands to British Summer or Winter Time (or its equivalent at the time) in spring and autumn.

It must be remembered that obtaining an accurate time signal was not easy in the past. Nor were accurate watches everyday wear for the working classes who were in charge of most public clocks. With luck the controlling master clock would have a slave dial situated near the WT movement. This would allow the WT itself to be set accurately to time after stoppages, repairs or maintenance. Mechanical clocks may have had time setting dials but could not enjoy the benefits of a an accurate slave dial unless the building also housed a master clock impulse system.

Before the arrival of national, universal time many clocks were set by a local sundial. Hopefully using a set of tables called the Equation of Time. Naturally this often led to considerable inaccuracy where the local timekeeping standard was an medieval piece of clockwork without temperature compensation. Not to mention the variations across the country due to longitude.

The railways finally forced universally accurate timekeeping on most nations. Failure to have accurate timekeeping would mean that a train might have left the station before a vital connecting service from a major city had arrived. Such problems produced commercial pressure to conform to a national time standard.

Click on any image for an enlargement. Back click to return to the post.

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The Pulsynetic C7 Master Clock

2008-08-25T10:38:00.096+02:00

A view of the Gents' C7 master clock pilot (slave) dial with the case door closed.

I have now uploaded an HD video of the Pulsynetic master clock to YouTube. See the bottom of the page.

Only the top of the clock case is shown. The master clock's two electro-mechanical movements are hidden by the dial. The main movement (painted green) keeps the pendulum swinging and the time circuit impulsed at very precise, half minute intervals. The slave movement simply advances the pilot dial in the case and is similar to all the other slave dial movements.

Some Gents' master clocks (C6) were sold without a pilot dial so that the movement could be clearly seen behind the door glass. A pilot dial is very handy if there are no slave dials in the immediate vicinity of the master clock to allow one to monitor the timekeeping. Fixing a slave dial to the wall near the master clock easily overcomes this problem and gives a choice of dial to match one's taste or décor. The advantage of having a pilot and at least one other slave dial is that comparisons will quickly indicate whether a fault lies with the clock itself or a single dial.

A view with the clock case door opened appears below. The brass mechanism on the right is called a slave movement. It is usually hidden behind the steel dial plate and drives the hands on the pilot dial in 30 second steps via a 120 tooth ratchet wheel and a small electromagnet. The small gears visible (horological term for gears = wheels) are the motion work for driving the hour hand from the minute shaft. (horological term for axle = arbor) The pilot dial is placed in series with the master clock's own electrical contacts and all the other slave dials and half-minute impulse mechanisms in the time circuit.

Inside the Gent's C7 Master clock case.

Gent's (pilot) slave dial.

The small gears visible through the large ratchet wheel is the motion work for driving the hour hand from the minute shaft. In a 12:1 ratio. The horological term for axle = arbor. While gears are referred to as wheels. (large) Or pinions. (small)

I have already mentioned that the master clock is entirely responsible for the accurate timekeeping of the WT turret clock movement. The master clock has a 1 second pendulum, driven at half minute intervals by a falling weight. The weight itself is a long, bronze-coloured, metal lever. This is pivoted at one end and has an attached roller at about the mid point. When the gravity arm is released by the catch (at the free end of the gravity arm) the roller runs down the impulse ramp on the pendulum and gives the pendulum a gentle push to keep it swinging. It sounds easy but the invention of a reliable roller and ramp mechanical impulse system only became possible with the aid of electricity to rapidly reset the gravity arm. The advantage of a half minute impulses was the relative freedom of the pendulum in between impulses.

The roller and ramp provide a gentle push with exact repeatability of the same action again and again. Always around the centre of the pendulum's arc where it can do least harm to the timekeeping. The vital factor is that the energy the roller puts into the ramp on the pendulum is almost unchanged from one half minute. And the next and the next for literally millions of gentle runs of the roller down the ramp. If the push is exactly the same then the arc (total swing) of the pendulum will not change and nor should the timekeeping. The mechanical roller impulsing system also found favour in competitor's master clocks.

The exact details of the shape of the ramp and the size of the roller have been modelled mathematically in the search for the best possible timekeeping. In between receiving these gentle impulses, the pendulum is free to swing. Except for the light duty of gathering the escape wheel. Most mechanical clocks are constantly interfering with the pendulum through the escapement. The master clock offers far less interference with the pendulum as a timekeeper. In fact some master clocks can compete for accuracy with regulators. A class of clock where absolute accuracy is their prime purpose.

Thermal compensation of the pendulum is also essential to good timekeeping. The flat pendulum rod of the Gent's master has diagonal lines scribed on the front. This to show at a glance that it is made of low expansion material and not simply a strip of bright, mild steel.

Everything in an electrical impulse clock system relies on the master clock's rate (timekeeping) to remain as stable and reliable as possible. The master clock case would usually be locked to avoid worker's cheating so they might come in late and go home early. Machine running times were often monitored by a recording device controlled by the master clock. Lost time meant lost money in industry. Many factory workers were paid for piece work. Meaning they were paid on their daily or weekly personal production total of the items being manufactured. This system ensured that all worked as hard as possible just to make more than a bare minimum wage. Machine "down time" was a disaster for both the management and the workers. Devices were invented which could monitor the actual run times of the machines in a factory. These relied on the half minute impulses from the master clock to ensure accuracy.

Factory sirens, whistles or bells controlled by master clocks via contact programmers were once commonplace. As were clocking-in machines at factory entrances with wages lost for late arrival. Being a few seconds late could cost a quarter of an hour's wages. Or even more if lateness occurred on several days in any week. Mass production required that all are present on time for the many, inter-related tasks to run smoothly and achieve maximum rates of production. Penalising the late riser in their pockets was one way of ensuring punctual arrival times. It was essential that all clocking-in machines showed and recorded the same time or there was "trouble at the mill". An impulse clock system ensured uniform time throughout the establishment.

Problems sometimes arose when there were regular queues at the clocking in machines. The timekeeping was accurate but the sheer weight of worker numbers in some factories defies description by today's standards in the West. Much work was very labour intensive and repetitive with many thousands of workers in any one factory building. Or spread across a whole complex of buildings. All joined by the thin wire which brought the impulse time system to every corner of production and office work.

Before the age of CAD (computer aided design) drawing offices were often vast areas. Sometimes housed on several floors. All closely packed with desks and drawing boards with aisles in between them. The number of slave dials supplied to a large factory was often beyond everyday imagination. Manufacturers of impulse time systems would list their most prestigious customer's installations in their advertising brochures and leaflets to emphasise their capacity for supplying literally thousands of dials on a single order for a complete timekeeping system.

Meanwhile, back at the vital master clock which controlled it all:

The impulse roller can be seen below (arrowed) resting on the ramp in this posed image of the master clock movement below: Normally the run of the roller down the impulse ramp and resetting is far too brief to be caught on a still camera:

The Gents' Pulsynetic master clock movement. (1961)

Above the impulse roller can be seen the 15 tooth gathering (or escape) wheel. This wheel is pushed round, tooth by tooth, by the gathering pallet as the pendulum swings to the right. At half minute intervals the gathering pin rises into a deeper notch between two of the teeth of the wheel. The gathering pallet extension rises and pushes the gravity arm catch aside so that the gravity arm can fall. The roller runs down the ramp, closes the electrical contacts and the gravity arm is then instantly reset on its catch by the electromagnets. The contacts can be seen at the bottom left of the movement and in the image below:

Close up of Pulsynetic movement contacts.

The closing of the contacts and rapid reset of the gravity arm provides a short, highly accurate, impulse of DC electricity which can be used for a multitude of tasks. All that is required is a low voltage insulated wire to be taken to wherever a very accurately timed impulse is required. Often this is over quite large distances within a factory complex or hospital. Instruments, dials and other mechanisms are all placed in series with the master clock contacts and all of them will keep time as accurately as the master clock itself.

The image above shows the gathering pin resting in the deep notch between two of the teeth of the gathering wheel. The gathering pallet has risen and will strike the sprung catch (on the right) releasing the gravity arm. As the gravity arm falls the electrical contacts will meet and the gravity arm will be reset on the catch by the two large electromagnets. The action of closing the contacts sends a brief electrical impulse through the entire clock system. Advancing all the dials by one half minute and resetting the 'WT's waiting train mechanism.

The image above shows the effect of pulling on the cord which hangs inside the case on the right of the movement. A sprung lever is drawn down behind the movement which has a long pin pointing forwards. This pin directly pushes the gathering pallet continuously downwards. So, instead of the end of the pallet passing freely through the hole in the gravity arm catch it strikes the catch below the hole on every swing and releases the gravity arm. The gravity arm drops, electrical contact is made and all the mechanisms and dials in the master clock's system are now advanced every two seconds. Provided the cord is held down the system will continue to be impulsed on every pendulum swing to the right.

This is useful for advancing the clock dials for summer time. Or for resetting the system after maintenance. It should be noted that using the cord to achieve rapid advance requires some form of damping of the pendulum. Otherwise the bob will quickly build up such an arc that it will hit the case sides. I use a bath sponge to stop the bob knocking the case wall. The sponge is removed from the case after the dials have almost reach the desired time. The final adjustments to time are made by releasing the catch manually or pulling the cord briefly to "creep up" on the reference watch or clock.

Setting the master clock to the exact second is achieved by rotating the escape/gathering wheel a tooth or two by hand as necessary. One has to be very careful not to trigger an unwanted release of the gravity arm. Sometimes it helps just to lift the back click so the escape wheel is not gathered for a second or two.

It is best to stop the pendulum if the clock dials are to be set backwards by more than a few seconds. Even with an impulse 15 times as often it still takes a very long time to go "right round the dial" to make up 11 hours. Any contact programmers (for bells or factory sirens or whistles) in the time circuit will also lose their day setting if one advances the master by a full 11 hours simply to achieve an hour's retardation in the time circuit. There is also a very good chance of the impulse dials in the circuit becoming scattered in the time they show. A WT turret clock movement in the circuit will also become thoroughly confused and have to be reset. So stopping the pendulum is the best course best for retarding the time circuit.

Once a clock has been adjusted to very accurate timekeeping very small changes in rate can be made by placing small weights on the pendulum bob. A small weight placed on top of the the bob will speed up the clock by a few seconds per day depending on the weight itself. Conversely, a weight placed below the bob on the large rating nut will slow the clock slightly . Normally the clock would be adjusted to run just a few seconds slow per day. Then small weights would be added to the top of the pendulum without stopping the clock. Stopping or even touching the pendulum will almost always affect the previous rate so is best avoided. The top of the pendulum is easier to reach than the rating nut and is travelling more slowly if weights are to be added or removed.

Bronze finished, steel cased, Pulsynetic pendulum bob.

Strictly speaking a clock can be very accurate indeed but still have a slowing or gaining rate compared with standard clock time. It is the absolute steadiness of the rate which is so essential. Once the rate has been measured precisely against an accurate time signal it (the rate) can then be adjusted to match "normal" timekeeping. (i.e. neither gaining nor losing) Usually this is done by adding small weights to the bob using tweezers to avoid touching the pendulum bob itself. Master clocks were often provided with a small wooden box containing suitable weights to fine adjust the timekeeping. Sometimes a weight tray was provided half way up the pendulum rod. Though this was not normally done with the Pulsynetic master clock. The pendulum bob top has a raised rim to stop weights from falling off too easily.

Master clocks must be bolted to a really solid wall to give their best timekeeping. If the wall should move or be subject to any vibration this will often affect the timekeeping. A solid brick or block wall is essential. Hanging a master clock from a partition wall will often stop the clock if it will run at all. The clock relies on the solid fixture for its pendulum suspension to allow it to swing steadily. Rarely will a master clock run if stood up on the floor. The movement of the Pulsynetic is provided with fixing holes so that the movement itself can be bolted very firmly to the wall rather than relying on only the case being well fixed. Screw holes near the bottom of the case are also provided to ensure the case itself is fixed firmly and exactly upright in all planes.

Uprightness for-and-aft and from side to side is essential to the accurate and reliable running of the clock. Large metal or hardwood packing spacers placed over the fixing bolts are best if the wall is not absolutely plumb. The clock must not be allowed to move relative to the wall once it is fixed. Don't take it for granted that all walls are upright. There are few bricklayer's levels which have not had a tumble from the second or third floor. I once had some new internal block walls built by a bricklayer who managed to build them 2" out of vertical thanks to his battered and mortar-encrusted level. I had became irritated by my newly hung-hall doors constantly swinging open or closed. He was quite cross when I bought a brand new four foot level to show him the quality of his workmanship. He hurled the level from the scaffolding complaining sarcastically about amateur builders not having a clue. By then it was much too late to demolish and start all over again. So take nothing for granted where the verticality of walls are concerned!

A decent, tubular aluminium level costs very little indeed these days and is a good investment if you want the best from your master clock. Check the level's accuracy before leaving the shop by checking the floor and a wall carefully. Then simpæy reverse the whole level end for end. Or back to front on a vertical wall. Though you can turn it end for end to double check.

The bubbles should rest in exactly the same place in their glass tubes relative to the line markings despite the whole level being reversed. Don't waste your money on laser levels without checking them carefully before leaving the shop. This is rarely possible as the kit usually comes sealed in a carrying case. Levels with rotatable dials to measure slope angles are rarely accurate enough so don't go for one of those either.

A plain, rectangular, tubular four foot, aluminium level is ideal for all sort of jobs around the house and garden and will span the full height of a master clock case nicely. Gent recommended a plumb line be used to ensure the clock case was dead upright but I still prefer the long level held against both sides of the clock in turn.

Even hanging more than one clock on the same wall will often affect their timekeeping. I once had several master clocks fixed to the same workshop wall and found that two of them would stop regularly. This was simply because the wall was being moved imperceptibly by the clocks themselves as their pendulums swung in or out of unison (or phase) with each other. Being out-of-phase effectively moves the wall cyclically away from the pendulum fixing point. Resulting in a loss of power to the pendulum sufficient to bring it to a complete stop despite the regular mechanical impulsing.

When master clocks are being displayed at exhibitions and museums it is often difficult to find a suitable wall which suits the desired layout. Fixing to partition walls will often cause the clock to stop. Nobody wants to drill a solid exterior wall just to hang a master clock for a relatively brief display or exhibition. Sometimes a very large sheet of 3/4" (18mm) plywood is used to stiffen up a lightweight partition wall just for the period of the display. The clock is bolted firmly to the plywood which in turn rests on the floor for extra support and is very well screwed to the partition wall studs. Not ideal but will give a safe fixing for the length of the public display.

If you own a master clock it really deserves to be bolted to the bedrock down in some deep, dark cellar if absolute accuracy is desired. Failing this, bolting it to a thick brick or concrete wall is the next best thing. Lightweight building blocks are inferior for clock mounting as far as maximum resistance and mass are concerned. If the pendulum puts any forces into the wall then the wall must push back with equal force. (Newton's Law)

Achieving perfection has occasioned the building of massive concrete blocks into the solid rock in very deep cellars and dungeons where the finest possible timekeeping in the world was required. The cellar also had the advantage of offering a very stable temperature all year round. No doubt you will find a suitably solid location where the clock can be enjoyed and still keeps good time unless you live in a lightweight timber building.

I can still remember when the Pulsynetic master clock was being removed and sold at the main line, local railway station. (back in the 1970s) A delightful little weight driven turret clock was also sold off at the same time. My optimistically low bids were greatly exceeded as both clocks fetched a very good price indeed. The problem was trying to compete with those who love railways as well as clocks. When a clock has documented history it also gains in value well beyond the norm. It took me another 20 years to find another Pulsynetic master clock for sale. These days you can compete for them on eBay! Provided you are willing to bid against the rest of the world.

By the way: The Pulsynetic master clock is not everybody's idea of domestic bliss. They produce quite a loud clonk every half minute. If you have bolted it to a solid wall the sound will probably travel right through the structure of the building! Tolerance of a noisy clock is highly variable! I found I soon ignored my master clocks when they shared a workshop wall. They are rather like grandfather (longcase) clocks. Despite the whirring and the loud bells I quite often didn't notice half a dozen of them striking, when they were on test and I was busy repairing another clock.

Judge the sound for yourself:

Click on any image for an enlargement. Back click to return to the text.

Pulsynetic system programmer.

2008-08-24T18:55:00.029+02:00

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One very useful accessory for Pulsynetic impulse clock systems was the adjustable programmer. This could be used to ring electric bells and and sound factory sirens. It was commonly used in schools to mark the beginning and end of classes thanks to its reliability and accuracy. By removing the human element, classes, or other regular events, could be timed almost to the second almost indefinitely. Moreover the bells would ring simultaneously throughout the entire school without human intervention.

The Gents' Pulsynetic programmable contact maker.

The programmer relies on a beefed-up version of the Gent's slave dial mechanism. Through a simple system of gears the programmer's large ring is advanced at half minute intervals by the slave mechanism. On the impulse dial mechanism itself is the minute dial. Large slaves like this were sometimes used for larger public clock dials. Though usually the hands would be behind glass to avoid "weather resistance" to the limited torque available.

The very large ring at the rear has holes at 5 minute intervals where tapered pins can be inserted to actuate the electrical contacts. (on the extreme left in the top image) The disk on the left is the day of the week dial which allows the contacts to close. Or via a simple cam on its edge blocks them from closing. By this means the bells can be silenced during the weekend when the school is normally closed. A push button (at bottom left) allows the bells to be rung continuously as an alarm. Perhaps in the case of a fire drill or other emergency. The programmer was usually installed near the master clock in the headmaster's office or that of his (or her) secretary.

The rocking mercury switch provided a fixed and limited period of bell ringing of 7-8 seconds. Without it the bells would ring continuously, once closed, until the pin finally cleared the contacts.

The Pulsynetic bell ringer. Or programmable contact maker.

Left click for much larger image. [300kB]

Full description: The contact maker can be thought of as a clock, or time switch, with three dials which rotate against fixed pointers. These indicate the day of the week as well as showing the (24 hour) time and the minutes of the hour:

The electromagnet is activated by the master clock's brief impulses at 30 second intervals. This part of the mechanism is a modified, heavy duty, double locking, slave dial movement. The minute wheel and star wheel are rotated by the ratchet (or impulse) wheel as one unit. All three turn once per hour driven by the electromagnet. The purpose of the 12 point star wheel is to continuously lift and reset the mercury switch and then release it again at 5 minute intervals.

The mercury switch fixes the duration of bell ringing to about 8 seconds. This is achieved by the mercury running slowly back, through narrow channels, away from its internal contacts.

The day of the week wheel is really a simple cam driven by a pinion on the 24 hour wheel. The day of the week wheel has a normally-closed, bronze, contact finger rubbing along its lower edge. At the weekends an optional cutaway on the edge of this wheel allows these sprung contacts to open. Thus breaking the bell circuit. Which stops the bells ringing all weekend until the raised edge finally returns on Monday. Closing the contacts again.

Weekend silencing is a mechanical option. Gent's used to say that changing the programmer had to be attended to by their own engineers. Ringing is dependent on the weekend contacts being closed. This can cause some confusion in new owners/clock carers who cannot understand why the bells don't ring when a pin is set. A glance at the bottom of the day of the week dial should confirm whether weekend silencing is active.

Careful examination of the day of the week wheel in the image above shows that I have turned the removable back plate. The day of the week contacts remain continuously closed. Allowing ringing at weekends as well. The thin grey line of the back plate can be seen in the normally cutaway weekend sector. Removing the retaining pin and bush from the day of the week wheel will allow access to the backplate. Be very careful if you are tempted to try this. There is a large and heavy, bronze, toothed wheel (gearwheel) behind the day of the week wheel. As you slide the wheel free be ready for the unexpected weight. You will also need to reset the day of the week accurately when you replace it! (see setting instructions below)

The 24 hour pin wheel has holes around the periphery at 5 minute intervals. It is driven by a pinion from the minute wheel of the slave movement. When a stout, tapered, timing pin is placed in any of these holes it will eventually arrive at the bell contacts at the extreme left of the mechanism. The pin closes the contacts, completing the bell circuit at the time shown on the pin wheel dial.Being a 24 hour dial the pins must be placed where they will cause the contacts to close only at a desired time. So pins are usually only required during the working hours of the school. So no pins are fitted during the evening or hours of the night. This simple arrangement allow night silencing without the extra complexity of driven wheels, cams and contacts.

Any single contact in the programmer's circuit cannot ring the bells. All must be closed at the same time. The bell contacts are closed by the timing pin for several minutes. The mercury switch is then released by the star wheel. Only if the weekend contacts are closed will an applied low voltage DC current pass through the entire bell circuit. Note that the bell circuit has no connection to the clock impulse circuit. Separate, labelled connection terminals are provided for both circuits (time and bells) at the front, inside the secure case.

If a heavy current, or a higher voltage is required to be switched, then a suitable relay may be switched by the low voltage bell circuit. One should not try to switch mains electricity or higher voltages DC with the programmer's bell circuit. Higher voltages will cause arcing and should be strictly avoided. These higher voltages would make exposed metal, screws and wires live! Which could easily prove lethal if touched accidentally! A fire is also entirely possible due to overheating of components.

Programmer time and day setting: Thanks to the clear markings on the various wheels the time and day of the week can be read off the programmer. Naturally these wheels must all be set accurately when the bell ringer is put into use. The day of the week wheel may be set quickly by removing the tapered pin and bush which retain it on its arbor. Do not lose these parts. The day of the week wheel may then be drawn gently forwards and out of engagement with its drive pinion. Then turned to the desired day before being very gently pushed backwards again to engage the large, toothed wheel with its driving pinion. The exact placement (rotation) will depend on the time already showing on the other two wheels.

It is easiest to set the day of the week dial at a particular time since it lacks any other sub-divisions than midnight between any two days. Midnight may be easiest to set accurately but is hardly a user-friendly time to be setting the mechanism. Using other times will require some guesswork. The time of day on the day of the week wheel is read from the point where the weekend contact finger rests underneath the wheel. So setting the day of the week wheel is best carried out at 6 or 12 o'clock. Being a quarter or halfway through the day shown against the bottom pointer. Midnight would of course be on the line between two days. Once set it will continue to rotate with the mechanism and show the correct days of the week. So setting only needs to be done once and can be checked for absolute accuracy if you should happen to be around at midnight. Check that the other dials agree that it really is midnight. Remember to replace the retaining drilled bush and tapered pin before you lose them.

The minute wheel may be advanced by repeatedly pressing the armature against the electromagnet core and releasing it briefly. The slave movement which drives the entire mechanism has double locking. This makes it very difficult to advance quickly. (Unlike a normal slave which needs only the electromagnet armature to be pressed in to release the ratchet wheel)

There are certain midpoint positions of the locking and impulse levers which will allow the ratchet wheel to turn freely. But it requires some care and dexterity to avoid graunching the ratchet wheel with the levers if they should suddenly re-engage! Probably no damage will be done but it isn't a kind way to treat such a fine, old mechanism.

Freeing the minute wheel will also allow the 24 hour pin wheel to turn as they are geared together. The time on the 24 hour pin wheel is read at the bell contacts whether a pin is present or not. A pin may be inserted temporarily to ensure accuracy of reading the time showing on the 24 hour dial. There should be no disagreement between the time shown on the minute wheel and pin wheel unless the mechanism has been previously dismantled.

A black pointer is provided to show the time on the minute wheel of the slave movement. (Accurate only at the half minute time impulse)

Although the contact device is commonly known as a bell ringer it may be employed to switch low voltage currents for any purpose. You could even use it as an alarm clock with a suitable low voltage doorbell or buzzer. Or to switch lights on and off via a locking relay.

Mercury

Great care should be taken with the glass, mercury switch. It contains liquid mercury within a thin glass envelope. It is held by strong spring clips but can slip free if touched. Mercury vapour is highly toxic. Liquid mercury must never be allowed to remain if spilled indoors. The mercury switch is very shiny and the flowing metal very unusual in appearance. This may make the switch attractive to curious children. It is strongly suggested that the programmer case door be kept locked at all times and the key kept somewhere secure and completely inaccessible.

Mercury Spill Response -- Cleaning Up Small Spills

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Gents' slave dials

2008-08-23T12:21:00.046+02:00

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Gents' slave dials could be found in many establishments from schools, to office blocks, palaces, factories, stations, airports and hospitals. The Gents' master clock and slave dial system could be installed anywhere to provide uniform time across a whole complex of separate rooms or buildings. All would be wired in series with the master clock. Here is just a very small selection of the many styles of slave dials available. Some slave movements were even housed in mantle clocks.

An 8" dial with 12 and 24 hour markings and convex glass. The advantage of convex glass is that it diminishes the size of reflected images from windows, lights and skylights. Flat glass reflects the full size of the bright object. Often concealing the clock hands completely. The slave movement from the dial above is show below.

Standard Gents' slave dial movement. Note the cork insulation pads to reduce noise transmission to the case. Notice also the keyhole cut-out in the hidden hanging bracket. This is common to most Gents' slave dials of normal size. This allowed the dial to be simply lifted free from the wall without tools by lifting slightly. The dial may then be examined, oiled or adjusted and returned effortlessly to its place on the wall. Painters and decorators, made aware of this simple facility, could have saved themselves the difficulty of painting carefully around the dial. Yet many/most slave dials still have repeated paint marks around the perimeters of their cases.

Re-hanging such a dial is a matter of tipping the bottom outwards to peer between the wall and the back of the dial. You should ensure the larger area of the keyhole is placed centrally over the wall fixing screw. Then lower the dial flat against the wall and allow to sink down the wall surface by half an inch. (12mm) Now try to slide the dial gently, from side to side. This should instantly confirm that the dial hanging bracket is safely held by the hanging screw in the wall. Pulling gently downward on the dial will further confirm that the screw is safely held by the smaller diameter at the top of the keyhole cut-out. Only then may one safely let go of the dial.

Similar slave dials must have been made in their hundreds of thousands. Providing accurate, uniform timekeeping to government, industry, commerce, education and the health services around the world. The size of the dial would be determined by the distance from which it would normally be read. Or larger still, if it was really intended to be noticed. Like an advertising clock outside a jewellers shop. Or other business, which would hopefully be seen from the other end of the high street.. Sometimes the dial would be oversized if it was important that it should be noticed. Such as at a train or bus station, for example.

The service of providing the time, free of charge, was once much used in advertising and business promotion. Particularly before it became commonplace for the general public to own accurate watches. A time service required accuracy and reliability or the poor timekeeping would reflect badly on the business. The cost of installing a master clock and advertising dial on the façade must have been less expensive, and much less trouble, than a weight-driven turret clock movement. I knew of several shops in one town, in the UK, which all had their own master clock and prominent advertising dials. Perhaps they had a very persuasive, local salesman? Or they each copied each other?

Many different styles of advertising dials were made to hang outside business premises. Sometimes double sided or even three or four sided. Plain or highly ornamented to taste. Usually with slightly larger, double locking slave dial movements. Or designed to be driven by mechanical lead-off rods from a WT. Depending entirely on the size of the dials involved and whether exposed clock hands were desired.

For corrosive or potentially explosive atmospheres Gents' could provide sealed, very heavy, cast iron dials. These avoided all danger danger of naked electric sparks and resistance to attack or damage. These iron dials are quite popular, when suitable restored, as external dials on the homes of clock collecting enthusiasts.

Here is a 25" diameter example of a cast iron slave dial on an eBay auction. This one is slightly larger than the more normal, 18" dial of this type. This dial fetched just over £250 (Dec 2010) in case you were wondering. It is so heavy than only an adult may just be able to lift it. Normally they would be glazed. On a sheltered wall, or under an overhang, protected from the worst of the weather, they would look much better without the glass. Much more like a traditional turret clock dial.

I once had a smaller example of one of these iron dials but traded it in towards another master clock. The dial was really, quite remarkably heavy. Had it been a slave movement, rather than having a mains motor fitted, I would probably have kept it. Ah, the wisdom of hindsight.

I had a large double-sided station dial, as well, but it was far too large to be of much use to me. Again it was traded towards another master clock. The two slave movements inside looked about the same size as standard wall dials but had double locking. Which made hand setting extremely tedious.

Slave dial hand setting:

Normally one can just press the armature against the electromagnet core and whiz the hands round the dial by pushing on the large ratchet wheel. One quickly reaches almost to the time to which it is desired to set the hands. Then one releases the armature to relock the movement. Pressing repeatedly on the armature, against its return spring, will now bring the hands to exact time in half minute jumps.

Usually the master clock is still running and one should allow it to impulse before finally setting the hands to the exact time. Otherwise the dial will show a half minute fast and you will need to go right around the dial again. Hopefully remembering to stop slightly short of the real time. Though I usually insert a fingernail between the armature and electromagnet. Just to stop the movement impulsing for the next half minute.

Double locked slave dials may have a special lever to aid rapid advancing. Though usually one must resort to manual dexterity by holding the impulsing and locking detents clear of the ratchet wheel. The wheel can then be spun to show the correct time with one's third (or fourth) thumb.

An 18" slave dial with pressed steel case and flat glass. Large enough for an assembly hall, canteen, station, corridor or school gymnasium. The poor weather protection makes it obviously intended for indoor use. Plain baton hands are used here suggesting a later dial. Note the superb clarity of a dial meant to be read from a distance. The distortion in shape is due to the low camera viewpoint. Being indoors the glass reflects no distracting light.

I have taken advantage of another eBay auction to share some excellent images of a Gents "W1" turret clock, slave movement. Don't ask me about copyright. I have no idea where eBay auctions are concerned. It is not my intention to profit from sharing these images or information. One must hope that the seller sees such image borrowing as beneficial during the period of the auction. And won't care after the event.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=290511932216&category=96765&_trksid=p5197.c0.m619

The usual, back view showing the drive electromagnet, double locking and over-dimensioned components. All designed to handle the heavier loads of larger clock hands over a long period of service. Notice how compact the slave is and how easy it would be to fit into a small recess in a wall. Or behind any partition. See my "bell programmer" chapter for the use of a similar, oversize slave movement to provide motive power for a programmable, time switch.

Side view showing the hour pipe and minute arbor and motion work between the plates. Interestingly, Gents has gone the extra mile and provided a bronze minute shaft and brass hour pipe. Thus hoping to avoid potential corrosion problems. The movement was supposed to be used with the hands behind glass. However, breakage in an inaccessible situation might mean he clock being required to perform for a extended period in a less than weather-proof situation. Even though this was not the manufacturer's original intention it was guarded against from long experience.

The length of the hour pipe and minute shaft suggest it was designed to protrude through a wooden building rather than through a brick wall. The seller suggests a 3' dial capacity behind glass. Under the protection of a deep roof overhang or indoors it could manage with exposed hands provided (as always) that they are well counterbalanced. (to void the movement having to lift the heavy minute hands before the hour) Exposed hands subjected to the weather should probably be limited to less than half that dial diameter. Note the complete lack of any ferrous materials which might rust and shorten the life of the movement.

The side which would rest against the back of the dial or perhaps a partition wall. The seller suggests 24V DC minimum to achieve a brisk hand movement from the short, half minute impulse of the series clock circuit. As always, the freedom from regular rewinding made such movements attractive for inaccessible positions such as gable ends, chimneys, stables or barns. The limitation being that a glass dial cover was highly desirable to protect the hands from bad weather. The limited torque available might not cope well with ice, snow or gales. Here the WT would offer power aplenty but at much greater expense, bulk and complexity.

One serious problem with glazed dials with plane (flat) glass is the difficulty of reading the time through the highly reflective glass. Particularly out of doors where a cloudy sky can completely obscure the time by reflecting in the glass. I do not think glazed dials are particularly suitable for church towers or other raised situations. Where the sky is very likely to spoil the view of the clock hands during many, unfavourable sky conditions. I pass a rural house regularly which has a glazed dial raised high on the façade. It is extremely difficult (and usually impossible) to read the time under any lighting conditions. An overhang above a glazed dial will often help to reveal the hands more clearly by reflecting a dark surface instead of the bright sky.

A sheet copper cased 10" slave dial from 1937. One of a matching, signed pair with the same dates and consecutive numbering. The copper should really be polished and lacquered but I have never quite got around to it. The hands are typically Gents'.

A standard Gents' slave movement from 1937 with green, silk covered, copper wire.

The two large, brass screws at the bottom are for the low voltage, series, time impulse connection from the master clock. Soft, felt pads help to reduce the mechanical noise from the dial makes when stepped forwards by the electromagnet at each half minute.

An 8" dial with a convex Bakelite case and convex glass typical of office and classroom. I can still remember the long delay between the half minute clicks of the slave clock during the more boring lessons at school. Since I was usually so well behaved it was a once-only treat to watch the master clock and programmer in the headmaster's office while waiting for his return.

Dials were also made with seconds hands but these needed extra components in the master clock. No doubt the noise from these dials dial could be a problem in some circumstances. Gents provided silent movements as part of its range where any noise was a problem. Such as in radio, TV and music studios.

Gents' also made mains, synchronous motor, driven dials. Often of exactly the same outward appearance as the impulse slave dials. These mains dials were only as reliable as the mains frequency itself. So these dials could not guarantee the uniform and accurate timekeeping of the master clock controlled, impulse system. A power cut (outage) for any reason, would stop the mains driven dials. These were usually made non self-starting to avoid a working dial showing completely the wrong time. Over a large building the effort and expense involved in caring for mains dials could be prodigious. Just as it would be today with (supposedly) cheaper, independent, quartz dials.

An impulse clock system would usually have trickle charged, backup batteries and happily continue running for the duration of the power cut. Synchronous mains dials can usually be recognised by a motor starting and hand setting rod or knob protruding from the bottom of the dial case. Though not always. So if you do find a dial for sale ensure it matches your needs by checking around the back. It should be obvious whether a standard, rectangular, Gents' Bakelite cover conceals a slave movement. Or a tin can is hiding a synchronous electric motor.

Those seeking more examples form the entire Gent's, impulse clock system, by an acknowledged expert on their history and components, should visit the following, beautifully illustrated, website:

Home: http://pulsynetic.eu/

Different Gents' dial movements:
http://pulsynetic.eu/?page_id=9

Click on any image for a larger view. Back click to return to the text.

Back click to return from a linked website.

Gents' Instructions booklet

2008-08-19T17:50:00.010+02:00

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Every Gents' Pulsynetic master clock was provided with an instructions booklet. It should be safely housed in the fittings provided within the clock case to avoid loss or defacement. Failure to do this will result in the booklet being lost or used for scrap paper. The next member of staff, responsible for the clock, will have lost the vital instructions for simple maintenance.

As a service to those who have lost their instructions booklet I have scanned and reproduced the contents here. Clicking on the page images will enlarge them. Clicking on the enlargement will make them even larger. You may like to download and save the enlarged images for printing. They should be of sufficient size and resolution to be easily read. For those still on a slow connection each page enlargement is just over 300kB.

I have reserved the instructions pages for the WT for the next chapter. These were in the same booklet but it would make this chapter rather long to have included them here.

Front Cover

Inside front cover

P10

P11

P12

P13

Circuit Diagram 1

Circuit Diagram 2

Click on any image for an enlargement. Back click to return to the text.

Gents instructions booklet Turret clock section

2008-08-18T16:06:00.008+02:00

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With every Gents' Pulsynetic C6 and C7 master clock a set of instructions is provided as a booklet to be placed safely within the case. Wooden fittings are provided inside the case to ensure the booklet remains safely with the clock. It is strongly advised that the instructions booklet be left inside the master clock case to avoid their separation. This will help to ensure that new staff, or new owners taking over the clock installation, will always have the instructions readily available. While these clocks are reliable and not difficult to maintain the instructions will allow a competent person to carry out lubrication and minor adjustments without resorting to guesswork. Leaving the instructions lying around is a perfect invitation for them to go missing. Or to lose pages, be used as scrap paper for phone numbers or become begrimed by curious thumbing.

Normally a master clock would be installed by skilled and trained personnel. Once they have left and any maintenance contract expires then the owner of the clock must rely on the instructions provided. There is always staff turnover and losses due to sickness, accidents, promotion or retirement. One can never rely on a trained or interested person being there for perpetuity. So do leave the booklet in the case.

For those who find themselves with a Pulsynetic master clock and no instructions booklet I have scanned and reproduced the Turret clock section below: These pages relate only to the Gent's Turret clocks. ie. Large slaves or the Waiting Train turret clock movement: If you left click on the page images they should be large enough to read easily. Clicking on the enlarged images again should enlarge them further in some browsers. Feel free to copy these enlarged images if you want to print your own set. I can't imagine how anybody could easily profit commercially from downloading and saving them. These instructions booklets probably still exist in their many hundreds.

P13

P14

P15

P16

P17

Diagram 3

Inside back cover

Rear cover

Click on any image for an enlargement. Back click to return to the text.

Different 'WT' movements:

2008-08-16T13:45:00.007+02:00

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A Dutch collector has kindly allowed me to share some images of his own WT movements. These are both shown in the early stages of restoration but make excellent examples as evolutionary steps between WT movements over time.

Click on the images for larger versions. Back click to return to the text.

This WT movement, No 662, is the same size but a little later than my own. The paint is now overall grey with plated brass parts. The cast iron main frame has developed a sloping section above the power electromagnets. No doubt this offered some improvement in the strength and stiffness of the frame thanks to better triangulation over the earlier curved frame design.

The masking pawl has taken on a curved form on the underside perhaps offering a slower lifting action with less wear on the D-shaped pin. The Hipp toggle damper base has been moved to the very edge of the cast frame. My (missing) damper would have been fixed to a plate screwed to the cast bar just below the bevel gear cluster. The electromagnets are now bandaged and probably varnished or resin coated for insulation and waterproofing.

Only two bevel gears suggest a clock dial (or dials) placed well above the movement and driven by a single lead-off rod via the forked "universal" coupling. Probably with further bevel gears to achieve a horizontal drive to the hands of the clock dial or dials. This would allow the movement to remain easily accessible in a lower room instead of being raised to the clock chamber behind the dials themselves. The other forked universal joint would allow another dial or mechanical drive on the same level. The hand setting dial is on the upward facing bevel gear with a pointer fixed to the main frame nearby.

A metal Gents' label is affixed to the mainframe cross bar below the bevel gears. I have seen this label in this position on other movements of this period and later.

No doubt this movement has been photographed immediately after purchase and will clean up nicely to look very smart indeed. Even a simple wash with a damp cloth and washing up liquid can work wonders on a movement which has simply collected a little dust on its shoulders. After completely dismantling my own 'WT' I used odour free lamp oil to remove the inevitable oily residues. Followed by a soak of of each part in a bowl of ordinary washing up liquid and warm water. The parts were then carefully dried on an old towel, then polished with paper towels. The finish on the painted frame and the brass parts needed no further restoration.

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C40B:

Here is something completely different from the previous model. A C40B. This is the next larger model after the C40A illustrated above. It has a much more solid, modern and functional appearance than the smaller movements illustrated earlier. A no-nonsense, dependable, timekeeping workhorse. One which is still a very attractive and highly desirable, horological collector's item.

Note the much larger wormwheel and bevel gears to match the heavier loads on the hands of even larger clock dials. The much heavier, web-reinforced, cast frame design has a cut-away form to expose the bevel gears and wormwheel. The worm/escape wheel shaft itself is supported on a sturdy plate at the front with a bridging bar at the rear.

The hand setting dial is facing forwards with a long metal pointer on the left at 9 o'clock. There is the usual, small crank and handle on the worm/escape wheel shaft to allow rapid resetting of the hands in the event of a maintenance or power cut stoppage. Or to make the hourly Winter/Summer Time changes. There is very little resistance to turning these handles thanks to the reduction gearing of the worm and wormwheel. The time to the exact half minute is easily set using the small dial on the forward-facing bevel wheel. The electrical contact steady bars are now pressed from strip metal with softer bends rather than being cast brass with the sharper bends of earlier models.

The overall concept remain the same but everything is scaled up and strengthened to cope with the greater loads placed on this larger movement. Here there are four forked couplings for four large dials probably on the same level as the movement high up on a tower. Lead-off rods, with a matching crossbar to fit the slotted coupling, would allow for any slight misalignment. There is also enough linear freedom in the slots to allow for building structural movement and thermal expansion and contraction between the WT movement and the motion work behind the dials.

Note the metal pegs jutting up from the frame casting foot. These are designed to make levelling of the movement easier in the absence of flat surfaces to the main casting. These pegs are fixed to the foot and the very top of the cast movement frame to ensure perfect levelling in both planes. The green cylindrical object just below the wormwheel is actually a wire-wound, spark quenching, resistance coil to protect the main contacts.

The worm shaft has a sprung thrust bearing probably intended to give a little freedom in the event of a total lock up of one of the lead off rods, dial motion work or even the hands freezing solid on the clock dials. The worm will move forwards above its wormwheel instead of rotating it. This may have been a form of mechanical insurance. Since the WT generates such enormous torque it might otherwise damage something in the drive train in the event of a catastrophic lock up beyond the wormwheel in the drive train.

I am most grateful to the owner of these WT movements for sharing these images with me and hopefully a wider audience.

If anybody else has any images of any WT movement I would be grateful for copies by email. Your anonymity is (of course) guaranteed unless you wish otherwise.

_______________________________________________

A very large WT:

Here are two images of a very heavy duty 'WT' movement which I have scanned from an old book. Note the huge wormwheel and bevel gears. Obviously intended to handle the loads involved with huge and heavy hands on very large, exposed, public dials. The pendulum bob looks suitably massive while the contacts look very complicated indeed. This WT uses a crutch to connect the pendulum to the movement whereas all the smaller movements act directly on the pendulum rod. It may be that the crutch is only to connect the pendulum to the electrical contacts.

Unfortunately the original illustrations are not sharp enough to be certain of the exact details of this very complex movement. Not even when enlarged. It is likely that the contacts were self-latching to ensure firm contact without bounce or chatter. They would carry considerable current at higher voltages. Dealing with the problems of sparking and back emf, from the electromagnet coils, would require special arrangements completely unnecessary with the much smaller WTs.

The table or bench on which the movement sits does not look as robust as those seen with smaller WT movements. Suggesting (perhaps) that this is a Gent's assembly or factory workbench. Rather than one intended as the final support for such a serious movement. The reaction forces from the pendulum alone would be likely to make a bench like this sway rather dramatically. Perhaps this particular support bench is of welded steel or even cast iron? Making it considerably stronger and stiffer than the usual wooden benches associated with smaller WTs. Such large movements tended to be installed on masonry or low concrete pillars to provide a suitably rigid and massive support. Any movement in the supporting structure would rob the pendulum of power requiring many more driving impulses than otherwise necessary. Any swaying might even endanger the building structure!

The standard WT movements were listed as running from C40A (the smallest) to C40E. (the largest) Capable of driving the hands on four dials of 5' diameter right up to a truly colossal four x 28' diameter! In some cases multiples of single, large movements were employed for the largest clock installations.

Here is another scanned image from 1911 of a very large dial from a Gent's Waiting Train installation in Liverpool being used as a formal dining table. There are 39 people seated and one standing. With plenty of elbow room for each. Probably intended as a publicity photograph but it speaks volumes about the pride surrounding such a large clock installation. A WT was cutting edge technology of the time. It met a strong desire by big business for conspicuous new architecture. Not to mention the largest possible clock dials to emphasise their importance to world trade. Public timekeeping was also a service. Electricity was a relatively new and exciting form of energy. The combination produced orders for WTs from right around the world.

There is a fascinating and detailed account of the design and construction of the record breaking WT clock installation in Liverpool. Written by Colin Reynolds FBHI. A former managing director of Gents of Leicester and leading expert on the history of the company and its products:

The Great George Liver Clock : Reprint

A weight driven clock to move the hands of four dials on this scale would have needed to be far larger than that at the Palace of Westminster. (usually going under the name of 'Big Ben' but which actually refers to the large bell used for striking the hours. The Westminster Clock is its official title. The regular rewinding of the huge weights involved would have required a whole team of strong men. The WT needed no winding and could be scaled up to almost any size.

______________________________________

A very rare appearance of a WT movement on eBay has produced some remarkable bids with some hours still left to run as of this entry: A difficult object to value with so few appearing for sale. Somebody obviously wants this one and is willing to pay for it! I wonder whether this auction will draw more WTs out of the woodwork? A high auction price is often an incentive to have a second look at a previously unloved object. This one looks complete and original and in fair condition. The earlier curved frame over the electromagnets bodes well for a high auction price. It should be relatively easy to restore.

GENT MASTER CLOCK WAITING TRAIN MOVEMENT on eBay (end time 23-Nov-09 19:37:38 GMT)

The auction was won with a bid of £2400! (UK Pounds)

Here is an image of an immaculate C40A:

http://www.flickr.com/photos/vrolijksclocks/43514719/

An image of an early C40A WT on legs which I found online years ago. If anybody claims copyright to any of these images, and resents their use on a non-commercial blog, I can remove them immediately on being contacted.

Another privately owned C40A, in complete and fine condition. Early enough to retain the curved frame over the drive electromagnets. Probably from just after the WW2 period.

A larger WT and pendulum from Flickr owned by onamission.org.uk

C40B(?) WT from Owens College, Manchester University before restoration by Symon Boyd.

Clock Restoration

A very early WT prior to restoration. It uses pivoted, sprung rods for the drive contacts. I have attempted to tidy up the "rather busy" image background using a virtual brush and PhotoFiltre software. Not with great success but it helps to expose the essential parts of the movement.

Pulsynetic C7 master clock, "bell ringer" contact device, charger and batteries with a WT over on the right. Does the bell ringer suggest a Pulsynetic bell ringing machine is active somewhere above? What is the purpose of the case hidden by the ancient wooden pillar on the left?

A larger WT movement in an English church. Possibly a C40B? It is hard to judge the true scale from the image. It shows features from around WW2. It is also remarkably similar to the bright green WT above. (onamission.org)

These last two images were copied from a website some years ago but which I have been unable to trace more recently. If you know anything about this system or any other WT installation do, please, get in touch. I would be grateful for any images of WT movements of any size. If you own or care for a WT please forward any images you have of the movement and any original Pulsynetic system components. Your privacy and anonymity are (of course) guaranteed unless you request otherwise.

chris.b(at)mail.dk

Left click on any picture for a larger image. Back click to return to the text.

Clock photography.

2008-08-14T15:01:00.000+02:00

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Just some personal observations on clock photography from several decades of activity as a hobby: Feel completely free to disagree or ignore my advice.

Photography of anything against a white background is very difficult because the camera is confused by the brightness of the background. You could try using a central spot option for exposure and focus in your camera menus. Otherwise you will usually get a very dark image totally devoid of detail. A large piece of plain brown packaging cardboard, plywood or hardboard as a background helps to bring out the fine details of any object. All thanks to the neutral colour, its low brightness and low surface reflectivity. Light-darkened natural pine boards and mat-painted plywoods also work well as backgrounds if not too light in colour, glossy or highly varnished. You might get away with a neutral throw cloth to kill the bright background if appropriate.

Distracting objects in the background are a real problem when sharing images online or with fellow collectors. A neutral background board or even a piece of neutral plain cloth can effortlessly hide a multitude of sins from the camera. Even quite a large board can be easily stored out of the way against a wall without taking up any room at all.

Here is an example of a distracting background almost concealing the detail of a fascinating early WT movement prior to restoration. I have only used it because I have no other image which better demonstrates this problem. This is certainly not intended as a criticism of the owner as a photographer. Not at all. I was very grateful for his images of such an interesting object. He had no reason to "improve" his images for my sake and it would have been rude to ask him to retake the pictures with a neutral background.

Five minutes with PhotoFiltre roughly painting out the background with a broad brush is not going to offer anything like visual perfection. But gives an idea of how a neutral background can lift an image of a technical subject. A board or cloth hiding the background when you are taking your own images will make your pictures look far more professional even for your own enjoyment. It soon becomes a habit to look at the background before taking any photograph if you practice for while, reminding yourself to check each time.

Below is an image of my WT sitting in the workshop with a rack of (very) untidy shelves right behind it. I simply propped up a handy piece of plywood behind the movement before taking the photograph. Then I cropped the image and gave it a slightly more flattering appearance using PhotoFiltre software. The enlarged image is full screen and 3o0KB so you may choose not to click on this particular image if you still have a slow connection.

Smaller objects can be captured in a cardboard box lid or wooden tray. I often use the greenhouse-conservatory for photographing small objects because the white roof blinds give a perfectly even light. Though only until I block the light with my head and camera. Sometimes flash helps even here. I usually try with and without flash and usually from a distance using zoom. Macro shots are often a difficult choice between closeness to the object, magnification required, depth of field and varying the zoom factor. The wonderful thing about digital photography is that you can can try every imaginable option in a matter of a minute or two and see the results immediately.

If flash is to be used then I find it is far better to move well back and use the zoom to frame the object. The flash then gets a chance to spread evenly across larger objects. The camera will usually adjust the intensity automatically for you. Avoiding head-on flash is best to avoid burnt out highlights on flat surfaces which directly reflect the flash back to the camera. Move slightly to the side to avoid direct reflections in glossy surfaces. Change the angle repeatedly and keep trying shots to see which works best. Often one would prefer to photograph a clock "face on" but it is rarely possible unless there is abundant natural light. Many clocks are often in poor natural light and require flash for any detail to be seen at all. I usually photograph master clock movements from a minimum of 3-5 feet away using flash and zoom to frame the area I want to capture. Capturing the entire case length of an English master clock or long case clock would require a very distant shot. Careful cropping with image handling software can be quite dramatic. Raise yourself to the height of the dial for best effect. Photographing a long case clock from a low viewpoint will often distort the appearance of the clock or its dial. The problem with being on the same level if that flash will reflect in the dial glass so try above and below shots to avoid a direct reflection. Distance helps too in spreading the flash as evenly as possible. Varnished or highly polished wood will often look quite ugly if the camera catches the light of the flash as a direct reflection. So keep moving about slightly and vary your distance if you can. Keep checking the screen or download your trial images if you are at home.

A distant view often suits turret clocks if you can pull back at all. Getting too close produces pretty shots of distinct areas of the movement but lacks the drama, detail and completeness of the whole movement. The human eye is far more skilled at zooming in than any digital camera. Taking close shots of such large objects inevitably throws large areas of the mechanism out of focus. A distant shot places almost everything in focus simultaneously. Provided of course that you can hold the camera still enough. Or use flash to do it for you where possible. Again using the zoom lens to frame your subject, taking several shots and carefully reviewing your results on the camera screen before leaving.

I always take twenty shots of an interesting object with a digital camera where only one would do with film. I keep moving around slightly between taking pictures. Final selection is then possible from large images on your computer screen to find the best obtained. Taking lots of photographs is a hard habit to break from film photography where the cost of processing and the limited number of prints per film made one far more careful. With film, one can never be certain that an object has been captured sharply and framed perfectly in the best possible light. Digital photography gives this wonderful freedom with almost instant access to the results on one's own computer screen. Or even, there and then, on the camera screen if it large enough to see anything useful.

If you are away from home then always review your images on the camera screen before moving on. You could save your embarrassment of having photographed a colourful subject in sepia or monochrome due to a clumsy touch of a button selection in the menu. A large camera screen is a huge advantage here. I took a number of photographs of a colourful cathedral organ with my brand new Canon digital camera. Only to find when I eventually arrived home that I had somehow selected a strange colour option of sepia monochrome with gold highlights! Hmm.

I like compact cameras with a screen almost the entire size of the back plate. Just make sure the entire screen area is active before you buy! Some camera makers cheat and have hidden screen frames which only appear when the screen is lit. Naughty! Better cameras seem to have much better low light ability and are reset to take the next shot far more quickly. Online and magazine reviews are invaluable here in selecting from the incredible choice of cameras on the market today.

I wish compact digital cameras were made much lighter and thinner to go in a normal pocket. Simply because I carry a camera with me everywhere. No doubt the retractable zoom lens makes the manufacture of thin cameras more difficult. Progress in the compact digital camera field is simply amazing with older cameras looking and feeling rather like clunky travelling trunks against the slim briefcases of the present crop of cameras. Metal may make a camera look better value or even more substantial but I'll settle for something lighter if possible. Heavy cameras are throwback to Nikon film SLRs which needed a sack truck or wheelbarrow to haul them about for any distance.

I have not dabbled with digital SLRs having spent decades dragging film SLRs around. The bulk and weight are a bore and quickly draw attention to the fact that you are using a camera in a public space. Such large cameras are threatening to many people. I now prefer digital compact cameras. Held at arms length they seem more of an extension to one's arm. One could simply be pointing out something of interest. People don't seem to notice or simply don't care these days. Holding a huge black SLR box up to your face with cannon of a lens hanging off the front is going to draw far more attention.

Hopefully organic screens will offer further improvements in weight and compactness as they have on mobile telephones. These camera phones are now driving the digital imaging market. No doubt the compact cameras will continue to enjoy a trickle down effect of the better features from the phones.

Do not allow your shadow or reflection to be seen your photographs. There is nothing worse than the sight of a grimacing photographer being perfectly reflected in all their gory detail in the glass of a clock case or dial. Except perhaps when the reflection of the photographer is inadequately dressed because they think they are invisible behind the camera at home on a hot and sunny day. Stand off to the side of flat glass to avoid being caught in the reflection. Or open the glass door if appropriate and where possible. Moving back and using the zoom lens (if you can) helps here too. Your light coloured reflection will often make the clock behind the glass completely invisible! While a dark background reflection will expose it in all its glorious detail. So look around for an angle which will offer a suitable reflection in the glass to make it appear transparent. A willing slave holding up a dark coat might work even better if you have both handy. Failing that dress completely in black like something out of a war action film and take your chances. Removing the gloves and balaclava after taking your shots will help to avoid arrest if you are out and about.

It is incredibly difficult to avoid reflections in convex glass. At home I have control and freedoms not available in the public space. I found that hanging a dark cloth off to the other side of the object and behind the camera allowed the glass to drop considerably in its reflectivity. This allows clock hands and dials to be seen clearly behind convex glass. A rather dark board pierced to allow just the the extended camera lens to peep through would no doubt allow a head-on shot of a difficult subject behind (even convex) glass provided flash is *not* used. A tripod would no doubt improve the chances of success considerably when using this idea. I haven't tried it yet but offer it as an idea.

Here's a clock for which Barrie needed an image for his online clock museum. I could hardly send him this one could I? I often use free software called PhotoFiltre to crop, resize and process my images from my picture files after I have downloaded them from my cameras. It makes so much difference to prepare one's images before posting them online. This excellent software has enormous potential to improve one's images without struggling up a steep learning curve. The screen process symbols are self-explanatory and easily followed. Any false moves are easily undone up to a number of stages backwards in the processing chain. Highly recommended for those unwilling to spend the time to learn to use professional imaging processing software. Not to mention the huge outlay usually involved. If you have free bundled alternative software in a package by all means use what you have available.

Exactly 100 images later and having tried every imaginable combination of lighting, flash, distance and angle, I finally had something I thought could "improve" with PhotoFiltre. I brushed out the distracting background and played with cropping, contrast, colour, gamma and brightness. I think you'll agree that it was worth the effort to capture the clock in its best light. Only the false pediment held real interest for this particular shot. The idea was to clearly show that the false pediment was a simple decorative triangle. The dial appears far more yellow/cream than it does in daylight but this is only a small point as it does not spoil the image. The wonderful colour of the polished mahogany is brought out quite well. It is hard to believe that this case had been painted with several thick coats of gloss white paint before it was purchased. I used a cabinet scraper to get most of it off. Then I applied many coats of button polish with block backed sanding by hand in between.

Backup your images regularly onto DVDs to avoid the disaster of a hard drive crashing. Mine has just died after seven years of stuffing it with images! Despite having a second large hard drive in the computer most were unreadable. With around 12 gigabytes of images stored on many unreadable sectors. I was (nearly) saved by a backup DVD of my images which I had quite forgotten about. Though I lost many hundreds of images from the last four months before the crash. I was far too lax about backing up my images onto disks. Because I had so many images it always needed at least two DVD RWs each time to cope with the sheer volume. As I take one of my compact digital camera with me everywhere I had built up well over ten thousand images. It is easy to forget about image backups and then lose images which can never be recovered. Nor retaken in the event of a hard drive crash. I never thought it would happen to me either.

Take images using the higher resolution settings in your digital camera menus. Larger image files do fill memory cards quite quickly but these cards are remarkably cheap and keep getting cheaper all the time. Buy two medium, rather than one huge capacity, memory card. Smaller image sizes simply don't stand up to enlargement. Which means all the fine details are fuzzy. Once taken, most pictures can never (ever) be repeated. One day you will want to read the fine print of the label, the sign, or the notice in the background of one of your images. Or want to examine an object you never noticed when you took the photograph. It is only after the event that you discover that fuzzy is just not good enough to be able to read the opening times of a museum, gallery or shop before setting out in the car on a long journey to retake your pictures in a much higher resolution. When you do get back there you find there is no sun, too much sun, it is in the wrong place, the trees have grown leaves or lost them, or the conditions have changed completely for some other reason.

Click on any image for an enlargement. Back click to return to the text.

Another WT.

2008-08-12T22:49:00.004+02:00

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These images were kindly sent to me by the new owner of a C40a WT movement. It is shown before any restoration has taken place. The small relay electromagnet on the left (which releases the gathering pallet at half minute intervals) is only missing because it had a broken tail. So it needed some "surgery" to ensure a good connection. Other than that the movement looks to be in very good condition indeed. The details of the movement suggest it was made some time in the 1940s.

This WT movement still shows the beautifully organic, early, curved shoulder to the mainframe over the drive electromagnets. Later examples have a straight, sloping section to the frame just here.

Here the Hipp Toggle damper can be clearly seen attached to the extreme right of the frame. A rubber hose on the end is supposed to touch the Hipp Toggle to damp its motion.

A view of the rear of the movement showing the worm and wormwheel in the foreground. An extension shaft from the wormwheel leads to the first bevel wheel which drives the larger crown wheel on top. The slotted universal coupling can be clearly seen in the foreground. A T-shaped casting would rest in these slots to drive the motionwork of a dial in line with this coupling. The slots would allow for the thermal expansion of the lead off rods with wildly fluctuating temperatures normal for tower clock installations. Without some longitudinal freedom the lead off rods might buckle or bind as they expanded in summer temperatures. Note the glorious deep gold of the original, lacquered brasswork.

The right side of the WT movement with "ELECTRIC" cast into the metal of the frame. The compact dimensions of the very powerful WT movement are clearly seen here. A weight driven movement to drive the hands of four 6' dials would have been considerably larger in all dimensions. Not to mention the bulky weights and the vertical room they needed to lower themselves. To drive the clock movement for as little as a few days or only up to one week.

The Waiting Train end of the WT movement with its controlling relay electromagnet removed. The relay electromagnet's support plate is still present. The heavy pendulum bob on its stub shaft has been temporarily removed while the WT movement is restored. "PULSYNETIC" is cast into the main frame on this end. This was a trade name for Gents' public timekeeping products.

A more general view of the rear of the WT movement. Two bevel wheels appear to be missing at the front and back of the crown wheel support block. Including the forward facing one which usually carries Gents', the makers name, "Pulsynetic" and a time setting dial. The original time pointer remains as do the work-polished stub axles for the missing bevel wheels. Not all WTs were made to drive the hands of four dials. In this case it seems all the parts are present for four dials except for the two bevel wheels themselves. Though WT spares are incredibly hard to find new replacement bevel wheels are not impossible to obtain. Even a good copy of the time setting dial can be engraved to order using an existing example.

The large, drive electromagnets with the hinged, rocking armature on their right. A roller on the top of the armature engages with the extended hook of the pendulum rod just above. This engagement only occurs when the large, drive electromagnets are energised at intervals by the Hipp Toggle and V-block. These parts act as a simple and reliable minimum arc sensing switch for the pendulum. The ingeniously simple Hipp Toggle and V-block were invented by Matthias Hipp, a German clockmaking genius somewhere around 1843.

The rear of the pendulum, ball bearing, support case is clearly seen here along with the bifurcated top to the pendulum rod. Using two, long life, ball bearing races instead of a potentially fragile, rusting suspension spring was only possible thanks to the unique design of the WT. Since the WT pendulum has no duty of precision timekeeping any variation in friction of the pendulum support bearings has no importance at all. Normally, weight driven clocks rely heavily on friction remaining completely unvarying to ensure good timekeeping. The ingenious WT passes its precision timekeeping duties over to the master clock which controls it. Variations in arc and frequency of impulsing are completely irrelevant in the WT design as far as timekeeping is concerned. Thanks to its worm gearing and powerful pendulum drive electromagnets the WT is really a very low speed, high torque, electric motor. The master clock provides the half minute impulse which restarts the Waiting Train mechanism and thus the drive to the clock hands. Maintaining an accuracy for the exposed clock hands of as a little as a second per week. Or even less.

Click on any image for an enlargement. Back click to return to the text.

Another early Gents' C40A WT.

2008-08-11T08:43:00.017+02:00

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An appeal for WT images on the UK based electric clock forums has produced some excellent WT images. I have reduced the originals slightly for the blog format to avoid long downloads times on slow internet connections. Resizing only takes mere seconds in PhotoFiltre. (a free, image handling, software download which I use a lot)

This movement is almost identical to my own. Though with a slightly earlier serial number of 282 against my own 309. Suggesting 1930s manufacture.

In its un-restored condition it looks as if has been painted gloss black. Interestingly, the lower pendulum rod shows that it was probably once the same marine, green-blue as mine. Though it is just possible that the pendulum is a later addition. Early WTs were indeed painted black. It is impossible to tell from this distance which colour is original. Unfortunately I don't have a manufacturer's changeover date to green-blue from the earlier black.

The movement is still covered in polystyrene packaging dust and has obviously just been set up for testing. Hopefully on 20V DC. The owner has stated that the movement is still in unrestored condition. This early movement has the pretty, deep-lacquered, brass details. Later models had plated parts. The sinuous, organic curve on the right of the main casting is indicative of an earlier movement. It looks to be in fine condition but just needs a gentle clean.

Rear view from above showing that the usual bevel gear cluster is absent. This is the second WT I have seen with bevel gears missing.

I hope to try making some bevel gears in my lathe when the workshop finally warms up. I have a Wilding book with instructions on bevel gear cutting.

If you know of anybody who offers to make bevel gears to order, in brass, do get in touch with me. I can then post the information here. Even without bevel gears the WT can still drive the hands of two dials set in direct line with the wormwheel shaft. All it needs is universal couplings and lead-off rods.

A lower view from the rear. The spark quench is visible in the foreground. The large, green, pendulum drive electromagnets are green like my own. These can be nicely restored using odourless lamp oil. Then given them a bath in washing up liquid and hand warm water to neutralise the action of the oil. If the oil is simply left on the protective wax it may eventually dissolve it.

Front close-up. The hand setting crank could be made to look more original with a pepper /salt mill crank with hardwood knob. Sadly the absence of bevel wheels also taken away the maker's, signed, time setting dial. Though a time setting crank is still very useful for rapidly resetting the movement or clock hands to time.This movement still has its original Hipp toggle damper on the extreme right.

Movement end view showing Gents' "Pulsynetic" trade name cast into the main frame. Just below are the terminals for connecting the time series circuit and 20V DC power supply for the drive electromagnets.

The waiting train mechanism in close-up. Note the robust construction for a very long and reliable life. The time circuit relay electromagnet is at lower, centre left. This releases the WT movement from its locked condition on the arrival of the accurate time impulse form the controlling master clock. Without the master clock the timekeeping would be hopeless. Connecting a master clock to a robust and powerful motor pendulum was the death knell for weight-driven turret clocks.

Close-up of the 120:1 wormwheel and worm reduction gear. This was one of the secrets of the WT's immense power. Most clocks drive the hour hand with heavy weights. With consequent friction and much reduced torque to the escapement. The WT drives from the fast end of the train with considerable torque amplification by the time it reaches the hour shaft. Moreover there is no friction to speak of. Certainly not as a result of gear teeth losses and heavily loaded plain bearings throughout the train. This explains the power of a WT to drive much larger hands than any weight-driven clock of its own size.

A nice, clear, close-up of the contact assembly and Hipp Toggle and V-block. The absence of lacquer to the contact support bars suggests it has been stripped for some reason. A coat of dark gold, cold brushing lacquer will make a fair job of reproducing the original finish. I ought to do the same to my own WT. Which required a complete new contact assembly to be made from scratch.

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The following images were provided by Paul Strickland:

Only later did I realise that this was the same movement shown above.

The long brown coil at bottom left is presumably a second spark quench, wire wound resistor.

Click on any image for an enlargement. Back click to return to the text.

And another.

2008-08-10T19:16:00.003+02:00

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Paul Strickland of Onamission kindly provided some images of a C40A identical to my own:

Front view with the massive pendulum bob alongside.

Rear view. Complete in every respect. It looks indistinguishable from my own WT movement.

It would be interesting to discover the serial number of this one. If the owner would care to get in touch I can add the number to my tiny WT database.

Finally, a fascinating collection of parts laid out from a later C40A. Probably post WW2 judging by the pale grey paint, plated parts, the electromagnet coil wrapping and the pressed form of the contact, steady bars.

WT Bevel Wheels

2008-08-05T22:12:00.014+02:00

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It has come to my notice that a number of C40A WT's lack one or more bevel wheels. Some lack a crownwheel too. It should be noted that not all WTs will have driven four dials originally. Though owners of WTs might well wish otherwise. If only for appearance sake. Even if they do not plan to build themselves a four dial, clock tower on their house or outbuilding.

Four dials may need bevel wheels, leading-off rods and motion work for each dial unless the WT is raised up to dial level. Which might be a shame, if not easily accessible. Because one cannot enjoy watching the WT clock movement in action. An alternative is a single vertical lead-off rod and a raised, crownwheel gear cluster at dial level. Though you may not want your WT in the middle of the room. If placed against a wall a further two pair of bevel wheels will drive the raised cluster via further leading-off rods.

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I have contacted four potential UK sources of bevel wheels (March 2011) but none has responded as yet. (I will, of course, update if this should change)

Note that all images can be enlarged by clicking on them. Those on a slow connection might want to avoid doing this. So I have sized these "thumbnail" images appropriately. Making them all even larger would mean quite a long download time for some visitors.
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As a service to those lacking bevel wheels I have carefully measured my own with a vernier calliper. Then appended the dimensions to some images which I have taken specially for the purpose: First a couple of older images:

The crownwheel bevel cluster in place on the back of the WT movement.

A close-up of the four bevel wheels meshing with the larger crownwheel on top. The crownwheel has to be larger than the lower bevel wheels or the cluster would be completely locked by opposing teeth all meshing simultaneously.

Strictly speaking these are mitre bevel wheels since they meet at 90 degrees. (wheel is the normal horological term for a gear wheel to differentiate them from cruder engineering gears) The bevel wheel on the right in this picture is the first wheel and drives the crownwheel. The crownwheel then drives the three remaining bevel wheels. A coupling on the far end of the rod driving the first wheel provides drive to the fourth dial.

The crownwheel cluster seen through an aperture in the WT main casting. The two large bolt heads, below the hand setting dial, hold a supporting casting for the gear cluster. This is an early shot taken soon after obtaining my WT. When some missing parts had yet to be fabricated. The dial pointer and Hipp toggle damper are both missing here. These would be held by screws in the open, threaded holes near the bolt heads.

The gear cluster from the front with the forward facing wheel carrying the hand setting dial. Ignore the rather crude (temporary) dial pointer. It is a great shame when the gear cluster is missing from a WT if the hand setting dial is also lost. A dial engraver should make a good job of a replica if bevel wheels can be obtained. Some clever computerised engraving or milling machines could also reproduce such a dial.

The bevel wheel support bracket removed from the movement. Provided the top support block fits in place on the movement the black painted casting is not strictly necessary in this fancy form. Meaning that a simpler block could replace the casting. One could saw out something from a solid block to provide clearance. This would achieve the necessary offset and supply a stable platform for the bright metal, stub axle block.

The gear cluster and casting from below. The forked objects at the bottom and left of the image are couplings or universal joint for leading off work. A T-shaped crossbar fits in the slots and drives a rod or tube leading off towards the dial work. The long slot allows for length variations due to thermal expansion of the leading-off rods.

Note the clearance between the bevel wheels provided by the larger crown wheel. The teeth at the meeting edges of the bevel wheels are travelling in opposite directions. So would lock up if they actually touched.

Dimensioned bevel wheel.

Dimensioned bevel wheel 2.

Dimensioned bevel wheel 3.

Bevel or crownwheel wheel cluster seen from the bracket face which mates behind the WT main movement casting. The two diagonal holes are for locating or steady pins. I have removed the original, forked, universal joint from the face of the dial since I need no leading off work in this direction.

Dimensioned crownwheel bevel gear. The rod shown is simply to support the wheel on its edge for taking the photograph.

Dimensioned crownwheel 2.

Dimensioned crownwheel 3.

The support block for the bevel wheels.

Bevel wheel block inverted. This component looks to be hard chrome plated.

The complete bevel cluster component
count.

WT Hand setting dial. It should ideally be re-silvered and clear lacquered to ensure maximum clarity in poor light. I have run out of old-style silvering salts. Which produce a much whiter and clearer silver than the more modern "burnished stainless steel" look of today's, cheaper, silvering salts.

Here's the hand setting dial after re-silvering. A bit bright for my taste. An effect which is reinforced by the 500 wet-and-dry spun graining. Still excellent legibility with good whiteness.

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An old, brass-dial clock with a modern silvered dial (or chapter ring) looks completely wrong. It ought to have been re-silvered with the whiter and more expensive 18th century salts. Producing a very high contrast, matt, silver-white against the very black, wax-filled numerals.

This finish, along with the dark, blued-steel hands was developed specifically for very poor, indoor lighting conditions. Typical of most houses of past centuries when window glass was hand made and very expensive. Only candles and oil lamps were available to check the time at night. Which is why loud striking was so important to a household. Bedroom clocks were strictly for the rich.

A modern, shiny silver finish reflects the contents of the room regardless of viewing angle. Greatly reducing contrast and legibility of time reading dramatically. The worst silvering powder produces a finish which is actually bluish as well as too shiny. The hands often seem to disappear against such a shiny dial. At its worst a modern silvered brass dial can even look like polished and printed aluminium.

On a safety note: Do not warm an old brass dial without it having had a bath in clock cleaning solution. The effects are extremely toxic if you apply heat to an old and dirty brass dial!

The irony is that it is not strictly the "done thing" to clean the back of an old dial. Something to do with proof of originality, I would imagine. Given the large numbers of dial and movement "marriages" in the antique clock trade it may be simple paranoia. A dirty dial plate can hide old, patched pillar holes.

I have been caught out a couple of times while warming an old brass dial plate or chapter ring for re-waxing the numerals. The effect feels exactly like having one's lungs collapse suddenly and catastrophically! I have twice had to take to my bed to recover! Avoid at all costs! Rinsing has no effect on an old dial! It must be cleaned properly to avoid toxic fumes. You might try working outside. Or with forced air extraction. Still risky!

Click on any image for an enlargement. Back click to return to the text.
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Loudness of popular, collectable, electric clocks:

2008-08-04T11:19:00.020+02:00

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Gents' C7 Pulsynetic............................81dB(C)....78dB(A)

Synchronome 1920 no GA buffer..........74dB(C)....70dB(A)

ECS double contact.............................76dB(C).....70dB(A)

Gents' WT C40A 20VDC.......................80dB(C)....80dB(A)

Synchronome turret slave No4...............75dB(C)....73dB(A)

PO36 below background noise. The slave dials predominate.

Background noise level ~55dB(A)

All masters were mounted on a 4" breeze block wall.

All measurements made at ~1' (30cm) using a Galaxy 140 digital SPL meter using Max Hold. C-weighting records deeper sounds and is more typical of human hearing. A-weighting is generally used for noise measurement but does not favour the lower frequencies.

Lowering drive voltage is a popular way to reduce noise with all electric clocks provided reliability is maintained.

The pendulum drive predominates in the sound picture of the WT. Frequency of drive impulsing will depend on the load. Up to two minutes between impulses is possible with a lightly loaded / rigidly mounted WT movement. It might be possible to damp the sound slightly with rubber buffers to the armature. This may require undesirable modification! There is very little room to play with.

Further experimentation has produced a very major reduction in WT noise levels. In the past, even the thinnest bicycle inner tube had proved much too thick as an electromagnet buffer. This had been a major stumbling block to noise reduction since obtaining my WT.

Today, a humble rubber band was simply stretched around the rocking armature. The band intervenes between the electromagnet cores and the armature. Thereby stopping the very noisy metal-to-metal contact completely. If the rubber band wears out then another can be easily slipped in its place without dismantling anything. Absolutely no skill is required. Just watch your fingers if the pendulum is still swinging!

Stopping the heavy and powerful pendulum is a very good idea while working on any WT. Otherwise the pendulum could easily cause severe crushing injury to the extremities!

Damping the fall of the armature, height-adjusting screw is also important in noise reduction. The screw adjustment ensures that the impulse roller does not run continuously on the underside of the pendulum hook. However, the domed screw head falls heavily in metal-to-metal onto the WT's mainframe casting.

By raising the screw sufficiently a rubber pad can be placed under the rounded screw head. This rubber buffer can be glued to the WT mainframe with contact cement. Something like bicycle, puncture repair, rubber cement will do. A small, plain, rubber, tap washer would suit perfectly. You must use glue or the tap washer will quickly fall off. Clean the frame locally before applying the contact glue. The paint may be greasy.

It is an essential part of WT set-up that the impulse roller just clears the underside of the pendulum impulse hook. Too much clearance leads to a loud metallic clonk as the roller finally catches up with the pendulum hook. Close roller clearance ensures a quiet take up and strong push over the maximum possible distance.

The armature, height adjusting screw is a tight friction fit in the armature but amenable to pliers. The nut is permanently fixed so leave well alone. Removing the front bearing block allows easy armature removal. The rear bearing can be safely left in place.

By such very simple means a WT can be made almost fully domesticated from the noise point of view. The sound of the Hipp toggle now predominates. One must hope that the rubber band does not wear out and snap in the middle of the night! Nothing untoward will happen but the noise levels will probably quadruple!

The thickness of the rubber band is not particularly critical. Though its length may affect its lifetime if stretched too tightly. Apply thinner bands to taste but ensure the pendulum receives a decent push to achieve a reasonable period between drive impulses. The angular nature of the armature movement will dictate whether a rubber band is too thick. Avoid oil as it will quickly degrade the rubber.

My WT showing the position of the rubber band (orange). The position of the tap washer buffer is arrowed in red. The rubber washer sits under under the head of the armature height adjustment screw. Where it normally rests (metal to metal) on the main frame. (better picture to follow when my TZ7 camera is repaired (again!))

The WT toggle damper is also useful in obtaining further noise reduction. I used silicone rubber tube on the end of the damper rod to considerable effect. Old, hardened, rubber tube will not achieve much in the way of noise damping.

Tolerance of noise is highly personal. Even the quiet tinkle of a Hipp toggle on a PO36 can drive one to distraction when trying to sleep in the room above.

As a background noise to other daytime activities the sound of master clocks is soon forgotten. As is witnessed by master clocks frequently being fitted in manager's, headmaster's and supervisor's offices for security.

Click on any picture for an enlargement. back click to return to the text.

Links

2008-08-01T10:15:00.002+02:00

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Here are some excellent websites dealing with Gent's Clocks and Clock Systems. Rick's website deals with the master clocks themselves with lots of very useful and practical information for carers and collectors:

Gents' Pul-syn-etic clock

And here is the website of an acknowledged Gents' collector, expert, master restorer and a superb illustrator. A huge range of items produced by Gents related to timekeeping and their impulse clock systems are beautifully displayed. Others can only marvel at the skills and encyclopaedic knowledge of this remarkable horologist.

http://pulsynetic.eu/

Here's another superb website dealing with a wide variety of master clocks.

Electric Master Clocks

Here's a comprehensive links page on an interesting website:

http://www.remmepark.com/manchesterclockworks/links/links.html

Here is a link to the website of a genius at clock movement animation: Have a good look around. You may need to download Adobe's "Shockwave" Player to enjoy the animations.

Shortt's free pendulum

Expert, electrical horologist, Martin Ridout's web page on the Pulsynetic master clock. (amongst many others) With some really excellent images: Have a good look around while you are there:

Gents Pulsynetic master clock

Another Martin, who looks after a partial, Pulsynetic clock system. Which originally had a number of slave dials including turret slaves, a battery set, a contact programmer and a bell striking machine: Rare images of an existing system in situ. Sadly a number of original items were stripped out before Martin knew of their existence. The bell ringer has been restored and is now working:

Electric Impulse Clock Systems
Dead link.

Including a web page with a remarkable collection of slave dials:

Electric Impulse Clock Catalogue
Dead link.

Back click from these websites to get back to the text.