Introduction

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The starting point of my original WT blog: From here on the posts run logically. Rather than the chronological reverse typical of most blogs.

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.

Sorry. The original link no longer works.

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.

Sorry, another dead link. It is 14 years since I posted this.

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

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The WT Pendulum

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Let us 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, through all the parts, were bored oversize. Then model aeroplane, plastic fuel tubing was slid over the long screws during assembly. This ensured electrical isolation of all the various parts from each other.


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 upwards, to follow the curve of the cast hook, it gives a push to the pendulum.  Allowing it to continue swinging for another 20-60 seconds or even more under light loads. 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 via the armature roller.

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 like a parent. It will continue pushing its pendulum for decades unless the electric power supply is interrupted.

Another view of the pendulum drive electromagnets, rocking armature, impulse curve and roller pallet.

Note how the under surface of the "hook" is curved to almost follow the radius from the pendulum suspension pivot point. The difference in the curve from a true radius allows the roller to apply a push to the pendulum without jarring. Were it a true radius it would be a "dead" surface and no push would be applied.

Such dead surfaces are used in some mechanical clock escapements to avoid variations in friction between sliding surfaces. The "corner" is the point at which the roller is freed from its upward pressure against the impulse surface. The Hipp toggle contacts will then open and the armature will fall back again due to gravity.

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 'maintenance' impulsing. This clever power demand compensation was a remarkable breakthrough.

Most mechanical clocks have no answer to greater loads on the clock hands. The drive weights are simply made heavy enough to overcome any likely resistance. Which is wasteful and applies too much pressure when the clock is lightly loaded. If the weights are reduced the clock risks stopping in a storm. Some clock keepers increase the weights in winter and reduce them in summer.

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. (journal bearings) 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 completely 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 colder, northern environments.


The hand wheel has a very clear message on its face: Turning the handle occasionally, at random redistributes the grease and avoids localized 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 dial, 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, or rusted 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 always allow a little freedom along the length of the rod. So a stuck bearing will prevent this normal free play.

The temperature differences, between summer and winter, can only be imagined in an unheated roof space. Being made of metal, the lead-off rods would gain and lose considerable length with ever-changing temperatures. Meanwhile, the stone and timber building remains largely unmoved. The relative movement must be accommodated between the clock movement and the exposed clock hands. A practice long established with weight-driven clock movements over the previous centuries. Though modern expansion links would be mass produced. Rather than made as one-off items forged by a blacksmith.

Click on any image for a larger version.

Back click to return to the text.

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The Waiting Train Mechanism:

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(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.

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

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'WT' Dimensions and electrical requirements.

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My C40A Waiting Train movement dimensions:

Approximately 425mm (16.75") wide across the feet.

387mm (15.25") high from the underside of the feet to the top of the pendulum suspension casing. The suspension bearing hand wheel is very slightly taller.

Approximately 190mm (7.5") deep. The feet themselves are 150mm or 6" deep. (front to back)

The flat bottom of the pendulum bob extends a further 42 cm (16.5") below the underside of the feet/surface on which the movement rests.

The total overall height from the top of the movement to the flat bottom of the bob is 80cm. (or 31.5")

Later models of the C40A may vary from these dimensions. The main casting took at least two distinct forms over time. Larger models at least three forms.

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 pendulum 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. Care should be exercised when undoing the two screws which hold the bob and lower half of the pendulum rod. The bob is quite heavy and could cause serious injury or damage if dropped.

I loosen both screws. Then remove one screw completely before undoing the second screw carefully by hand. Meanwhile, the bob is supported with the other hand. Or [better] a solid object placed under the bob to take its weight.


Note that the top half of the pendulum rod extends beyond the surface on which the feet rest. The rod must be allowed to enter the slot provided in the bench top before the weight is taken on the cast feet of the WT movement. Or two battens provided to allow the rod to clear the supporting surface.

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 (timekeeping) 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. Completely coincidentally No 309 was made in about 1939. Do not try to date a movement from its number in this simplistic way.

Note the heavy wax coating to protect the many turns of insulated copper wire of the electromagnets. 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 silk/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. Without the 1/2 minute impulse the WT runs far too fast.

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 switching 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 adapter," wall wart or similar Power Supply.

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 Adapter" 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!

There is a very real danger of overheating if the Hipp Toggle is badly adjusted. The toggle can rock back and forth while depressing the contacts tightly together. This must be avoided!

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

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'WT' Videos

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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 "steady-cam" stabilizer having become bored with the rather static view from a fixed tripod. The mass of the video tripod certainly stabilized 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.

The Pulsynetic C7 Master Clock

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

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 (large) or pinions (small)) 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.

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. Brass studs are provided on the clock case for this very purpose.

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 absolutely nothing for granted where the verticality of walls are concerned!

A decent, tubular aluminium level costs very little these days and is a good investment if you want the best from your master clock. Check the level's accuracy before leaving the tool shop by checking the floor and a wall carefully. Then simply 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:




Remember that Gents impulse clock systems normally run on 0.22 Amps. A minimum of 0.17A and maximum of 0.27A are tolerated. Low currents may make the system sluggish, unreliable but quieter. Higher currents can make some components rather/very noisy!

The voltage required to achieve this current will vary widely and will depend entirely on the resistance of the complete series clock circuit including any accessories. The safest method is to employ a digital multimeter and actually measure the current. The variable resistance (wire-wound potentiometer) in the master clock can then be adjusted. Or the power supply voltage increased or decreased to bring up the amperage to the correct level. Original impulse clock systems would mostly have used banks of batteries on trickle charge for reliability and independence from power cuts and variations in supply.

C7 circuit diagram kindly supplied by GV of the Netherlands.

Today's collector may use more modern batteries again on trickle or occasional charge. Fuses should be fitted on both sides of the battery to ensure greater safety. Many batteries can easily bring a connecting lead to red hot in the event of a dead short. Some clock owner use "wallwarts". Box-like mains plugs with voltage droppers and rectifiers to provide a suitable DC voltage for the clock or system. These use more power and may cost more to run over longer periods than occasional charging. They may also "droop" under load. Providing a rather sluggish reset on the master clock. Some of these small power supplies also get rather warm!

Where DC system voltages rise high enough to be a nuisance, then the clock circuits and/or accessories should be split into individual circuits. Gents components were available from the Pulsynetic range for this very purpose: From simple relays in boxes to complex, multichannel distribution boards. The avid collector can go on adding Gents "accessories" as and when they cross his path.

http://www.electricclockarchive.org/ClockGallery.aspx?moid=8808

http://pulsynetic.eu/power-supply/

http://pulsynetic.eu/other-devices/distribution-board/

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

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