Rempe self-winding - questions on electrics

flynnr2

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All,

I have a Rempe self-winding clock, the mechanism itself is running fine but have a few of questions on the electrics.

1) Arcing over the years appears to have burned a hole in one of the contacts which completes the circuit to tension the spring (see attached photo) - any recommendations on how to best remediate that?
IMG_0089.JPG

2) The electrics in the Rempe does not have a resistor to cope with flyback current and arcing (hence the problem above presumably). It seems sensible to add one as it can be done in a transparent and easily reversible way. I've read the various threads on resistors, diodes, & varistors but have a few additional questions:

a) The electrics engage every 6 - 7 minutes, so that is approximately 81,000 times per year. Is that a concern for varistors (there were some allusions to their performance degrading over many cycles)?

b) I am not sure how to appropriately size either a diode or a varistor and would appreciate any and all help. The relevant inputs I believe are
- 0.6 ohm resistance across the coil
- 3.3 volt battery supply
Which gives 5.5 amps & 18.15 watts to contend with.

Cheers in advance,

Rick
 

etmb61

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I'm not familiar with your clock, but typically there is a contact button of some sort riveted in the end if the leaf spring for the actual circuit. That looks like too perfect a hole for arcing.

300px-Mechanical_relay.jpg

Just saying.

Eric
 

sophiebear0_0

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Rick

I'm not familiar with the Rempe. Does it work on a similar principle to the Barr/Poole clock ? These clocks use a Hipp Toggle to energise an electromagnet to lift a weight. These typically "wind" after 30-40 seconds. These use silver buttons to act as electrical contacts.

I am not sure there is a true consensus on the best method for arc suppression on electromagnetic clocks. You often see diodes fitted in Eureka clock - though these are obviously not part of the original design.

ATO clcoks (the model without self-wiping contacts) actually used a resistor as part of the original design. The shunt resistor was typically 5000 ohm with a coil resistance of 1200 ohms.

There is an interesting article by Rob Elliot which discusses the pro's and cons of various repression methods. He recommends a resistor in the order of 10X the coild resistance (Spark Quench)

I would be interested in seeing some more details/photos of the Rempe clock once you get it sorted.

Best regards,

Peter
 

flynnr2

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I have never seen one of these movement, nor is there evidence of a rivet which has fallen out rattling around in the case, so open to suggestions - certainly the perfect circle could have held some sort of riveted contact at some point.

A more detailed picture of the contacts
- the tensioned spring causes the plate on top of the coils to pivot up
- which ultimately releases the spring steel(?) on the left
- to connect with the brass rod on the right
completing the circuit

IMG_0085.JPG
 
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flynnr2

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Another photo found online (auction site) - difficult to tell precisely, but does look like a brass contact rivet in the contact on the coil side.
17666_D.jpg
 

Berry Greene

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What a coincidence! Yesterday I bought an electrified wind to a balance regulated clock in a charity shop. It was filthy inside & out. I have given t a good clean and the movement is working when the spring is powered.

I don't want to teach my grandmother how to suck eggs here but I will just say there is a miniature electric motor attached to the Swiss 7 jewelled mechanical movement that is called each hour to re-wind the remontoire (is it?) that powers the clockwork. There is no sign of any spark suppression.

This is a DC circuit until the switch opens or closes. The motor is inductive and therefore we have high inrush currents and BEMF to contend with. This causes higher voltages and instant currents that can go way beyond the quiescent running condition. AC components both remove & deposit material from the contacts but the DC is all one way which gradually erodes the contact points - just like an old fashioned car with coil & points. A capacitor fitted across the contacts at least provides an ac by-pass path.

A diode can also be used as a "catcher" to restrict the extent of the voltage peaks. It might need to be a Zener diode or better still a form of Varistor. I don't know of any in the low voltage range. Anybody? I do know they aren't particularly reliable but then again they are usually operating with much higher voltages (in my experience).

This is an issue which I had not considered until I came to this thread of the Forum. I was just interested to see if anyone else had posted anything on this kind of electrification. I also wondered what sort of date you might put on a clock like this? The case is made from heavy gauge real brass IMHO. It had been lacquered although I had to remove it to stand any chance of cleaning it up. I will probably wax it rather than re-varnish it.

I have taken a few pictures. I'll post them when they have been downsized to a suitable size for transmission.

Best regards, BerryG
 

Berry Greene

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Fr mvmnt Rear motor Reg adj Motor o/p drive
Electric mantle clock - (7).jpg Electric mantle clock motor-2.jpg

Cam switch LH - Mainspring wind gear Motor at rear mvmnt front
Electric mantle clock mvmnt-3.jpg Electric mantle clock mvmnt-4.jpg

Assembled & cleaned Rear with PP3 battery
Electric mantle clock - (11).jpg Electric mantle clock - (10).jpg

Dial cleaned up
Electric mantle clock dial-1.jpg

I have one concerning question:- When battery is tired the motor stalls with lowered current running until battery finally discharges. This means heating of motor coils. I wonder - is this injurious? Would a re-chargeable be better choice where the voltage drops off a cliff? Just a thought. Anybody know what was recommended here?
Rgds, BerryG
 

sophiebear0_0

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Berry

Thanks for posting the photographs.

Looks to be an interesting clock - and a good spot on your behalf.

The issue of shorting the coil on a low battery is interesting. I don't know the answer. I do however own a number of battery driven remontoire clocks (Reform-type) that potentially suffer from the same potential issue. Low battery power can be insufficient to operate the kick wind and it ends up with current passing through the solenoid, potentially causing local heating as the battery drains. In practice I have not suffered any incidents, and my main line of defence is to change the batteries on a regular interval.

I am not convinced that using a rechargeable battery would make a great deal of difference in practice. Although as you say, the coil would experience less sustained heat as the power dissipates more rapidly.

My guess on age of your clock would be 1970-1980. There is an very good article by David Read (AHS 2011) entitled "The Electric Remontore". He mentions that the electric rewind was usurped by direct balance impulse / quartz around 70 years after the first introduction of the remontoire movement. The early ones were introduced around the beginning of the 20th century.

Sorry I can't shed any light on your clock. I look forward to hearing from others who may have something more detailed to offer.

Regards,

Peter
 
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Berry Greene

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Wow Peter!
Thanks for that response - very uplifting.
And the article you quoted is really a treasure to supplement the clock.

It's going well BTW - some slight regulation to the rate needed perhaps. Gains marginally.
When I have a better idea of what to expect by way of battery life I will post again to complete the picture. My Ni-Me-Hy PP3 has a 200mAh capacity. It doesn't sound very much does it? I can tell you that the motor takes 35mA (peak) and lets say it runs for 2 secs every hour (or 48 seconds a day). That's somewhat less than 6 hours of winding. The intermittent use plays to our advantage here giving the battery recovery time.
From that I get an expectation of 428 days. {Subject to verification and actual experience}.
I did read a "400 day" description of a similar clock. Seeing the 1970 time-frame for the production it seems likely it would seek to compete with the torsion "anniversary" variety I suppose.
Hey! How about a solar panel to boost the battery? Perpetual motion doth approach us!
Thanks again for your interest.
Best regards, BerryG
 

sophiebear0_0

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Berry

By way of comparison, I have just checked the resistance of the solenoid on the Reform. I get a value of around 10 Ohms, although I'm not very confident on my meter at such low resistances. The clock uses a 4.5 volt supply, so at 10 ohms would be drawing around 500 mA. So the power would be around 2 watts, compared with around 0.3-0.4 watts for your clock. The Reform contacts trigger about every 7 minutes, but the power-on time is obviously very low.

You can buy high capacity pp3 batteries which are around 800 mAh.That said, its probably better and cheaper to stick with the conventional power battery and change it more frequently.

Regards,

Peter
 
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Berry Greene

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Peter that doesn't sound right to me. Even a short blip of such current from a PP3 - nope unlikely. A rechargeable will do it mind but it sounds wrong.
There's one thing to remember here. The DC resistance is not the same as the ac ohms (more properly called Z for impedance). Coils revolving in magnets produce a large BEMF (back voltage) because such a motor is in fact also a dynamo. So the inrush current might be very high but it is opposed as soon as the motion starts and falls back very quickly. Strange as I suppose that sounds!
Another allied issue. If you were measuring the ac current into the motor (some meters will do but...…. See below) it would rise with the load. The more work you ask of it the higher the current (Watts) will be.

NOTE: The meter measures the current by actually measuring the voltage drop across a shunt resistor. This is in series with the supply and will reduce the applied voltage. By how much depends on the shunt value and the actual current. I hope that is making sense. The problem is that the full voltage of the battery won't be applied. Yes you can get a very good idea - so longs as the motor still runs BUT it will have an error. The best multi-meters have very low resistance shunts for this reason.

Regards
BerryG
 

sophiebear0_0

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Berry

You may well be right. As I say, I do have doubts about my cheap multimeter ! I have only tried measuring the resistance of the coil, rather than actually the current through the circuit when powered.

The Reform clock just operates a solenoid which kick winds a small mainspring. You can definitely see sparking as the spring winds down and the contacts approach closure. If the contact gap setting is not correct, it is possible to get sustained sparking. The clock then sounds like a buzzer.

Unfortunately I am not aware of any detailed technical specifications for the Reform type movements. Great if anyone else can chip in with some details. My experience is that the Reform movements are not very forgiving when the battery voltage falls below the design voltage of 4.5 volts.

It will be interesting to hear if anyone else on The Forum has come across your clock. I've done a quick internet search - but can't find anything.

Thanks again for sharing the info. Very interesting.

Best regards,

Peter
 
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Berry Greene

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Erratum. Slight error in my last post which I am now unable to edit. In the paragraph beginning "Another allied issue" I have written "ac" when of course I really mean "DC" - even though it may not be steady current starting with a "spurt" or inrush current to get the motor started. In this respect BTW a "motor" includes a solenoid. In fact sometimes certain types of solenoid are actually called a "linear motor."
Another useful feature some multi-meters have is a "MAX" or peak lock. This freezes the maximum reading seen since you press the button. I have used it with great success when measuring the starting current of my car battery. For that though you need a clamp type device which is hooked around the battery cable. It converts huge amps to mV and you use the multi-meter to read its output.
Hey I am way off topic. I think a fine is in order! Sorry about that. Yes of course I will pay up. :<))
Regards, BerryG
P.S. I am loving that link you posted on electric remontoire clocks. Great stuff.
 
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Berry Greene

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Berry

You may well be right. As I say, I do have doubts about my cheap multimeter ! I have only tried measuring the resistance of the coil, rather than actually the current through the circuit when powered.

The Reform clock just operates a solenoid which kick winds a small mainspring. You can definitely see sparking as the spring winds down and the contacts approach closure. If the contact gap setting is not correct, it is possible to get sustained sparking. The clock then sounds like a buzzer.

Unfortunately I am not aware of any detailed technical specifications for the Reform type movements. Great if anyone else can chip in with some details. My experience is that the Reform movements are not very forgiving when the battery voltage falls below the design voltage of 4.5 volts.

It will be interesting to hear if anyone else on The Forum has come across your clock. I've done a quick internet search - but can't find anything.

Thanks again for sharing the info. Very interesting.

Best regards,

Peter
Peter. I don't like to hear of the sparking (arcing). As posted previously it will erode the material at the points. I think I would try the effect first of fitting a capacitor across those points to subdue it. I can't think it would alter the action but you never can tell! Start with a 0.1uF or perhaps a 0.25uF. It needs to have an appropriate working voltage rating but I doubt any would be too low. Here's the real deal but a bit expensive:
https://uk.farnell.com/cde-mallory/254m06qd150/arc-suppression-snubber-network/dp/2409734
Here is the data sheet for it:-
www.farnell.com/datasheets/1725110.pdf?_ga=2.228044125.1300235979.1535183583-2036890564.1535183583
Or on Amazon:- https://www.amazon.co.uk/Bosch-Supp...d=1535183888&sr=8-1&keywords=0.25uf+capacitor

Gosh these do seem expensive! Am I really that old - that far adrift? These used to cost pennies!
Here you are this is a better price. Just as good It's just an ordinary run of the mill capacitor:-
0.22uf capacitor | eBay (0.22uF is a newer "preferred" value)
Regards, BerryG.
 

sophiebear0_0

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Thanks Berry

So that has brought us back nicely to the original topic of spark suppression. Thanks for taking the time to pot the links.

The article I cited in my earlier post by Rod Elliot seems to suggest that a resistor is a preferred option. Certainly that was the approach used by ATO. Interestingly I do own a Japy electrique clock which has a very similar movement to the Reform (albeit a little more bulky). This does have a parallel resistor as part of the original design. I also seem to recollect that the Kienzle 606 has a resistor as part of the base design (though I may be wrong !!). Both these movements work of 1.5 volts.

One thing I have found with the Reform movement is that the knurled nut used for setting the contacts gap is prone to moving with time. Perhaps this is not too surprising because the kick wind action is quite vigorous as the contacts close. I have found that a dab of locktite works well to prevent the nut moving.

My experience is that the Reform-type movements, once set up, do work pretty well and don't require much ongoing attention. They are however pretty noisy as the solenoid activates every 7-8 minutes.

Thanks again for sharing your knowledge.

Best regards,

Peter
 
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Berry Greene

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Oh it's a pleasure to exchange Peter.

I'm a hobbyist clock collector. I've had a largely unfulfilled interest since my childhood. I did electronics for a living and I am supposed to know about it! The use of a resistor to quench the spark is odd as no matter how you connect it, and how small its value, it represents wasted power. A battery system working on 1.5 precious volts, can't afford to waste anything. IMO of course!

The frequency of the remontoire re-charge seems to vary wildly. You mention 7-8 minutes, and John Harrison's was every 30secs. The one I have here "whirrs" every …..? ….? Well I am still trying to assess that. It's not altogether consistent, varying between 45 & 80 mins in the table I have so far assembled.

I love this unexpected variation. It's so nice to have the electric connection accepted by horology. There is understandable resentment towards the quartz because it has buried much of what was once a proud & clever industry.

Nevertheless, I particularly appreciate the step in accuracy afforded to the mechanical escapements of yesteryear (pendulum & balance wheel) by electrification. The even impulse a remontoire gives - the consistency of a magnetic impulse to a pendulum or balance lets me see them as they could be. Fine measurers of passing time.

My motorised remontoire isn't loud but it catches you unaware. A bit like a bee or wasp it startles rather than frightens. The burst is surely no longer than 1.5 secs??

I will be looking into other electrified clocks now. Thanks so much for the encouragement.
Regards, BerryG
 

Berry Greene

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I have been reading through the various links and previous posts on the electric remontoire and general "electrification" rather than electronic devices. That is something I should have done before jumping in here with my ideas of spark suppression. However, these were not wrong - merely incomplete.

This link Spark Quench in particular, pretty nearly covers it all. I have no issues with a word of what is said except the drawings (reproduced below). The capacitor solution is, for my money, shown incorrectly. It probably crept in from when modifying the same drawing because this chap obviously knows what he is talking about.

spark-f5.gif

I would want the capacitor (0.1 - 0.25uF) to be placed across the switch contacts. This provides an ac by-pass {LLH dwng}. I like the Zener diode solution too - it is even better, - but again I'd put them across the contacts. to limit excesses. Surely it is the energy that appears there that we need to snub out and not that within the solenoid.

A capacitor across the solenoid will just lower the natural resonance frequency. It might affect the ability of the energy to jump the switch gap but I doubt it. It might also reduce the energy available to do the "work". Anything across the coil will absorb its energy and its ability to do its job.

Here is purpose made device:- 1N6276 datasheet & applicatoin notes - Datasheet Archive It is rated at 16V. That would subdue the arc.
1N6276 Datasheet PDF - Datasheet4U.com

This brings us to the best electronic solution which is a transistor switch. Once under consideration it is but a short step to the complete replacement of the contacts with a magnet and Hall effect transistor. However I completely understand those who would say they need to keep more of the originality. You just want to extend the life of those contacts!

The ideal transistor switch would have NO physical contacts. A magnetic operation would obviate that. However there will be those who might wish to retain the original switch contacts and just take advantage of the much lower current a transistor needs to pass through the contacts thus to extend their life. Unfortunately, even this is not necessarily so straightforward! Some materials such as gold don’t tarnish and will work well with low currents. Other materials however, DO tarnish and rely on a small arc to clean or “Whet” them. Those with a mechanical "wipe" action are better in this respect but inevitably, they will in time wear away. It seems to me that all the clock circuits make a high demand on the switches. My own remontoire (which brought me here) is now determined to operate every 40 mins. It might occasionally skip a wind and go to 80 mins but never longer. Working on the former means the switch operates over 13000 times per year. That sounds more than enough and yet it pales into insignificance with some electric clock demands, does it not? More information please.

I'm here to learn & to discuss.

I cannot now leave this subject without a rather incomplete mention of the switch contact materials. What various metals do under arcing and wear & tear is somewhat interesting. It would be even more so if this writer had more knowledge than he currently does of the various metals used. I recall from my electronic relay days that there were different contact metals for differing applications. Alas not what they were! Iridium ? Gold? Platignum ? Those sorts of metals I think

Let us just consider what we would like:- Highly conductive, hard wearing, non tarnishing, arc resistant, non-oxidising, good dielectric strength. Did I not say affordable? :<))

There are "schemes" to help with some of these problems. Physical self wiping, snap hysteresis action, specially developed alloys.

Best regards, BerryG
 

flynwill

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That is indeed a well-written article, and I agree that the back-to-back zeners is a good approach, I like the fact that it is a polarity in-sensitive, meaning that someone with less electrical knowledge is less likely to get wrong. One option the poster doesn't explore is a diode plus a resistor in series, which I think would work well also, but does require that the resistor be chosen to be about 5-10x the coil voltage. This works the same as the resistor alone but eliminates the power loss to the resistor while the coil is activated.
 
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flynnr2

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A long overdue update to the original post & some follow on questions I could use some advice on.

Update
- Found a source for tiny brass rivets (supplier to scratch build modelers)
- Soldered one in as a proof on concept & it worked after a fashion
- Clear in needed a proper cleaning & the circuit mechanism needed alignment so I put it away for a rainy day
- That day turned out to be this past weekend, so it is now cleaned, reassembled, aligned, & appears to be running consistently

Context
Using my auto-sensing multimeter I find
- 0.2 ohm across the meter itself
- 0.6 ohm across coil + meter, so 0.4 ohm for coil
- 0.9 ohm across entire circuit + meter, so 0.7 ohm for entire circuit
- Power is a 3.3V no 6 battery (actually a rechargeable substitute from Ken's Clock Clinic)
- Self-wind mechanism fires every 8 minutes or so

Questions
1) I was going to apply Deoxit Gold to the 2 brass contacts that complete the circuit and leave it at that. Does that sound reasonable or would anyone suggest additional measures to preserve their longevity?
2) I was going to install 2 1W 10V Zeners back-to-back as spark suppression (which I can do with no modification to the mechanism, so easy to restore to original configuration). Will that be appropriate given the context on the electronics above?

Cheers in advance,

Rick
 

Berry Greene

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Gold offers low resistance contacts and is good for switching low currents such as RF. However, I think your currents and BEMFs will not suit gold which is a soft metal and may well migrate or burn away quite quickly.
Any spark suppression is a good idea. However when the spark is entirely quenched there is no whetting and the oxide build up might make the contacts go HR (High resistance). Hence the use of "wipers" or knives in switches made for this purpose. I think iridium is the contact of choice but you would need to get your wallet out.....!
Maybe you should continue as you are and blaze a trail. At some point you will have more answers that perhaps we or I have. Zeners might reduce the extent of the spark keeping enough to whet but not to burn. That would be a good place to be.
I have seen electric remontoire clocks that keep quite amazingly good time. It leaves me with no doubt that John Harrison was quite correct. The remontoire is the only way to go for mechanical escapement accuracy. That was 300 years ago....! His was mechanical but... same gain.
Good luck and best regards, BerryG
 

Jmeechie

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Hi,
On the Rempe switch it is a wipe designed contact. On all of mine the contact was missing from the spring. I would recommend Platinum for both contact point surfaces. I suspect the reason the piece is missing from the spring side is due to the pressure applied during the wiping action and such a tiny hole to rivet/solder to the spring. Another big issue is adjusting the switch and fixing excessive wear on the plate that holds open the contacts and then wipes the back along with the arm flexing the spring!
I’ve been trying several different forms of spark quench on mine and the issue so far on the diode is it tends to hold the solenoids closed! I’ve been running 1mf 400v capacitors across the solenoids and have eliminated the spark.
I’ll attached a video of switch closing on mine.
Cheers,
James
 
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flynnr2

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We may be the only two (certainly two of few) Rempe owners left in the world!

Thanks for the video, very familiar at this point. On thought I had was not letting the plate wipe the rivet contact (by moving the contacts a bit inboard - agree that is probably why my rivet was lost, lots of force applied) if I could keep the contacts clear.

Have you tried the back-to-back Zeners as a solution (and it keeps thing closed) or just straight up diode?
 

Jmeechie

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Your probably correct! Rempe’s either work or they don’t! And are frustrating little pains!
Well, with lots of playing with this switch, it has numerous flaws! 1. The fiberboard the contacts are attached to warps and cracks (breaks like my one in the video!) distorting the alignment and contact of the plate! 2. The little sloped section on the solenoid plate wears on the back causing the contacts to not snap closed! Rather they slowly come in contact! 3. Previous poor repairs! Like bending the little brass arm all out of shape! 4. Little to no knowledge of design intention! I tried lessening the pressure and it either doesn’t complete the opening completely or hits the spring on the gap opening.
As far as the Zener diode setup, I tried and still got a small spark, facing and opposed. I’ve seen this setup recommended both ways. Here’s the deal on a Zener, instead of open one direction preventing current flow, it breaks down and allows voltage over a set threshold (10 volts) so with 2 facing each other, it really doesn’t dump, shunt the voltage completely! Let me know what you get.
I’ve owned/collected and repaired electric self winding clocks and something I’ve come to realize is trial and error! Diodes (fast acting) sometimes work, resistors, capacitors also sometimes work! Some manufacturers used resistors like American self winding, Gregory and SWCC. National used a capacitor.
Wear, material used and quality (let alone poor design) on the contacts personally along with magnetism in the coils cause the majority of problems.
I’m getting ready to replace the contacts with platinum on mine ($17). I really hate to tell you, but brass will burn, tarnish along with silver! I’ve tried the contact cleaner/protector and had very little luck!
Btw, 8 minutes a rewind is kinda short? Mine is averaging 12 minutes a rewind. Try 2 pair of “D” cells for 3.3 to 3.5 volts with more amperage! These clocks were looking for 2 huge cells full of voltage capacity and amperage! I just saw your using 1 of Ken’s rechargeable and I really don’t think your getting the push these coils need!
A discussion I keep meaning to post is amperage along with voltage is a factor to consider with these clocks. I have done my best to research the old no. 6 cells and they were (?) somewhere around 26 flash amps vs 2 “D” cells parallel are 11-14 flash amps. Food for thought.
Here’s Henry Rempe’s patent US737019.pdf which hopefully helps explain the wiping switch.
Apologies for the long response
James
 
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Berry Greene

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Fascinating! There I was butting in hoping to help when all the while you're streets ahead of most things I say!
No matter I am enjoying this because the issue comes up in one form or another over and over again. The use of DC (Battery) into an inductor or (coil) via a switch (commutator) has ever been difficult because of arcing. Take the dynamo or DC motor with brushes and split segment commutator. Often carbon or copper brushes on a copper segment. Or the old car dizzi points.

There are a few allied things to say here without being specific to your own problems which could help if you can find a way to stitch them together for your particular needs.
A DC switch will have a sharp toggle and knives for the contacts. The arc is actually ionisation of the air..... Ah! The material is vaporised and transferred in one direction with DC.
You want as little time in proximity as possible (hence the toggle), or you need to exclude the air. In early times they used a mercury switch within a glass vial. The vapour was collected and condensed back into the little puddle of mercury. So first suggestion is can you, without compromising the originality too much, use a mercury switch?
OR chaps...... (I'm English remember) could you make use of a little magnetic reed switch? These are encased in a glass vial which is filled with an inert gas which stops the arc. They are operated by a magnet.
Now I don't know your specific clock and it looks as if not many ever will if you have the only examples left!
That said could you modify to place a magnet on the calling armature? Here is one example. Be warned I have not and indeed cannot research the current ability needed for your application. I am just floating a few ideas here.
FIG_1.png
Can I post a link here? Maybe not. I'll post some extracts., A search will find all the relevant info.


EXTRACT (Reed Switch Developments Corp)
In the fact, magnetic-based reed switches, either as bare reeds, reed switch sensors, or as reed switch/actuator sets, presents a number of unique advantages within finished product designs, including:
  • Simple and reliable reed switch sensing and actuation capabilities
  • Low-profile designs offer ease of integration
  • Requires zero power for operation
  • Durability and performance over extended service life
  • Low weight prevents mass loading of sensitive electronics
  • Low price point per unit
  • High performance with low overall cost of ownership
  • Relative ease of customization

Look also at Fierce Electronics. The have quite a lot on their website.

I hope it helps. Keep going. Fascinating!
Best rgds BerryG
 

flynnr2

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Cheers all for the input - will revert with some answers over the weekend (good early morning project before the household wakes up + I have bruised ribs, so can’t put the engine in my Sunbeam Tiger back together yet). Will try to include some decent photos of the mechanism if folks are interested (or for posterity’s sake).

Jmeechie Totally agree about the quality of the design and materials leading to “challenged” repairs over the years, difficult to rectify cleanly. Was thinking that some 3D printing might be able to produce a suitable substitute for the fibreboard (though then I’d have to wrestle with the rivets or whatever it is that secures it)? Have read that patent a few times over the years since this clock darkened my door ...

Berry Greene I am more of your maths & engineering type; basic household & automotive (+ a bit of computer networking) is about my limit, so I need to rely on the kindness of others for this more advanced stuff. FWIW, I spent 20 years in Blighty (or South London to be more specific, though one might argue that is a different planet) so you can consider me bilingual (I also do small sideline in proper irony from time to time). Perhaps I should update my flags to better reflect that.
 

Wayne A

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Btw, 8 minutes a rewind is kinda short? Mine is averaging 12 minutes a rewind. Try 2 pair of “D” cells for 3.3 to 3.5 volts with more amperage! These clocks were looking for 2 huge cells full of voltage capacity and amperage! I just saw your using 1 of Ken’s rechargeable and I really don’t think your getting the push these coils need!
A discussion I keep meaning to post is amperage along with voltage is a factor to consider with these clocks. I have done my best to research the old no. 6 cells and they were (?) somewhere around 26 flash amps vs 2 “D” cells parallel are 11-14 flash amps. Food for thought.
Rechargeable battery's performance varies considerably with cell type and brand. For 3.3v you can use a A123 LiFeP04 type cell and they come in a few sizes and are capable of large surge discharge currents of 120A. They don't self discharge and are not harmed left fully charged but the down side is there a bit heavy and performance drops in cold temps. I use these A123 cells in another hobby with flying model's.
Here is a link to an example cell. A123 LiFePO4 26650 Rechargeable Cell: 3.3V 2500 mAh, 50A Rate, 8.25Wh, ANR26650M1B, ANR26650M1-B
 

Berry Greene

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Cheers all for the input - will revert with some answers over the weekend (good early morning project before the household wakes up + I have bruised ribs, so can’t put the engine in my Sunbeam Tiger back together yet). Will try to include some decent photos of the mechanism if folks are interested (or for posterity’s sake).

Jmeechie Totally agree about the quality of the design and materials leading to “challenged” repairs over the years, difficult to rectify cleanly. Was thinking that some 3D printing might be able to produce a suitable substitute for the fibreboard (though then I’d have to wrestle with the rivets or whatever it is that secures it)? Have read that patent a few times over the years since this clock darkened my door ...

Berry Greene I am more of your maths & engineering type; basic household & automotive (+ a bit of computer networking) is about my limit, so I need to rely on the kindness of others for this more advanced stuff. FWIW, I spent 20 years in Blighty (or South London to be more specific, though one might argue that is a different planet) so you can consider me bilingual (I also do small sideline in proper irony from time to time). Perhaps I should update my flags to better reflect that.
Blimey matee you're more London than meself! I'm from West London and would not go south without me army. Crossing that River Thames was fraught with danger! I moved down to Sussex and escaped to become a member of the farming community and gentlefolk. Moo!

I just though I might be able to shine a little light or open your mind to possible solutions not yet considered. I know that you might want to preserve the authenticity and that's fine. However, such contacts were ever a pain which is why such workarounds as I described came into being.
Strictly speaking a solid state transistor switch is best of all. I have number of pre quartz electric balance clock movements here. Little magnets on the balance are detected by a sense coil and a pulse is then applied to keep the balance running. The necessary switch is a transitor. It keeps very good time - not quite up to a quartz but close. C cell lasts well over a year. Kienzle, Smiths, Metamec, Kundo examples come immediately to mind. Another version again by Kienzle employs a mechanical remontoire that is re-wound every couple of minutes by a solenoid that throws/pushes it a short distance into a rewind against a ratchet or click. The light watch spring drives a standard balance and the timekeeping is very good. My example has a D cell. Someone gave me a box of bits and I have managed to make just one up that works. The solenoids are the missing part. Perhaps they burn out? The contacts are probably platinum plated ?? (The oxide is black - like soot, No conductive). So I have an interest in making something better.
Yet another similar device uses a motor to re-wind the remontoire. It is a spasmodic performer. Not such a classy balance EW & lever. Not sure why but I suspect the contacts are to blame on this one.
These are not old or precious items. I don't embrace precious as I want to play with them! I treat them well mind.
Good luck and keep us posted.
ATB BerryG
 

Jmeechie

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Jmeechie Totally agree about the quality of the design and materials leading to “challenged” repairs over the years, difficult to rectify cleanly. Was thinking that some 3D printing might be able to produce a suitable substitute for the fibreboard (though then I’d have to wrestle with the rivets or whatever it is that secures it)? Have read that patent a few times over the years since this clock darkened my door ...

I like your idea on the 3D printing of the insulation block! The rivets to mount wouldn’t be a problem to replicate or using micro screws and nuts! My biggest concern was recreating the 2 square mount holes for the contacts as position and alignment Is fairly critical. I’ve measure the spring along with the notched hole dimensions in the event I need to replace one one day!

I'm also considering making a nickel strip (this afternoon) for the spring vs silver (a lot of darkening after several months of running) I’ve been testing and before fitting the platinum.

Berry,
The reason for not using gold is it’s too soft and would have a high wear rate! The majority of these contacts are of a wiping design. A mercury switch was used by National Self Winding clock (Unfortunately defective when delivered) let alone the concerns mercury carries. Another factor needing consideration is the switch needs to maintain contact for more than a instant to allow full winding, creating a whole redesign of the switches design.

Oh, and as far as dialect, I’m fae Dundee (spending several years in Clydebank!) transplanted to the US, so understanding any Queens english isnae a problem!
 

flynnr2

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Used to travel past Millwall's Den twice a day - mounted police on the elevated train platform was de rigueur on match days for a fair while. I also unwittingly attended a Roma match at Stadio Olympico once and ended up sitting in the Curva Nord. Lest anyone wonder, I am actually not much of a football (read: soccer) fan per se, but live sport is usually quite entertaining ... quirks of my life.

Did squeeze in a bit of time with the Rempe over lunch, so a few updates on the power side of things (will restate all for completeness)
- 0.4 ohm across the solenoid alone (0.6 ohm - 0.2 ohm for the meter)
- 0.7 ohm across the entire circuit (0.9 ohm - 0.2 ohm for the meter)
- Original power source was 2 X no. 6 batteries
- Current power source is
- 1 X 3.3V Lithium Iron Phosphate (LiFePO4) rechargeable battery
- ~1.25 max amps in the circuit
(measured in series between negative pole & solenoid over a few hours of ticking)
- Confirmed with battery supplier
- Current limited device around 1.5 amps
- Max could hit 3 - 4 amps because of a time delay mechanism in battery circuitry
- ~0.18 ohm output resistance which is expected to be stable across life of battery (vs more traditional options)
Mechanism is working a treat by & large, but you can definitely smell the odor from the arcing once it has been running for a while.

Will aim to try the Zeners this weekend as well as get some reasonable photos and report back.

Cheers again to all the input, very helpful.
 
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Jmeechie

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Sounds to be good power supply! I just measured my coils and I have 2.2 ohm so you’re on the low side I’m thinking? Measured my National Self Winding (2 different movements) and got 2.4 on one calling for a capacitor and 4.4 for a late production that deleted the capacitor requirement. Also a Grav-Elec and got 4.1 and a Gregory (that I know certain has a built in factory resistor) and got 2.2. I have 0.5 on the meter.
Curious to see how the Zener’s work for you.
BTW if the nickel works for the contact I can send you a length to make a contact.
Oh, and I was inspired to dig through my pending (some day) projects and found I have another complete movement (minus solenoids and it has complete contacts! They’re silver colored but not sure of what?

8A4530A4-BEF3-4221-B888-637A5A6F90A4.jpeg
 

flynnr2

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Jmeechie I do wonder about the ohm readings but I changed the battery in my digital multimeter & measured the resistance of some known quantities and it all seems fine. Perhaps someone more knowledgeable than I could take a guess at the disparity in readings but at the moment, the coils are doing their job so I’m not wondering too much.
 

flynnr2

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Weekend Update
- back-to-back Zeners (1W 10V) across the contact posts appear to be suppressing the spark
(no visual evidence in a dark basement, no odor, satisfyingly crisp click when the circuit closes - not my finest soldering job to be fair, be kind)
- running fine since 0800, needs a bit of fine tuning on the beat & time keeping
- will leave it like this for the nonce
- exceedingly generous fellow forum member who I will refrain from embarrassing publicly is posting me some replacement contacts he made for a similar Rempe, so there may be further fettling in the future!
(I also have some suitable cloth covered wire if I feel so motivated, though the current stuff seems fine)
- might explore 3D printing a replacement for the fiberboard cross member which holds all the electric connection posts

Thanks to all who have pitched in, the advice and thoughts have been very helpful.

As promised, photos of the mechanism in a slightly disconnected state follow ...

rempe.rear.jpg rempe.left.jpg rempe.front.jpg remp.right.jpg remp.top.jpg remp.top2.jpg remp.messy.zeners.jpg
 
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Berry Greene

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Thanks for the pics. Great help. I think you're right on to this from what you say. It sounds very good. Soldering is a knack that's easy to lose. I did some myself this week. Its a slick art and this modern silver solder is awful! I sometimes use some Bakers Fluid on older parts - even on wire. Its Zinc-Chloride solution and it works. I keep some lead based solder too as it flows much better. Sshh! The difference is amazing.
Good luck and keep the faith. I think you are going to win over this.
Best rgds BerryG
 

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