Eureka Eureka Clock

Caton

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Oct 11, 2019
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I aquired this Eureka Clock which has just been serviced prior to me aquring it. It has a governor attached which came from Carlton Clocks. The clock was gaining several minutes a day, so I regulated it with the star wheel, and came to the end of the adjustment. The clock was still gaining, but about a minute every couple of days. I checked the voltage with a voltmeter from the contacts of the governor, and it was showing 2.84 volts. Is that the best place to check the voltage? Using the pot trimming tool I reduced the voltage to 2.6volts which slowed the clock down and I turned the start wheel to gain by a few turns. It's now keeping virtually perfect time. I know that it should run on 1.5volts, and my question is, will 2.6 volts damage the contacts? Or should I reduce the voltage more?
 

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praezis

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At least I would add a spark suppressing resistor (220 ... 330 Ohms) parallel to the coil. This will reduce the back EMF voltage to harmless 20 V.

In my clock it looks like this:
Eureka_resistor.jpg

Frank
 
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Caton

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Thanks for that Frank. Where would I get one from and how would iI wire it in?
Phil
 

wisty

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Phil,
Can I make a couple of comments.
Looking at the video of your clock, the arc of the swing looks a bit low. They should run somewhere around 300 degrees of swing. A short swing will tend to make the clock gain, a longer arc slows it down.
Another way you can regulate a Eureka is to swap the big screws on the "balance" wheel around. They are usually of two or sometimes three different weights. It's not actually a balance wheel in the watch sense and on my tall Eureka movement I found I could vary the rate by plus or minus two and a half hours per day simply by swapping pairs of screws. It takes a bit of experimenting. Increasing the weight at the top (top is the high side when the pin hits the flag) will slow it down, heavy at the bottom will speed it up. Poising the wheel is unnecessary and probably counterproductive.
You should be able to het a better swing at a lower voltage if you can tweak the positions of the screws.
There is more detail in this thread Eureka - Help with Eureka clock | NAWCC Forums my contributions are #18 and #24.
 
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praezis

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Where would I get one from and how would iI wire it in?
Phil,
I used a SMD resistor on a small board, but you can use any small (1/8 ... 1/4W) resistor. It is connected between the post, where one wire is soldered to, and the brass disc (see pic).

Frank
 
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Caton

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Phil,
Can I make a couple of comments.
Looking at the video of your clock, the arc of the swing looks a bit low. They should run somewhere around 300 degrees of swing. A short swing will tend to make the clock gain, a longer arc slows it down.
Another way you can regulate a Eureka is to swap the big screws on the "balance" wheel around. They are usually of two or sometimes three different weights. It's not actually a balance wheel in the watch sense and on my tall Eureka movement I found I could vary the rate by plus or minus two and a half hours per day simply by swapping pairs of screws. It takes a bit of experimenting. Increasing the weight at the top (top is the high side when the pin hits the flag) will slow it down, heavy at the bottom will speed it up. Poising the wheel is unnecessary and probably counterproductive.
You should be able to het a better swing at a lower voltage if you can tweak the positions of the screws.
There is more detail in this thread Eureka - Help with Eureka clock | NAWCC Forums my contributions are #18 and #24.
Thanks for that. I will try adjusting the screws
Phil
 

Caton

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Oct 11, 2019
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Phil,
I used a SMD resistor on a small board, but you can use any small (1/8 ... 1/4W) resistor. It is connected between the post, where one wire is soldered to, and the brass disc (see pic).

Frank
Thanks Frank
 

Caton

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Oct 11, 2019
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Phil,
Can I make a couple of comments.
Looking at the video of your clock, the arc of the swing looks a bit low. They should run somewhere around 300 degrees of swing. A short swing will tend to make the clock gain, a longer arc slows it down.
Another way you can regulate a Eureka is to swap the big screws on the "balance" wheel around. They are usually of two or sometimes three different weights. It's not actually a balance wheel in the watch sense and on my tall Eureka movement I found I could vary the rate by plus or minus two and a half hours per day simply by swapping pairs of screws. It takes a bit of experimenting. Increasing the weight at the top (top is the high side when the pin hits the flag) will slow it down, heavy at the bottom will speed it up. Poising the wheel is unnecessary and probably counterproductive.
You should be able to het a better swing at a lower voltage if you can tweak the positions of the screws.
There is more detail in this thread Eureka - Help with Eureka clock | NAWCC Forums my contributions are #18 and #24.
There are only 2 small screws on the balance wheel, but I have moved them as you suggested. In truth I only had to move them one space but the clock is now gaining about 15 minutes a day after the star wheel has been adjusted to the end of slow. Before I adjust the voltage, does screwing out the big screws at the bottom of the swing speed it up more? They are all screwed in at the moment. Thanks for your advice.
 

wisty

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Dec 24, 2014
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Phil, I suggested swapping the BIG screws around rather than the little ones. If the rate moved from "several minutes/day" to "15 minutes/day" , then you seem to have moved the weight in the wrong direction. I would start by putting the small weights back where they came from.
My experience is that to slow the clock down you need to move weight closer to the TOP of the balance wheel. Top is the top of the wheel when at the point of impulse - the pin just hitting the flag. Moving weight closer to the bottom speeds the clock up.
If you remove the BIG weights from the wheel (ONE AT A TIME AND PUT THEM STRAIGHT BACK ), weigh them and note their position before replacing them in the wheel you should find that they are different weights. Probably two different weights, but possibly three. I would also use some sort of simple spacer so that you screw each weight in to exactly the same height above the wheel - I used a 1.5mm thick piece of plastic. (I found that screwing all the screws in and out one turn makes changes of the order of 10-20 seconds/day.).
Once you know what weight is where, select a pair where the heavy one is close to the bottom and the light one is closer to the top.
Swap them over - effectively moving weight towards the top of the wheel. Then test the rate.
If that gets you close, then well and good. If its still fast do the same for another heavy-light pair. If you have overshot and the clock is now slow, put the original pair back where they came from and pick a pair closer together so that you move less weight.
I would do this with the adjuster set about mid way, and leave it there for the tests, once you get close you can then tweak the adjuster.
This whole process is a lot easier and quicker if you have some form of measuring device (e.g. a Microset) that can measure the rate fairly quickly. If not the process will be fairly slow and you will need LOTS of notes.
If you look at the PDF I linked to in post #4, you can see the effects I was getting - be aware the image of the wheel is viewed from the back because you will probably be working from that side.
 
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Caton

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Phil, I suggested swapping the BIG screws around rather than the little ones. If the rate moved from "several minutes/day" to "15 minutes/day" , then you seem to have moved the weight in the wrong direction. I would start by putting the small weights back where they came from.
My experience is that to slow the clock down you need to move weight closer to the TOP of the balance wheel. Top is the top of the wheel when at the point of impulse - the pin just hitting the flag. Moving weight closer to the bottom speeds the clock up.
If you remove the BIG weights from the wheel (ONE AT A TIME AND PUT THEM STRAIGHT BACK ), weigh them and note their position before replacing them in the wheel you should find that they are different weights. Probably two different weights, but possibly three. I would also use some sort of simple spacer so that you screw each weight in to exactly the same height above the wheel - I used a 1.5mm thick piece of plastic. (I found that screwing all the screws in and out one turn makes changes of the order of 10-20 seconds/day.).
Once you know what weight is where, select a pair where the heavy one is close to the bottom and the light one is closer to the top.
Swap them over - effectively moving weight towards the top of the wheel. Then test the rate.
If that gets you close, then well and good. If its still fast do the same for another heavy-light pair. If you have overshot and the clock is now slow, put the original pair back where they came from and pick a pair closer together so that you move less weight.
I would do this with the adjuster set about mid way, and leave it there for the tests, once you get close you can then tweak the adjuster.
This whole process is a lot easier and quicker if you have some form of measuring device (e.g. a Microset) that can measure the rate fairly quickly. If not the process will be fairly slow and you will need LOTS of notes.
If you look at the PDF I linked to in post #4, you can see the effects I was getting - be aware the image of the wheel is viewed from the back because you will probably be working from that side.
Done as you suggest and the clock is now keeping pretty reasonable time. The voiltage is now 2.1v, but the swing is now shallower than before. In your 1st reply you said that the arc should be about 300 degrees. I have taken another video. Not sure whether to leave well alone or increase the voltage back up to 2.8v and then play around with the weights to reduce the time gain. It was gaining about 15 minutes a day at 2.8v, but not sure whether 2.8v will damage the contacts. Thanks for your previous comments.
Phil
 

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wisty

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Dec 24, 2014
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I think there still something wrong. It looks like the clock is lacking power. It shouldn't take 2.8v to get a decent swing. Attached is a short video of my tall movement - its running on about 2v( but under the control of one of Frank Roesky's controllers which cuts the power to control the swing so probably closer to 1.7v).
The thing I would look at next is the gap between the armature in the wheel, and the plate at the bottom to which it is attracted when the current flows. The gap should be very small. It should be no more than the thickness of a cigarette paper .001" or .025mm. If its much greater the clock does not get the "kick" it needs To correct the problem, you need to insert shims (card or paper will do) under the bottom plate to get the gap as small as possible without the armature catching. BE CAREFUL the gap when the current flows reduces slightly as the armature is attracted down. If you set it too close without power, then it will catch when you apply power - bit of trial and error is called for.
 

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