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Eureka clock balance wheel

Ashford

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Dec 4, 2020
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I hope this information is of use to people struggling to set up these clocks, having struggled to get mine running near normal. The balance wheel was the issue, having spent hours on every other aspect. Put simply if the balance wheel is not BALANCED it will never run correctly. Do not assume the weights are in the correct position just because the clock looks tidy, as I did.
The balance wheel should be balanced like a car wheel after having a new tyre fitted . It should stay poised at whatever angle it is positioned. The wheel should have no bias or tendancy to settle in one position when turned. The simple way to achieve this is to number all the weights as they are removed and weigh each one and note it down on paper. Then the job of achieving correct balance by replacing them in a logical sequence can begin. This may take some time but well worth it. With a coil resitance of near 20 ohms give or take an 1-2 ohms and bearings in good order, 360 rotation will be acheived with 1.5 volts.
I could not find this simple information anywhere, in fact I read some contradicting information saying it was of little importance because the spring would rectify any inbalance... hogwash!!
 

James McDermaid

Registered User
Apr 29, 2011
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My Eureka keeps good time, I have not had the balance apart or messed with it. I get about 365 degrees of swing on about 2 volts.

It was of course the big balance wheel that attracted me to the clock in the first place.

The dissenters all claim the balance is nothing more than a pendulum but I disagree If you read through the Peter Smith restoration of which there were a large amount on the web, he talks about how some of the poising weight's .are undercut and appear to be of different weight.

They say no temperature compensation but the balance is bi-metal, Brass and Steel in the proper order.

When I got my clock it gained about 30 minutes a day. The tail of the balance spring was too long out of the clip on the frame. I picked a spot and moved it=. I had to loosen that teeny screw in the spring collet and rephrase the balance. If I stop it the contacts are resting on closed and it will re-start. If I stop it I get it in a direction it won't start.

In this changing weather it sometimes gets of a minute in a week and I rotate the adjusting wheel a line or two. It ran from something like January to October and stayed perfect.

I have the regulated battery but everything else is original.

Jim
 

Ashford

Registered User
Dec 4, 2020
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Hi Jim, glad to hear your clock keeps good time. My clock was gaining about ten minutes an hour !. I adjusted the spring checked all the usual culprits for issues and found none. It was only when I investigated the wheel when I noted it was not balanced correctly, but it was behaving like a pendulum and weighted with the bias showing the coil in the near vertical position at rest, which looked O K. I have some concerns that your clock is running with 2 volts as 1.5 volts is the aim. I wonder if you diconnected the spring and drive chain so the wheel was resting on the bearings only and free to move, whether it would be in perfect balance.
Roger
 

James McDermaid

Registered User
Apr 29, 2011
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Being lazy I have not tried the wheel for poise but I should just to see why it keeps decent time.

I am aware I should be running 1.5 volts. I have the regulated #6 look-alike that Carlton Clocks sells adjusted to 2 volts. I don't recall if I tried a lower voltage.

I would think the balance spring should be removed completely for poising, and the drive chain released from contact.

I figure that if I start tweaking things could go downhill.

When I got the clock the contact pin was loose in its mount and the spring was turned through the clamp, making it short and causing the clock to gain. It gained 30 minutes in 24 hours.

I fixed those things got it running and went on to other clocks while evaluating my work. I don't know the history of my clock, It was sold at auction in the UK and came to the US with a quantity of clocks by a dealer I know.

The first Eureka I was smitten with was the Cromwellian model and it was a little over my budget at the time so I was shown the present clock and bought it. I went back to see if I could own the Cromwellian but it went away fast. This glass model is better as you can see inside.

In a dark room I see a tiny blue spark at the contact point, As they are made of silver there is some special ability of silver to endure the arc. I want to see it run in its original design so I have resisted adding a diode, or an MOV, or pulse circuit. I guess people have had good results with diodes, keep in mind the coil needs to loose its charge fast. Induction coils used in automobiles for ignition had a capacitor across the contact points. The capacitor tunes the coil so it produces a better spark.

I bought a spare contact set and spare glass discs I am saving for the day.

Jim
 
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Ashford

Registered User
Dec 4, 2020
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I would guess that your wheel is in good balance. When I increased the voltage on my clock prior to balancing the wheel all that happened was the wheel went further in the arc and also faster. the clock still ran too fast as before on 1.5 volts. It may be the case that your clock will run fine on 1.5 volts.
You are right that all the weights had diferent values when weighed. It is important to replace them in original order if the clock runs well, in my case the wheel was well out of balance so it made no sense putting them back in the same order. I still find it strange there is little detail on the importance of the wheel being inspected for balance and the importance of this.
I spoke with Carllton Clocks and they said if the wheel is not balanced the time can be way out, so again why is this given little mention on restoration details.
Roger
 

James McDermaid

Registered User
Apr 29, 2011
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I thought I had read in one of Peter Smiths restorations where he talked about balancing the wheel.

There seems to be not history from the original maker.

Jim
 

kronouer

Registered User
Apr 23, 2015
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Greetings Roger and Jim,

Am struggeling with an Eureka Clock.

When I got the clock, all the timing screws were lose in a plastic bag (at least they were all there!)

Got it to run on time (within 1min/day), but very low swing on 1.9 volts.

A lot of guess work and not too much science.

Swing not more than 180 degrees.

Will try Roger's balancing.

To make sure I understand fully:

I unscrew the collet of the hairspring on the balance wheel arbor.
The balance wheel is free to spin, except for when touching the contact flag.
I place the balance wheel weights to get perfect balance in any position.
Now, fasten the collet of the hairspring on the rotor arbor, rotor at rest, at about 30 degrees from the contact flag.

Many thanks!

Hans
 

kronouer

Registered User
Apr 23, 2015
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Hi Roger and Jim,

My previous message was incomplete due to excitement of finding some useful Eureka information.

In my summary of what to do I shoud have added the disconnection of the motion work in order to balance the rotor.

Once I have completed the poising of the rotor i still have to get the timing right.

For this I need to move the rotor weights, if I follow the Peter Cook guidelines.

How do you suggest i get the clock to run on time once completed the poising of the rotor?

Kind regards,

Hans
 

Ashford

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Dec 4, 2020
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Hi Hans
Nice to have a message from another struggling Eureka clock owner. Just to be clear, the balance wheel should be free of all attachments so it can be then balanced properly by moving the weights around. I used very accurate digital scales to weigh each weight and numbered them. The wheel when free to spin should settle in any attitude when correctly balanced and have no bias, like a perfectly balanced car wheel. The collett should be tightened so that the spring tension allows the silver contacts just start making contact, however this is not critical as it only helps to start the clock after stopping. The coil resistance should be near to 20ohms. With 1.5 volts the rotation should be near 360 degrees. If the rotation is a lot less the clock will gain time because it will take less time to complete its fuction and go faster. When the basic mechanics are correct the clock should keep time
Roger
 

kronouer

Registered User
Apr 23, 2015
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Greetings Roger,

Many thanks for your prompt reply!

Can you please clarify the last tricky part?

I do all the correct poising and the clock runs on time ?

No further adjustments needed ?
The screws were made to be screwed in/out while in place on the rotor.
This is needed for poising?
Is this the fine timing adjustment?

The hairspring length can be a adjusted by the clamp at the back of the frame.
This should affect the timing of the clock.

All this seems to contradict what is said in the Peter Cook Powerpoint presentation.
Or is Peter Cook inadvertently trying to balance wheel?
See attached link.

Sorry I am confused and do not fully understand the workings of these clocks.

Hans
 

Ashford

Registered User
Dec 4, 2020
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Hello Hans,

Sorry I did not realise you had no understanding of these clocks. I cannot go into all the aspects. My main concern was with the fact that the wheel must be balanced, without this the clock will never keep time. To answer the questions you raise I will explain. The poise screws can be srewed in or out but should not be set down tight to the wheel but should show a small gap. The effect of moving them in or out has little effect on the timing, more important to get them in the best strategic position, this will take concentration. The main spring will also effect the cĺocks timing and needs to be adjusted at the lower clamp. This can vary from clock to clock some may show 10cm plus of excess spring past the clamp and some nothing after adjustment. The star wheel gives the fine adjustment. Also make sure that the click spring on the ratchet wheel is not pushing down too hard, as this can effect timing. If the balance wheel is balanced and the voltage is correct and the rotation is less than say 300 degrees then there is a problem else where and needs investigation. I hope this helps



Roger
 
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kronouer

Registered User
Apr 23, 2015
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Thank you Roger.

My apologies for my questions, but am trying to fully understand how these clocks work.

Your observations are very clear, and as I am an amateur, it will take me, say a week, to implement the balancing of the rotor.
Will let you know how I go.

Struggling to comprehend the timing theory of the Eureka clock.

1) Take your method to its logical conclusion. At the factory they balanced the rotor. Maybe adjusted the hairspring. Clock ready to be sold.
The design is such that no further adjustment is needed. (I have Carlton Clocks replacement hairspring).

2) The Peter Cook presentation seems to contradict your advise. See the link. Could you please comment on this?
I followed the Peter Cook principles and have my clock running, although with a poor swing and average timekeeping.

Kind regards,

Hans
 

Ashford

Registered User
Dec 4, 2020
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Hello Hans

I cannot find the link you mention but I have attached a page from Alan Shenton book of the eureka clock, this is full of information which I suggest you get a copy. If you are getting reasonable time with a poor swing I would take this as a good result but defies logic. Consider a pendulum with a swing of say 160mm if it is reduced to say 100mm then the clock will gain time, because the operating cycle has been reduced and the mechanism will work faster. I stress again you must start with the key points, voltage at 1.5v ,resistance in the coil at around 20 ohms and a correctly balanced wheel. With out the basics the rest will be irelevent.

Regards Roger View attachment 634700
 

Ashford

Registered User
Dec 4, 2020
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Sorry I may be in breech of copyright so I have deleted attached page, It mentions the balance wheel rotation and oscillation rates

Roger
 

kronouer

Registered User
Apr 23, 2015
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Greeting Roger,

My main question remains, namely, once I balanced the rotor following your recommendations,
HOW DO I GET THE CLOCK TO RUN ON TIME?

The star regulator, in my case, has minimum affect on the timing of the clock.

My clock (1.5 volts) has a small swing, say 200 degrees, and looses about 10 min/day.
If I increase voltage to 1.9 volts the clock keeps very good time.
From my experience: more voltage, more swing, clock seeds up
Therefor, the analogy with a standard clock pendulum is not applicable.

As it is, my clock is running but is a poor time keeper (at the correct voltage), so I will balance the rotor, run it at 1.5 volt (and 20 Ohm on coil) and see what happens.

Can you please tell us some of your personal experiences with your clock, specially getting it to run on time?

Hans
 

Ashford

Registered User
Dec 4, 2020
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Hello Hans

I have two Eureka clocks neither of which kept good time, one did not work at all. Having spent many hours reading and using trial and error they both function well. I cannot give you a one off answer to your issues. Remember the clock was designed to run on 1.5 volts period. If it runs too fast or too slow the issues will be the same. I checked all aspects of the mechanical parts of the clocks and then the electrical side. The main issue as I said was that both the balance wheels were out of balance and this ultimately was the cause of poor operation on both clocks !!. It may also be worth you checking the clearance under the balance wheel and the armature plate. This should be a cigarette paper thickness 2-3 thousands of an inch between the bottom of the metal core of the coil and the plate during rotation. If the gap is large the magnetism will be less effective and reduce the rotation of the wheel You will need to put shims under the plate to raise it up to the correct position. I did this on both my clocks. There would have been shims there originally but they get lost over the years.
One of my clocks ran too fast when I was trying to sort it out and this was because the swing/rotation was around 260 mark and therefore took less time to complete its cycle, when making the balance wheel travel further to 310 degrees it slowed the clock down, this was not achieved by changing the voltage but by balacing the wheel and checking the moving parts.
I have a collection of Bulle electric clocks which I have restored and in most cases people had messed around with extra batteries and voltage etc. The ultimate cause of poor function was the coil , the contacts, and the magnetism. After all these are electric clocks.
Good luck with your Clock and do not make too many assumptions, check everything.

Regards Roger
 

James McDermaid

Registered User
Apr 29, 2011
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My Eureka was gaining about 20 minutes a day when I got it. The tail of the balance spring was quit a ways (long) past the clip that secures it to the frame. The screw was loose. barely snug. This made the spring short and in my mind fast.

The contact pin in the balance was also loose, I just tightened the screw and observed the position against the flag contact making sure the insulated side was such that contact is made only in one direction.

I moved the spring back where I thought it should be and then I loosened that little micro - tiny screw on the collet and set the pin so it just made contact with the flag contact- The screw was pointing down making it difficult to adjust the position of the collet.

If I stop the balance after it has turned clockwise (viewed from dial), and carefully let it come to rest it will stay stopped with the insulated side of the pin touching the flag. If I stop it when turning the other way it is in contact and immediately starts going.

I get a good 360 degree swing maybe a few degrees more. I am running on a regulated #6 dry cell repo adjusted higher than 1.5 volts, maybe 1.8 to as much as 2 volts. The "C" cells get changed about 6 months and are starting to get down to 1.3 volts by then.

My Eureka keeps better time than most of the pendulum clocks around the house. It usually is better than the ST #1 regulator.

Jim
 

Bryan Mumford

Registered User
Feb 1, 2008
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My main question remains, namely, once I balanced the rotor following your recommendations,
HOW DO I GET THE CLOCK TO RUN ON TIME?

Google "Eureka Governor" and you will see that a circuit to correct the rate of Eureka clocks may be available again in the coming weeks.
 

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