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Eureka My first Eureka

Lamela

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Jan 20, 2020
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Hello,
I have got an Eureka clock, S/N 9953. If you have in your Data Base any information about this clock, I would be very thankful. The estimated date of production will be very interesting for me.
The clock is missing its dome. I am planning to make the new one, according to any historical sources. If you have any, it will be a great help to me. Has it to be a glass only, with a rectangular bottom, or metal cage with glass windows ?
The clock is in working condition, however I think it needs some adjustments. It operates from 3V with amplitude of approx 360 deg, I am planning to change it to 1,5V. Now the balance wheel has a axial clearance over 1mm - it is normal or have I to reduce it ?
I am adding some photos, any other I can add any time.
Eureka1.jpg Eureka2.jpg
Jerzy
 
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sophiebear0_0

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Nov 5, 2012
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The cover of "Clocks -January 1997" has a picture of the Eureka glass dome. Unfortunately there is no additional information about the clock within the magazine.

Regards,

Peter

Clocks 1997.JPG
 

James McDermaid

Registered User
Apr 29, 2011
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There is substantial history on this site for the Eureka Clock.

They were manufactured about 1910 apparently at about in a period of 4 years. All made in the UK.

You have the tall style movement with two balls. There is a three ball version and a shorter version.

My Eureka has been running for about four years since I acquired it. It keeps decent time, does as good as pendulum clocks and torsion clocks I have around the house

I have a replica #6 Dry Cell battery set for about 2 volts in the base.

If you poke around on the web for Restoration of Eureka number you can find a bunch of detailed restoration stories with lots of pictures.

Love my Eureka Jim
 

Lamela

Registered User
Jan 20, 2020
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Hi, Peter
I have found in one Restoration History this rectangular - bottom glass dome. But it should be made individually, I have found such producers in Germany and England, but the costs are unacceptable. Now I use temporary standard round glass dome and I think about making a replica of metal dome, as in photo
images (1).jpg
Now I have cleaned and adjusted the mechanism, poised the balance wheel and now I am trying to make it more accurate.
Operating from 1,5 V the balance amplitude is within the range of 200 - 240 degrees and timekeeping is not satisfactory - changes from day to day.
With the cells in series - 3,0 V - amplitude is 350 degrees and the operation is more stable, however I am afraid of the fast drain of batteries and contacts erosion.
I tried to decrease the electromagnetic gap, but it is not easy, change of 0,1 mm resulted in higher amplitude, but occasionally the clock stopped - I think, that bearing is not so precise to keep so low gap.
I am open to your comments and advice.
Jerzy
 

sophiebear0_0

Registered User
Nov 5, 2012
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Hi Jerzy

Certainly the case in your post would look great.

As Jim mentioned, there is quite a lot of information on this forum as well as the book by Alan Shenton. I would also highly recommend the Horologix website that has a large number of Eureka restorations with detailed photographs and descriptions.

I only have one Eureka. I get around 300 degrees rotation at 1.6 volts. Time keeping is pretty good (around +/- 1 minute/month). A number of clocks have a diode fitted across the coil to reduce sparking and hence limit contact erosion. You can also buy regulated battery packs fro the Eureka clock. They are the same size as the original R6 flag cell, but can be regulated to give an output between 1.5 -3.0 volts. They run off 4 * C-cells and will typically give 1 year's service.

I think you could do some experimentation with a series variable resistor and your 3 volt supply to see whether a regulated power supply will solve your problem.

Others on the Forum may be better placed to provide some specific information based on experience.

Regards,

Peter
 

James McDermaid

Registered User
Apr 29, 2011
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I have been running my Eureka on a Replica #6 or Flag Cell battery that was obtained from Carlton Clocks in the UK. It is adjusted for under 2 volts ( I hate to disturb a good working clock to measure it). Four "C" cells slide inside in a clip and are in series (that makes 6 volts), there is an adjustable voltage regulator chip so you can set it where you want. The original #6 was 1.5 volts, and they were supposed to run the clock for three years. I am told by the antique radio collectors that a "D" cell has as much capacity as the original #6 did.

I found antique battery labels out on the web and printed one and slipped it on the replica.

I don't know why the British folks call it a Flag Cell but in the USA it was used for automobile ignition and telephones originally. The British did make the clock.

The little silver contact pin is insulated on one side so it only provides current in one direction of rotation when it rotates past the contact flag. When it is all adjusted proper it will come to rest with the contact just touching the pin such that it will self start when you hook up the battery wires. I don't know if polarity is important but I always hook it the same.

I haven't modified my Eureka except for the replica battery which is a replacement for a #6 and sits in the mount in the bottom.

I haven't worried about contacts as I have a spare set I got from TimeSavers which I believe were from Peter Smith in the UK or from Horoligix. My clock has been going as described for about 6 years (how time flys).

I also have a set of replacement glass discs as I have one in the back with a crack (still procrastinating)

I have replaced the batteries a couple of times and I believe the current set has been in since November 2019.

When I fist got my clock it gained a good 20 minutes in a day. I found the hair spring tail was a little loose in the clip so I slid it an arbitrary amount. Then it wouldn't run until I re positioned the Balance with that tiny watch screw on the spring Colett that can't be reached easily.

As I sit here and watch it swing about 362 degrees, I am guessing the batteries need changing but I am patiently waiting.

I let it run about 1 minute slow per month as it is easier to move it forward than stop the balance.

Some people put in the diode, some use a pulse regulator circuit. I wear a mechanical wrist watch and am happy with the old technology.

One of the original issues is that the #6 drycell was prone to leak acid and that would eat away the battery retaining clamp in the bottom.

good reason to change the batteries often.

Jim
 
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praezis

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Feb 11, 2008
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Very good spark protection, contact erosion protection and overvoltage protection is achieved by a resistor 220 … 330 ohms instead of a diode parallel to the coil. This was already known at Eureka inventing times - but not to ist makers :(

Jim, if you prefer to stick to old technology, I wonder why you use modern IC electronics in your clock for regulating voltage and amplitude?

Frank
 

sophiebear0_0

Registered User
Nov 5, 2012
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Spark Quench

Good point Frank

The attached link gives some very useful information on spark quenching - and indeed recommends a parallel resistor as the bet solution.

Both ATO and Reform did use a resistor in some of their base case design. These clocks were made some 10-20 years after Eureka. I have also seen a capacitor used in a Reform-type movement.

ATO used the resistor in the horizontally mounted leaf spring clocks. I don't believe they were fitted where the leaf springs were mounted vertically. They were also not used in ATO's with rocker contacts, where the contacts were designed to be self-wiping.

As far as I'm aware Bulle did not use spark quenching in any of their designs. The pin & fork were designed to be self-wiping. Other e-m clocks such as Poole, Barr and Brillie do not use any spark quenching as far as I'm aware.

This is my best understanding, but am willing to be corrected !

Regards,

Peter
 

praezis

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Feb 11, 2008
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Hello Peter,
the lengthy article in your link tells it all, also points to the disadvantage of diode use.

Ato, Bulle, Brillie have low currents flowing (about 1 mA) and have coreless coils. They store low energy only. Nevertheless I saw >100 Volts back EMF on my Brillie.

Eureka current is 70 mA @ 1.5 Volts, but most run them on higher voltage, as we can read here repeatedly. Eureka has a coil with iron core. This results in much higher energy stored in its coil.
I suppose, the resulting back EMF is limited by the old and brittle laquer on ist coil wire only. More than a good reason to protect coil and contact by adding a "modern" resistor.

Eureka_resistor.jpg

Frank
 
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Lamela

Registered User
Jan 20, 2020
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Thanks, Frank for your photo and comments.
I will also attach such resistor to the coil of my Eureka. I must only to find something more contemporary to the clock, not so modern :).
Now I am trying to drive it from two 1,2 V rechargeable D-type batteries in series giving approx. 2,5 V when fully charged. Results seems to be interesting.
Jerzy
 

sophiebear0_0

Registered User
Nov 5, 2012
93
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Frank

You're right that the different designs of electrmagnetic clocks use different coil type and draw different current. However I can't see any obvious trends or logic.

The ATO clocks all have similar coils and resistance (low current) yet the vertically mounted contacts do not have a resistor, whereas the horizontally mounted contact do. Also Barr and Poole magnets have solid core and draw relatively high current and have no spark quenching fitted.The Reform-type movements are again solid core applications with relatively high current. There are a number of very similar designs which use: a resistor; a capacitor; or nothing for spark suppression.

I do wonder whether the reason for omitting a resistor was the fact that they use a little extra power and that battery power was relatively expensive to provide in the early days ? But the additional power consumption would be relatively low, so it doesn't seem to be very likely.

I do think a diode is a viable option for the Eureka - and it has certainly been used successfully. The potential downsides of using a diode noted in the earlier link I attached (ie undesirable magnetic pull & polarity issues) probably don't apply to the Eureka clock if the diode is properly installed. The attached restoration from Horologix uses a diode, so I suspect it is a reasonable approach.

Solely from a performance perspective, would you expect a resistor of a diode to perform better in the Eureka application ?

I agree with Jerzy that if he wants to exploit "technology of the day" then a vintage resistor is the way to go

Best regards,

Peter
 

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praezis

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Feb 11, 2008
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Hi Peter,
imho reasons for no resistor/no spark protection are:
1. low current clocks get not much harm without one. It is not really needed, but with will be better.
2. Manufacturers had no knowledge of electric issues (e.g. Eureka)

I do think a diode is a viable option for the Eureka - and it has certainly been used successfully. The potential downsides of using a diode noted in the earlier link I attached (ie undesirable magnetic pull & polarity issues) probably don't apply to the Eureka clock if the diode is properly installed. The attached restoration from Horologix uses a diode, so I suspect it is a reasonable approach.
I beg to differ.
It applies especially to Eureka type clocks: with optimal adjustment, the drive pulse will stop just in vertical position of the coil or short before. A diode will prolong current flow in the coil and magnetic attraction beyond that point: braking to the balance wheel and lower amplitude occurs.
This is no issue with Ato, Bulle, Brillie clocks.
I suppose, most people regard a resistor as 'too simple' and a diode as advanced and better. This is not true.

Jerzy,
admitted, my smd resistor is a rather modern part, but it is not visible.
Bulle1.jpg
For old look, you could use a small wired resistor and paint it black.

I found the rate of Eurekas to be very inaccurate and highly dependent on amplitude. Maybe rechargeable batteries are not constant enough to give a constant rate?
Most owners who report good results use a voltage regulator to keep amplitude stable.
I use a controller that can be hidden in a replica battery in the same way. It keeps my Eureka to < 3 sec/month.

Frank
 

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Lamela

Registered User
Jan 20, 2020
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Hi Frank,
As 1,5 V gives too low amplitude for stable operation, I have to find other solution. Of course, some modern stabilized power supplies will solve the problem easily, but I am trying to avoid electronics from the principle. So I decided to check the batteries connected in series. Typical D-cells give voltage over 3.0 V, and the amplitude is excellent, but the power drain is 4 times higher - it may be not good for contacts and time of operation. The rechargeable batteries have typical voltage of 1.2 V per cell and it is possible to find on the market the D-cell up to 10000 mAh capacity. So it is the easiest way to decrease the voltage of connected in series cells, reducing the power drain in comparison with 3.0 V of approx. 30%. As connected, the balance amplitude is within the good range of 350 degrees, now I am observing the day stability.
I will check for several days the amplitude vs voltage (if it drops...) and maybe it is not a blind alley.
Jerzy
 

James McDermaid

Registered User
Apr 29, 2011
139
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Back-in-the-Day . . . . . The #6 dry cell or Flag Cell was quit stable at producing 1.5 volts. They were used in telephones and automobile ignition.

It seems to me they mad the clock to contain exactly one of these cells and it must have worked to some degree.

I don't find my Eureka all that bad at time keeping It is as good as a ST #1 Regulator.

My house is at a very stable temperature due to modern heat and AC. This clock was made in the UK and I know they like varying temperatures from recent visits.

The solid Silver contacts apparently resisted the arcing and lasted a long time. I don't know how educated the maker was on electronics but there were spark coils being made and used in 1906 for many things sch as auto ignition.

If I look at my clock in a dark room I can see a tiny blue spark at the contacts. I can hear a faint dull thunk on the power stroke along with the click of the ratchet.

It sits on my desk in front of me so I can marvel at it. :)

A real #6 was probably as stable as my fake #6 with the regulator. So I consider it a no modification.

It is what it is so I am trying to avoid improving old things with technology.

Jim
 

Jessk09

NAWCC Member
Feb 27, 2020
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By the balance wheel it shows the patent numb.and “1906”.that may be the year your clock was built.


Regards, 16th July
 

Lamela

Registered User
Jan 20, 2020
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I bought the Eureka with the missing dome, As planned, I have made a new dome to my Eureka as the replica of typical metal and glass cage, which can be found in Shenton book.
The top is brass cast, other elements are brass milled.

IMG_3535.jpg IMG_3536.jpg
I hope it looks great ! :)
Now you can find two dancing, noisy clocks at my shelf.
Jerzy
 
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