Eureka Eureka Running Too Fast

Discussion in 'Electric Horology' started by Frank Manning, Mar 10, 2010.

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  1. Frank Manning

    Frank Manning Registered User
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    Nov 22, 2005
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    I have a Eureka clock that is running too fast. I have the end of the spring all the way up to the clamp. I have the adjustment turned all the way to the slow end and it is still running quite fast. What other adjustment do I need to make to slow it down? The total swing of the balance wheel is about 220 to 230 degrees.

    Thanks, Frank
     
  2. John Hubby

    John Hubby Senior Administrator Emeritus
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    Sep 7, 2000
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    Frank, here's what I check when these run too fast, in order of most likely problem:

    1) The advance pawl is picking up two teeth instead of one on the motions works now and then.
    2) Some or all of the poising weights on the balance wheel have been screwed all the way in.
    3) The balance spring has been shortened by someone. See the drawing and specs on Horologix.

    I have encountered all of these problems at one time or another, you may have already checked but there isn't much else that can cause these to run too fast.
     
  3. Frank Manning

    Frank Manning Registered User
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    Nov 22, 2005
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    Hi John,

    Thanks for your information. I looked at the poising weights and none are screwed all the way in. At one end they are farthest out and then each successive weight is in a little further. They are equal on opposite sides.

    I have watched the engagement of the teeth for only one revolution and it doesn't seem to vary; only one tooth at a time. However, I can't seem to get myself to watch it over a prolonged time.

    I checked the overall spring diameter relative to what is on Horologix and it appears ok. So, it doesn't appear to have been shortened.

    Does this just leave me with the option of moving out some of the poising screws in opposite pairs to change the inertia of the wheel? I really didn't want to get into that and possibly change the balance.

    Frank
     
  4. jkfabulos

    jkfabulos Registered User
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    Just a thought. What voltage are you using to power it? I believe it should be 1.5 volts.
     
  5. Frank Manning

    Frank Manning Registered User
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    Nov 22, 2005
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    Hi Jim,

    Yes, I am using two "D" cells in parallel to provide 1 1/2 volts. It is running about 20 minutes fast in 24 hours. I did open up the gap a little between the two wires on the adjuster where the spring goes through.

    Thanks, Frank
     
  6. John UK

    John UK Registered User

    Mar 25, 2006
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    My Eureka goes fast when the battery gets low and the arc declines. I know they should be reasonably 'isochronous', but there's a pretty good chance that over the 100 years since it was made the weights may have been tampered with - or the spring (which doesn't exactly look pristine) distorted.

    I suspect that to reset it to be isochronous with an (expensive) new spring might be the work of a lifetime(!), so I'm leaving well alone. I'm really not sure if there is a known 'method' to do this? I'm also not sure how much (if any) temperature compensation is built in?

    With a fresh battery it keeps time to about half a minute a week, and this goes on for several months before it gradually begins to gain as the battery weakens. When running correctly, the arc should be near 360 degrees. I have seen clocks run with much less.

    Its worth saying that Eurekas have a dubious reputation for timekeeping, but a stabilised supply would certainly improve mine based on what I have seen. Someone (Brian Mumford?) used to do a stabilised supply I believe.

    I use a single 'D' size Duracell which lasts over a year and for most of that time gives acceptable timekeeping in my eyes.
     

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