My first Bulle restored

Discussion in 'Electric Horology' started by praezis, Apr 26, 2020.

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    Just Two More Days
  1. praezis

    praezis Registered User

    Feb 11, 2008
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    My first Bulle Clock(ette) no. 58772: got it some years ago, not running, by never had the time to restore it.

    IMG_1111b.jpg IMG_1109b.jpg

    Now I had. What were its issues?

    Bulle0_i.jpg

    1. the rear part of the top connecting plate was pinched off.
    2. The suspension spring was repaired with steel blades!
    3. top hairspring was loose.
    5. silver spring making contact to the fork: missing
    6. the silver piece on the fork was worn down to the steel sheet, the isolating piece later and unshaped.
    7. Isochronism spring on one pin only, but still there.

    Work done:
    1. silver soldered the missing brass piece to the top plate
    2. equippd the susp. spring with artificial silk "blades"
    3. attached to the plate
    5. made a new spring from 0.2 mm silver wire
    6. replaced the silver piece and reshaped the other
    7. attached to the other pin (very very fiddly)

    The fork arbor was removed, fork repaired, twisted bushing carrying the pushing blades adjusted. Silver pin polished in my lathe. The movement I cleaned in US and lubricated few places with watch oil.

    The coil was ok, luckily.
    Also magnet strength was ok. I applied the test proposed by Horologix, but used an Iphone app instead of a compass:

    IMG_1115b.jpg IMG_1116b.jpg
    (photo shows another, weaker magnet)

    After assembling all parts: will the clock run? It did, from as low as 0.7 Volts it runs reliably.

    Curious, I made some tests using my software timing machine.
    I found an utterly poor current pulse on the scope window, contact pin and fork are more interrupted than connecting!

    Bulle_PCZW2b.jpg

    Also the strong influence of the isochronism spring became apparent. Rate at 1.2/1.5 volts, rating nut in medium position:
    without spring: -40.3/-40.9 minutes/day!
    with spring: -133/-98 sec/day
    more tension: -114/+64 sec/day
    less tension: -26/+7 sec/day

    Electric Clock Controller
    A device that I developed years ago and improved it in several stages. Inserted between battery and clock, it keeps the clock within quartz accuracy (or radio clock accuracy in Europe) by taking advantage of the escapement error. I use it to my satisfaction with Atos, Brillies, even Eureka.

    Bulle was still missing, and I had little hope to control a Bulle with its poor contact and wider rate variations compared to an Ato or Brillie.
    Today, after some adapting to Bulle's peculiarities, there is a special Bulle version and the above clock is running precise to the second for one week now :)

    IMG_1893b.jpg

    Regards, Frank
     
    Dave T and S_Owsley like this.
  2. whatgoesaround

    whatgoesaround Registered User

    Jan 22, 2008
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    Bulle had a flair for their designs, I like those lightning bolts, but more impressive, I think, than the clock are your engineering skills. Well done.
     
    Al Dodson and Dave T like this.
  3. praezis

    praezis Registered User

    Feb 11, 2008
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    Thank you, and yes, I like that electric lightnings design very much, too.

    Frank
     
  4. S_Owsley

    S_Owsley Registered User
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    Jan 24, 2011
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    Gosh, that's so pretty. I'm more of a wall clock guy, but I would find a prominent place for a clock like this. I'd love to have a Bulle. I have a mid-century Kieninger & Obergfel electromagnetic, but this is way more elegant.
     
  5. Uhralt

    Uhralt Registered User
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    Sep 4, 2008
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    Could you explain how your electric controller works?

    Uhralt
     
  6. praezis

    praezis Registered User

    Feb 11, 2008
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    Hello,

    I can measure rate and amplitude on the clock terminals. Errors are corrected by modulating the supply current.
    For more details I have some info for download here.

    Frank
     
  7. Uhralt

    Uhralt Registered User
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    Hi Frank,

    That's very interesting! I was wondering if the principle would also work on a Poole electromagnetic clock. My impression is that it likely wouldn't work because the pendulum gets its impulse not directly by the electromagnet but by a weighted lever that falls by gravity to push the pendulum. The lever is only retracted up by the electromagnet into a locked position. The force with which it falls shouldn't depend on the power supply of the electromagnet as long as it is sufficient to pull the lever back up. Do I see this right?

    In addition the clock runs on 4.5 V and the device is for 3V but I guess that could be overcome.

    Uhralt
     
  8. praezis

    praezis Registered User

    Feb 11, 2008
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    You are absolutely right.
    The device can control electrically driven pendulums only. Electrically wound clocks or driven by an electrically lifted lever are not possible.

    Frank
     
  9. Uhralt

    Uhralt Registered User
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    Schade! Ich haette gerne damit gespielt.

    Uhralt
     
  10. praezis

    praezis Registered User

    Feb 11, 2008
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    Ganz einfach: nur die passende Uhr erwerben :)

    Frank
     

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