C. Bohmeyer & Co. master clock movement

Discussion in 'General Clock Discussions' started by kdf, Nov 15, 2013.

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  1. kdf

    kdf Registered User

    Aug 26, 2011
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    Here is one monster clock movement. It belonged to master clock, I suppose made by C. Bohmeyer & Co. in early 30-ies (or even earlier). Plates are 3mm thick, dimensions are cca. 170x180mm. Pendulum is cca. 1m long and bob is very heavy, about 6.5 kg. It has strange little motor for weight winding, and there are some sort of planetary gears in the cable drums. Very interesting construction, very robust and high quality as far as I can see. It can be wound up manualy too. Here are some pictures...
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    Attached Files:

  2. Tinker Dwight

    Tinker Dwight Registered User

    Oct 11, 2010
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    I would say that it was clearly pre WWII maybe even
    pre WWI. No one would have made such clunky motor
    after WWII.
    Tinker Dwight
     
  3. eskmill

    eskmill Registered User
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    Aug 24, 2000
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    The moulded capacitor part of the spark suppression network shown on the motor is of the type made circa 1940 and later.

    The "clunky" appearing motor is of the type very commonly used on European master clocks. They are very reliable and servicable.

    The pendulum bob is of the style commonly used on Bohmeyer and many German master clock.

    I have no thoughts about the planetary gears within the cable drums.

    Obvious is the need for two trains. One of the escapement and hands motion, the other to commutate alternating polarity impulses for slave clocks most commonly used in European master-slave systems.

    The movement is typical of highly reliable German made master signal clocks.
     
  4. kdf

    kdf Registered User

    Aug 26, 2011
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  5. Tinker Dwight

    Tinker Dwight Registered User

    Oct 11, 2010
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    Now that you mention it Les, look at the numbers below the voltage
    rating, I bet that is a date code. I can't make out the second half but
    the first part starts 47 which is most likely for 1947.
    Tinker Dwight
     
  6. kdf

    kdf Registered User

    Aug 26, 2011
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    0,1 mf + 100Ω
    500 v=
    4731
     
  7. Tinker Dwight

    Tinker Dwight Registered User

    Oct 11, 2010
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    Most likely the capacitor was made in the 31st week of 1947. It
    may not be original with the clock but I suspect it is. The clock
    would have been made a year of two later.
    Tinker Dwight
     
  8. kdf

    kdf Registered User

    Aug 26, 2011
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    At last - case is finished (by the professional carpenter), and yesterday I managed to complete this clock. In the meantime I made dial and some other pieces...
     

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  9. eskmill

    eskmill Registered User
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    Aug 24, 2000
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    Your C. Bohmeyer master clock appears in the photo to be a fine furnishing for a high-class business office.

    I note that the electric motor was made to be used with 24 Volts Direct Current. Are you using the clock as a manual wind-up or do you have the movement wired to use a battery or transformer/rectifier.

    I note that the movement was made to supply alternating polarity direct current for slave clocks. Would they be of the minute alternating type or half minute type?

    It is not often that we find these industrial type clock movements installed in such fine glass standing cases.

    I ask too about the pendulum which now I see, has a bob more suitable for a standing clock.

    Good work to save a fine old industrial clock movement in useful household or office furniture.
     
  10. kdf

    kdf Registered User

    Aug 26, 2011
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    It is wired and it's motor winds up weights every hour or so, by one inch. It wouldn't be convenient for manual winding because it can run only about 15 hours. It's working on rectifier, and in case od power outage clock can run for about 10 h so it doesn't need battery backup. Motor draws very low current, 50-60 mA.
    Slave clocks are using alternating polarity impulses on every minute, as usual for german and Europe clock systems (except maybe in France and Swiss). I didn't connect any for the time being.
    Pendulum bob is not original, but works well. Interesting thing - original bob is about 10 times heavier than currently used, but clock is keeping time very well.
     
  11. Albra

    Albra Registered User

    Oct 17, 2006
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    Greetings kdf,

    this is a very interesting and rare movement. Thank´s for sharing!


    albra
     
  12. kdf

    kdf Registered User

    Aug 26, 2011
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    I think that they are not so rare here in Europe...
     
  13. Risto

    Risto New Member

    Sep 15, 2014
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    Hello.

    This is a Bohmeyer clock. I have one too, with a L.M. Ericsson plate on it.
    It's a nice clock ans worked well so far, but now I have confronted a problem. Both weight drums are not rewound to their up position any more. The right one, taking care of the clock ticking is being left lower and lower after each rewinding sycle. It must be lift manually every now and then. The left weihgt drum, that takes care of the train (= big cogwheel), is working perfect and rewounds to its up- position fine.
    What is wrong with the clock? Is it an electrical problem or what?
     
  14. kdf

    kdf Registered User

    Aug 26, 2011
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    Can you post some pictures? I would say that it's some mechanical problem, not electrical. Motor is winding both drums in the same time, they are connected via some wheels. Maybe some wheel is slipping on the shaft, or something like that...
     

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