Standard Electric Standard Electric Weight Driven 12hr Master Clock

Discussion in 'Electric Horology' started by SlickRick, Aug 2, 2016.

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  1. SlickRick

    SlickRick Registered User
    NAWCC Member

    Jan 15, 2015
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    Hi Folks,

    I recently purchased a Standard Electric 12hr AR master clock. It has a Birch case, square dial and appears to be from the 1950's
    I think it is an interesting clock in that it will run for 12hrs without power utilizing the drive weight. The winding mechanism maintains the weight in the full up position during operation under power. See attached for more information.


    Unfortunately, the previous owner must not have been able to get the winding relays to operate, so he ran the 24v AC power directly to the limit switch. This works but the motor ran every few seconds instead of every minute. Consequently, he burned huge pit in the limit switch contacts. I was able to polish what was left and rotate them so that a different portion is in contact. I think that should be fine for now.
    Unfortunately, though the relay logic is not working. The relay contacts on all the relays are carboned up from many years of use and need some TLC.
    There is a brief schematic in the bulletin but none of these relays are marked on the panel. And some of the wiring has been "modified". I think I can work it out eventually, but I was wondering if anyone else has experience with these clocks. Is there a detailed wiring diagram out there anywhere?
    Attached is the bulletin #110 that came with the clock. It contains some information about the operation of the clock.

    I will post some pictures of the clock soon.

    Thanks for your help in advance.
    Rick
     

    Attached Files:

  2. eskmill

    eskmill Registered User
    NAWCC Fellow NAWCC Member

    Aug 24, 2000
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    SlickRick is fortunate to have the Bulletin with sample schematics for the variations of this unusual SET master clock.

    With the sample schematic drawings, a circuit tracer and hours of point-to-point inspection and graphic notes, he could create an actual working wiring diagram.

    I think, the best place to start is to "un-do" any obvious alterations to the original wiring as supported by the data in the factory bulletin. It is important to note that the clock has an AC circuit for the motor and a DC circuit for controls.

    The contacts in the movement should be very carefully cleaned and burnished. Usually these contacts are delicate thin buts of platinum metal and unlike the robust relay contacts which can be brushed.

    It would be wise for SlickRick to make a careful study of the movement and its contacts to learn how the several contacts in the movement operate.

    'Doubt that SET sold very many of these master clocks....I've not seen one....it is certainly unique.
     
  3. SlickRick

    SlickRick Registered User
    NAWCC Member

    Jan 15, 2015
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    Hi Eskmill

    Thanks for the reply!

    Yep hours of point to point has been the task so far. And I have made some progress on building a working diagram. Which I will later draw in CAD and share with the community. I am amazed at the rats nest of wiring on the backside of the panel. No combed wire bundle on this clock. Just point to point wiring through holes made in the panel makes for slow going. Also the wiring doesn't exactly match the simplified diagram. Last night I managed to get the motor running only to have it suddenly stop. I found that the grease in the bearings had hardened up. So last night I disassembled the motor and cleaned the bearings. Tonight I am reassembling the motor then back to the wiring.
    The clock history website has a picture of the movement and electronics here
    The contacts on the movement look to be in good shape. I don't really want to touch them for now until I get the logic working. Slow going but I will keep you informed of the progress.

    Rick
     

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