American Majestic Electric Clock; how to update/protect for safety?

Discussion in 'Electric Horology' started by Hudson, Oct 29, 2019.

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  1. Hudson

    Hudson Registered User
    NAWCC Member

    Jul 19, 2010
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    I am in the process of refurbishing an old spin start Majestic Electric clock. I have completed the mechanical part (the gear train) and am ready to finish the assembly. The movement required a good cleaning and one bushing.

    After reading posts on this board about fires caused by old synchronous spin start electric clocks, I thought I might pause and pose a question to those who are more electronically gifted than I.

    I will replace the power cord but otherwise the motor coil looks fine and was working before.

    What might I to do to this old clock to keep it from being a fire hazard?
    Should I wire it with a three wire (grounded) plug instead of the two wire?
    Should I install a fuse? And if yes, then what type and size?
    Any other ideas?
  2. flynwill

    flynwill Registered User
    NAWCC Member

    Feb 1, 2007
    Rolling Hills Estates, CA
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    If the coil is in good condition then the danger is pretty low. If the clock has a metal outer case then I might consider a 3-wire plug instead of 2-wire as that will provide shock protection, but not much protection from a potiential fire.

    As for a fuse, a thermal cutoff is series with and physically coupled to the coil is probably the best protection. (If you have ever opened up a modern coffee maker or similar heating appliance you will likely have seen one of these). Might take a bit of research (or trial and error) to determine the appropriate temperature however.

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