Author Topic: Equipment time indicators  (Read 358 times)

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Offline SeanB

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Equipment time indicators
« on: January 13, 2021, 06:17:37 pm »
Found i have a pack of these 26VAC 400Hx hour meters still, never used, still in the waxed paper wrapping. Been sitting since 1976, but still likely work. I did have some running as hour meters, using a simple driver, one 555 timer, adjusted to 400Hz, running off 12V, and driving an old 400Hz signal transformer that had windings that would give a 26VAC output on the one set of leads. Capacitor of around 33n on the secondary to sort of filter to a sine wave, and then the clock connected. Ran for over 35000 hours before the clock itself failed, and I never actually replaced it with one of these spare ones.
 

Offline BurningTantalum

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Re: Equipment time indicators
« Reply #1 on: January 18, 2021, 12:34:49 pm »
They must have been for aviation use.
BT
 


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