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Circuit to send a 115 volt pulse every 60 seconds

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GHW

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I would like to build a device to replace a 3w, 115v, 1 RPM motor that activates a micro switch every 60 seconds, that in turn sends a 115 volt pulse to a clock mechanism for advancement. The clock was removed from an old school house and installed by my father at our old home place some fifty years ago. It adorns the cabinetry above the stove and is a center piece in our old home. Prior to the simple micro switch being activated by the 1 rpm geared motor, a mercury switch was positioned to tilt every 60 seconds causing advancement. The motor is badly worn, reverses itself on occasions, and stays extremely hot. My elderly mother depends on the clock and I would like to find or build a simple device that would take the place of the old motor & switch. Surely someone has an idea. Thanks for your time in this matter. gw321cya@gmail.com
 
It sounds to me like you might be able to use a LM555 timer circuit, triggering a relay every 60 secounds.
although I'm not sure if the 555 is presice enough to drive a clock, or which circuit to use.
there might be something here you could use/modify to your needs.

**broken link removed**

But again, get a secound opinion on it before you go any further.
 
For an accurate 60 second pulse, a 555 timer won't be sufficient.

There are two ways of doing this to the desired accuracy:
1) Use a crystal resonator (high frequency, say 32kHz), then divide this down using a ripple counter. Most RTC chips produce a 1Hz square wave from a resonator, so would require a divide by sixty circuit.
2) Do what the motor did, and get timing from the mains. Transform the mains to a suitable level (say 5vac), produce a square wave using a schmitt trigger (60Hz in the US), then use two divide by sixty circuits to produce the desired pulse.

Andy
 
Is there any reason you can't just replace the motor? They're under $10 new delivered on eBay.

There are plenty of ways to do it electronically; but unless you're up for the challenge, it may be more pain than it's worth.
 
Note you'll need a synchronous motor - something like **broken link removed** would be excellent.

Edit: although a 120V unit would be even more excellent :p
 
Last edited:
Note you'll need a synchronous motor - something like **broken link removed** would be excellent.

Just note that a 120V AC unit may be more suitable.
 
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