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Old 21st Nov 2022, 4:15 pm   #1
Jockmacrea
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Join Date: Sep 2022
Location: Denholm, Scotland, UK.
Posts: 9
Default Only 12 Minutes in an hour ?

I was given an old Brass cased Slave Clock by a friend of mine. The two coils to activate the impulse were fried! I had these rewound.
I then started to develop my own drive circuit and also found a host of information on the web.
Finally, I constructed a Crystal controlled 1 second timer driving a relay which reversed the polarity through the coils. The two coils are connected in series with no centre tap.

After a few popped transistors and corrected wiring, it worked!

Now here's the real problem,
There are two hands on the clock, one big one and one wee one, the wee one is fitted onto the shaft first and then the big one which is secured by a small circular threaded nut. when securely mounted there appears to be enough room for a third hand

However, when I run the clock, the big hand takes precisely 60 seconds to go 360degrees, the wee hand takes precisely 12Minutes to complete 360degrees.

It would seem there may be an issue with the gear train? but I cannot see where it may have been mounted. This is all very strange; can anyone suggest where I may have gone wrong. I'm sure there are more that 12minutes in an hour!!!

Even if an extra hand was fitted how can that alter the 12-minute hour??

I'd be grateful for any assistance.
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