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Old European Synchronous Clocks at 50 Hz

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dalesr

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I have an old European Electric Synchronous Motor Clock that is running at 110 Volts at 50 Hz with no earth ground or fuse. I have grounded this clock and fused it. However, this clock is running fast since it is running at 60 Hz and the clock movement was designed for 50 Hz. I am going to convert this clock to run at 16 volts AC to make it safer by creating a new coil with the appropriate turns to have this motor run at this voltage. I will then purchase an UL approved 16 volt AC power pack. I will still have the problem with the frequency since this clock is designed to run at 50Hz. I am looking for a way to make this 50 Hz clock useable at 60 Hz using my 16 volt AC Power pack as the power supply. I do not specialize in electronics and only have a digital volt meter and a variac. Any help on this would be greatly appreciated.
 
Hi,

the division ratio of 60 by 50 Hz is exactly 1.2.

I purchased an 8-track player in the USA long ago and had the problem with the music being too slow. I just changed the belt transmission modifying the drive wheel by 1.2 of its original diameter.

The device worked well.

Boncuk
 
Replace its synchronous motor with a 60Hz one instead of changing its power supply. Any old clock can be the donor if you do not want to have it replaced at a clock repair shop.
 
The only way I can see to do this and maintain accuracy is to drive the clock with a H-Bridge that is switched from an accurate 50Hz oscillator. If you want it to lock to the 60Hz signal and maintain absolute accuracy over the day then you would need a PLL followed by a divider.

Do you have any technical information on the clock? Especially the synchronous motor.

Mike.
 
Replace its synchronous motor with a 60Hz one instead of changing its power supply. Any old clock can be the donor if you do not want to have it replaced at a clock repair shop.

Yes, by far the best solution.

Mike.
 
Of course the easiest way is to just replace the motor.

The only way I can see to do this and maintain accuracy is to drive the clock with a H-Bridge that is switched from an accurate 50Hz oscillator. If you want it to lock to the 60Hz signal and maintain absolute accuracy over the day then you would need a PLL followed by a divider.

Do you have any technical information on the clock? Especially the synchronous motor.

Mike.
Another way of doing this would be to convert the 60Hz into a square wave, filter the 5th harmonic to get 300Hz and divide by 6 to get 50Hz.
 
Mike,

I do not have literature on this motor. It consists of a coil rated at 220/50 Hz or 110/50Hz connected with an iron laminated core that has a pair of claws that drive a magnetised rotor. This rotor connects to the clock gear train which is based on 50 Hz. I am not certain how many poles but assumed it was a single phase two pole motor where the RPM is based on (f*60 /(n/2) where n is the number of poles. I would have a very hard time finding a new gear train that can run at 60 Hz. I like the solution of converting the 60Hz into a square wave, filter the 5th harmonic to get 300Hz and divide by 6 to get 50Hz. The input voltage to this circuit would be16 VAC/60 Hz and the output voltage that will feed the coil would be 16VAC/50Hz.

Will this output be a sinewave or square wave and does it make a difference for the coil? Is there a schematic that I can reference with this solution with the components/manufacturers required to build this? Do I need an oscilloscope to test this circuit to verify output is 16VAC/50Hz?

-Ray
 
Are you joking, Hero999? That seems like it would be absurdly difficult. A triac circuit, 300hz resonant transformer, 50hz resonant transformer... trying to get the correct voltages and filtering everything without overheating it all seems like it would be more complex than a wall-wart with a crystal controlled driver.
 
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