AC sync motor control

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My slate and acrylic TT is nearing completion. I decided that an AC sync motor seemed the best solution, but wasnt aware how complex they could be to control.

My brother said he would work something out for me and a few week later came back with the following. Just waiting on a few parts for Mouser and he needs to finish writing the software.

You can adjust voltage and frequancy and it has a boost feature to get the big platter going.
 

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If you had manual switch between 33 and 45 rpm, all you would need is a couple of capacitors plus a couple of resistors if you used a low voltage motor. Now of course you get a lot more flexibility and control of the speed, but a stable hook-up of a synchro motor can be very simple.
 
Don't want to denigrate an energetic DIY effort, but variable speed soft start single phase motor drives are now a component. Search NXF25 at newark.com for a Cutler Hammer 1/3 hp drive for about $140. Hammond organs drive the second phase of the synchronous motor with a 3 uf run capacitor. I have been eyeing one to add varispeed to my H182 organ celeste vibrato, a la improving the imitation leslie effect with the stereo vibrato to have the fast-slow ramp up and down feature. However, I have a surplus old tech 1 phase drive I'll probably use instead.
 
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