looking for advice on new motors

[TotalSonic]

Greetings fellow Trolls:
Been a bit since I posted last, but as it looks like my mastering schedule is going to be a little lighter than usual the next couple of weeks I was wanting to put in some time towards my embarrassingly long procrastinated on project of restoring a Fairchild 523 record lathe. First step for me is sourcing a new motor. I am looking for either a quiet as possible 1800rpm motor that I can connect to the current gear box - which likely means DC brushless with a controller so I can refine the speed as needed OR finding something that could hook on to the turntable shaft for direct drive. Price is not necessarily an object but keeping this under $600 for belt drive or $2000 for direct drive is my general budget. Any suggestions for models (I've looked at general info from Bodine and Baldor so far) and sources for purchase is appreciated!

Best regards,
Steve Berson

[tragwag]

I don't have a lot of experience with motors like that, besides the Bodine ones for the 6Ns.
Could you possibly re-work your system to include a technics SP10 (mkII or mkIII)?
I think it would be much more reliable, and not terribly difficult to implement.

[markrob]

Hi,

If you are going to go with a direct drive setup with no gear reduction, you need a high pole count motor. Superior (Slo-Syn) makes single phase and 2 phase AC synchronous permanent motors with a shaft speed 72 RPM at 60 hz that can be speed controlled electronically with a VFD.

Here is some info on the operation:

http://www.industrial-electronics.com/emct_2e_5i.html

They are very similar in construction to the Lyrec motor used on some lathes. They are better than a typical stepper as they have a sinusoidal winding distribution and so should have much lower torque ripple when driven by a sine wave source.

I'm in process designing a drive for this type of motor. I have a used Slo-Syn motor due to arrive to experiment with in the next day or so. I'll let you know if it works out to be smooth enough (low torque ripple) for this application. I am also looking at re-purposing a ceiling fan motor to drive a turntable. They are also high pole count single phase AC induction motors (not synchronous) and are available at low cost. If I get anywhere with any of this, I plan to post the results here.

Let us know what you end up doing.

Mark

[TotalSonic]

Mark - thanks so much for your reply and info!

Best regards,
Steve Berson