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Old 10th Oct 2010, 1:03 am   #17
Kat Manton
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Join Date: Jul 2005
Location: West Yorkshire, UK.
Posts: 1,700
Default Re: Motor type - synchronous or not?

Quote:
Originally Posted by kalee20 View Post
It's instructive to brake the motor spindle between fingers - you can feel the torque keeping the speed constant, and after a certain point, as synchronism is lost, the torque has a step change as the motor reverts to induction mode.
It just gets slower, there's no step in torque.

I also couldn't figure how the friction brake fine-speed adjustment could work in conjunction with a synchronous motor. I figured that, as the braking friction is increased, a synchronous motor would maintain constant speed until a point where it loses synchronisation (and stalls); which doesn't fit with how it works in practice.

Varying the speed of a synchronous motor could only be achieved by varying the frequency of the supply, I assume?
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