Re: can this motor be made sync?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

At 02:32 PM 10/6/2005, Tesla list wrote:
> Original poster: "Dan" <DUllfig@xxxxxxxxxxxxx>
>
> What makes an induction motor a-synchronous, is the fact that the 
> armature is not magnetized. Period. if the armature does not slip 
> with regards to the rotating magnetic field, there would be no 
> induced magnetic field in the armature. That is why induction motors 
> run slower than synchrony. It's not because it has no flats. 
> Manufacturers would have thought of that already, if it acutally 
> worked. No amount of flats is going to fix that. I don't know where 
> that idea came from, i've seen it before on some website. I just chuckled.

Except that you CAN actually make a synchronous motor with an 
unmagnetized rotor...
Lots and lots of folks on this list have done it by machining flats 
on the rotor of an regular old induction motor.

It works much like a variable reluctance stepper, which also has an 
unmagnetized rotor.

Sure, you don't get the torque you'd get from a sync motor with a 
magnetized rotor (or a wound rotor, for that matter).  But, hey, you 
also get a motor that has non-zero starting torque, so it starts by itself.


> The only way would be to somehow magnetize the armature, but since 
> it is mostly aluminum, I don't see how you would do that.
>
> Dan