On 2010-02-18, Bob Engelhardt wrote:
I have a 1 HP 3 ph motor that I don't want & nobody else does either. I
also have a VFD that will go to 400 Hz. The recent discussion about the
rpm limits of motors prompts me to see what happens.

So I'm gonna' hook up the motor, crank the VFD to 400 Hz & stand back!
But I thought that I'd give you guys a chance to make predictions. What
do you think will happen?

I think that the shading coils will fly out of the slots in the
rotor -- assuming that you start it at 60 HZ and then take the speed up
at a rate that it can track. I suspect that *starting* it at 400 Hz
would leave it not able to spin up - but I could easily be wrong.

Bob

Oh - the motor is 1755 rpm @ 60 Hz = 10500 @ 400. It is older & dirty
inside. The bearings? I dunno - it spins pretty easily.

I think that the bearings will be fine -- at least until the
rotor spins apart.

Enjoy,
DoN.

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