"Cursitor Doom" wrote in message
...
On Tue, 15 Jul 2014 23:44:03 +0100, The Natural Philosopher
wrote:

On 15/07/14 23:26, Cursitor Doom wrote:
On Tue, 15 Jul 2014 15:03:43 -0700 (PDT), robgraham
wrote:


Ummmm - if it's an induction motor, which you would be able to see by
the plate on the motor showing an 'rpm',
you could destroy the controller and possibly the motor. Induction
motors are mains synchronous and don't like
'dropping out' of that with overload or low voltage.

Is that a definitive method of identifying such a motor, then? A fixed
RPM shown on the plate?

No commutator.

And a capacitor starter.
brushed motors are in general NOT induction motors.

So is it the case that to know for sure, you have to take the damn
thing to bits?? That seems daft. They really should put something on
the plate to save aggro and for the avoidance of doubt!



If it's an induction motor.
Assuming you are in the UK the speed will be either just under 3000rpm ,
just under 1500rpm or just under 1000rpm.
This is because we have 50 Hz /3000 cycles per minute mains supply.
You are very inlikely to come across anything else.
99% of motors are induction motors because they are cheap to make.