Speed controller for single phase 0.55kw 2 pole motor?

[flanajb]

Can anyone tell me whether I can use a speed controller on a 240V 0.55kw 2 pole motor?

Was thinking of these 2 items.

http://www.ebay.co.uk/itm/Single-Ph...id=100033&rk=2&rkt=3&mehot=pp&sd=251721939023


http://www.ebay.co.uk/itm/4000W-Hig...a&pid=100005&rk=3&rkt=6&sd=201280799304&rt=nc

I just want to be sure that by using a speed controller I don't end up damaging the motor

 

[RogerP]

As far as I'm aware to properly control the speed of an ac induction motor you need to change the frequency not the voltage.

http://www.engineeringtoolbox.com/synchronous-motor-frequency-speed-d_649.html

 

[CHJ]

You can not change the working speed of a single phase induction motor*, the speed is governed by the mains frequency and the number of poles.

If you use a 'speed controller' intended for universal motors (brushes-commutator) and lighting then the motor will not have enough energy to keep its poles in sync and it will go into excessive magnetic slip mode and apart from power output dropping off rapidly it will start consuming excessive current and overheat.

*well you could if you ran it on an electronic phase changing invertor but it will not provide adequate power and will draw excessive current as it slows down.

Induction motors control a big percentage of the current consumed when up to speed by acting as a generator in their own right which balances the incoming current. (Back EMF) The reason why a motor starting up consumes a much higher current until such time it is spinning fast enough to generate.

 

[flanajb]

Many thanks chaps. Always really helpful!