Huangyang gt series Vector control vfd ? Whats the difference?

[Voicecoil]

Hi Paulus

Thanks for reply. I might get one for my buffing machine which runs badly with a triac speed controller i'm using and the torque really drops off at lower speeds whe pushed hard.
Cheers

Andrew

I'm not suprised at that really, since to lower the speed of an AC induction motor, you obviously need to drop the frequency of the supply, not just drop the voltage, which is essentially what a triac controller does. Do you know what type your single phase motor is? - capacitor start* or capacitor run? I believe running the former of a VFD can be a minefield presumably since the centrifugal switch that disconnects the starting capacitor won't necessarily work if the motor's running at a lower speed than normal. And with the motor run capacitor, the value will be chosen to give 90 degrees phase shift between the2 windings at the normal 50Hz mains frequency (you need this phase shift to create a rotating magnetic field which the armature "chases": changing this frequency will presumably change the phase shift generated by the capacitor and hence reduce motor torque. That said, some quick Googling revealed revealed a couple of manufacturers that make VFD's specifically for single-phase motors (Leeson in the USA being one), so there must be some goodness in the idea. If you find one that works I'd be interested to know so I can up the output of my side channel blower: designing one shouldn't be too difficult particularly if you were to remove the capacitor from the motor and feed 2 90 degree phse shifted signals direct from the VFD, but I have lots more pressing projects!