Quote Originally Posted by Ross77 View Post
I thougt you can control the speed of a 1ph motor with a triac based controller. seen them for about £10

Do these only control the speed and therefore have reduced power as well?
Only if they are PM motors (permanent magnet). 1ph motors with AC field coils cannot be controlled this way as they are synchronous to the AC input frequency. PM motors are low-fractional HP output.

Quote Originally Posted by Ross77 View Post
Seen a couple of VFDs on ebay for £150. dose this seem about right?
Thats about right for a sub-1kw (.5 - 1HP) VFD. You must match the VFD to the motor.