Powerflex 4m Running Utility Pump

[jraef]

To add to jraef's last post , he didn't mention another problem with 1 ph capacitor motors and that is the speed range . The capacitor is used in series and is designed to provide a rotating magnetic field in the motor . The offset is fixed and therefore you will only have a limited range of speeds available and the motor will need to be started at the plate frequency before changing to the run frequency .
As jreaf says your much better off with a 3 ph motor .

My experience is, if you connect a VFD to a single phase capacitor start motor, you end up burning up the drive or motor before you get a chance to discover the speed issue...

But it was a good point worth mentioning, because it also applies to the other issue of "using an scr or triac controller". That only works if the motor is PSC or Shaded Pole.