Quote Originally Posted by Neale View Post
I'm interested in this as my lathe currently runs from an inverter from an outfit that took an ABB inverter (380-380) and fiddled with it. This outfit, no longer in business, seem to have put some kind of voltage-doubler circuitry on the input. The inverter is excellent, but the problem is that the input circuitry cannot handle heavier loads and there is too much ripple so that the inverter trips out. It's a 5HP (4KW or so) inverter driving a 3HP motor so that bit is well within its ratings.

I keep wondering about finding a suitable 240-380V transformer as per m_c's suggestion but these don't come cheap. So the Ecogoo inverters look interesting, but I'm not sure what the performance would be like at 50Hz as I'm running a conventional 50Hz motor. The motor isn't suitable for rewiring for 240V, unfortunately.
the ecogoo is vector control- so gives great low down torque. - i drill 20mm diameter at 4000 rpm on my 24000 rpm spindle- never once stalled it.
also- for lathe you can use the 8 step preset speeds if required- so no need for variable control. and most induction motors are good for up to 75 hz with no problems- so you can up the frequency and get more speed at the same lower gearing.
with vfds running at lower rpm is where the current rises and creates more heat- then you have to force the motor with air cooling.