fechter said:Thanks for the link. Gives me a much better idea.
I've seen some pretty cheap VFD inverters made for line voltage. I wonder if it would be possible to modify one for higher current/lower voltage. It might make the whole setup pretty affordable.
I don't think it is so easy. line inverters normally work with a V/F algorithm, or they use some rough vector control to limit current, but they normally do not have a feedback from speed, and do not have a full model of the motor after a self-tune test (like Curtis does)
also, it is not the same working with 10 Amp RMS than 500 Amp RMS, everything becomes more difficult and critical
For continuing my experiments I bought an used Curtis 80V 550 Amp in ebay for about 650$ as my job does not leaves time for building my own controller, but I think I will do in future