"Grant Erwin" wrote in message
...
Start with your output phase, your "power semiconductors". If you can find
some of those that meet your spec at a price point you can live with,
that's one thing. I'm guessing that buying a small handful of them will
get you a price much higher than an entire VFD made by TECO or someone
else.

Igor, I'm still waiting for that $47 1hp VFD new on ebay ..

Grant

Agreed the power stage is the heart of a vfd, i have a variety of mosfets,
igbt and scrs
to play with. This will be a learning experience, been reading all the
available information
from the semiconductor manufactures and online textbooks, now i would like
to experiment
with some of designs i studied and test some of my own ideas.

Best Regards
Tom.