On Sat, 4 Aug 2007 20:06:33 -0700, azotic wrote:

"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.


They sell special inverter semiconductor blocks for VFDs, with six
transistors on one block packaged exactly for this application. They
show up regularly on ebay.

I think that microcontroller really is the heart of a VFD, it would
not be easy to program.

i