The difference is in the features.

Glancing at the FM50 and FM100 spec sheets at

http://www.tecowestinghouse.com

I noticed that the FM50 is goes up to 120 Hertz and the FM100 goes up
to 400 Hertz. Also the FM100 has programmable digital inputs and
outputs, etc.

The bottom line is you don't want to run your motor much over 60 Hertz
anyway unless you know its maximum rated RPM or you don't care if the
armature flies apart. Also for your application digital I/O is a
waste. I would get the simplest model.

Spending money on sensorless vector might be worth considering for
your application, though, because you get a much wider speed range
without loosing torque at the low end.

If you use more than one motor with the same drive, make sure the
drive cannot be disconnected from the motor while the motor is
running. This is bad for your drive the way missing a shift while
drag racing is bad for your car engine.

(T.Inoue) wrote in message . com...
Ok, I've read hundreds of messages on VFD drives and am trying to
decide upon a unit. I'm a bit confused about the relative merits of
the different models being advertised and was hoping somebody 'in the
know' could help.

what's the diff? Why the big price differentials? I don't see whether
some are vector drives or not. the information is pretty spartan.

All are 3HP, 220V 3-phase output
TECO FM100-203-N1, $295
TECO FM50-203-N4, $407
TECO FM50-203-C, $245
Hitachi L100-022NFU, $300
LG PS-C21030, $309
Hitachi SJ100-022NFU, $385 (sensorless vector control)

Any thoughts would be appreciated. I'm looking at driving a Mill and a
Lathe off of it, not at the same time. Very different load types,
minimal heavy work will be done.