* * * * O.K. *What kind of switch is it?

* * * * If a "drum" switch, with a lever moving from "REV" to "OFF" to
"FWD", and a three phase motor, you should expect three wires in, and
three wires out and the switch (with line three phase, not with the VFD)
goes between the line and the motor. *One line is simply set up for
"CONNECT/OPEN/CONNECT", while the other pair are set up to be straight
through in forward, and swapped in reverse. *But this is six wires. *And
you can use one of thet swapped input wires as the COMMON for the VFD
and the two swapped motor phase wires to go to the FORWARD and REVERSE
control points on the VFD.

I'm not sure what sort of switch it is. It's integral to the casting,
and I have not found a way to remove it to review the actual
contacts. The two extra wires don't seem to ohm out to anything
useful that I can find. For all I know they don't go anywhere. The
three I have identified will work quite well for the FWD/REV function
on the VFD.


I have a 7.5 hp on the VFD for now. *It seems to have pretty good
torque all the way down to almost stalled (1Hz).

* * * * Yep -- but run it too long at those speeds and it will overheat
-- unless you have an external fan which runs full speed all the time.
The motor's own fan is just not moving fast enough to cool itself.

Yes, very true. And a good reason to keep the backgear so the motor
speed can be kept up a little bit, while dropping spindle speed to
nearly stall.



* * * * O.K. *As long as the fan does not die. :-)

It does have a thermal protect, so if the fan did die the drive would
eventually shut itself down. I could add an additional fan easily
enough. For that matter, perhaps an inverse speed sensitive fan for
the motor too. Shouldn't be too hard with some sort of comparator
circuit...

Anyhow. Thanks for the input guys.

JW