The output of a VFD should be wired directly to the motor with no
contactors, switches, or other circuit breaking elements between the two.
I'm told that VFDs don't like being run to an open circuit. You can run
wires from the lathe run/off/reverse switch to the control inputs on the VFD
to provide those functions and most VFDs have inputs for an external
potentiometer should you desire to control motor speed that way.


wrote in message
oups.com...
I am getting ready to put the VFD on the lathe and had a question.
Should I wire the VFD to the regular lathe circuit box or directly to
the motor. If I go directly to the motor I have no control over the
variable speed.

If I wire the VFD to the circuit box then I can use the analog inputs
for stop, reverse, frequency, etc. on the VFD and still control the
variable speed pulleys. Can I still power the lathe on using the
original button or do I have to use the VFD?

Will use of the VFD this way damage the contactors etc. in the circuit
box or damage the VFD?
The motor is a 3 phase/ 3 horse and the VFD is a 5HP unit.

Thanks