Gentlemen,

I bought a Hitachi SJ200-022NFU2 model, 3 HP VFD to control my "new"
mill, which has a 2HP 3 phase motor.

This model, a "constant torque" VFD, is versatile and sophisticated,
and contains control options far beyond my needs and expertise.

I have carefully and almost completely read the owner's manual. The
basic installation is simple enough. You bring in the 2 legs of 220V
single phase from a 30 amp fuse or breaker, and connect these to
inputs 1 and 3. You ground the mounted VFD and the mill motor in a
star pattern. You connect the appropriate 3 outputs from the VFD to
the motor.

You go through an initial programming sequence, setting up certain
basic parameters. You power up the VFD. You verify certain that
certain pre-conditions are met and that certain LEDs are on or off on
the keypad. You take a deep breath, make the sign of the cross, and
press START.

After that the going gets sort of tough. Here are a couple of things
I don't understand. I will humbly accept your guidance.

First, it is my understanding that it is possibly fatal to the VFD to
switch the motor on or off from the mill's own on-off switch, or to
otherwise control the mill (instant reverse for example) EXCEPT
through the VFD's programmable circuits.

This leads to the following questions:

1) Do I remove the mill's on-off switch completely or otherwise wire
it permanently in the ON position?
2) Do I similarly wire around the wires going to and from the mill's
FORWARD - REVERSE toggle switch and re-route these wires to the VFD's
programmable inputs/outputs?

There was previously some discussion here about whether a VFD can
adequately handle the mill's instant reverse. However, upon careful
reading of the manual the VFD does seem to have a programmable "node"
that allows for this. Apparently this can be tweaked a couple of
ways. One of these involves installing additional resistors. Another
SEEMS to provide for programming the injection of a DC current into
the motor to stop it from coasting. I think these two things are
related but I'm not sure.

I think I can get the thing installed this weekend so that it will at
least start and run. However, my brain is a lot murkier as regards
these programmable controls.

Thanks to one and all.

Vernon