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

maybe I'm getting dense, but your question doesn't make any sense. I have a
logan/powermatic with a reeves drive and a VFD. the VFD is wired directly
to the motor as it MUST be. this is electrical and in no way affects the
operation of the reeves drive. I removed the contactors and barrel switch
and let the VFD do that work.

If this didn't answer your question, please clarify a bit......


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

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

Not too long ago we had a LONG thread from guy attempting to use all
the existing wiring and he wondered why it didn't work well. He wanted
to set the VFD and then put switchs between the VFD and the motor
ie use all the existing wiring in spite of the fact that the manual
says very clearly not to do this. Hook the motor directly to the VFD.
Do not put any switchs between the motor and the VFD!

If you want to use the existing controls; you will have
to look at the manual and figure out how to interface the existing
controls to your VFD. I have found that "3-wire" control interfaces
well with push buttons. Other schemes work better for drum switchs.

"Mike Henry" writes:
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.

The sensitivity of the vfd to "plugging" the motor on and off is
design dependent.

I don't have electronic controls hooked up on mine yet, I just use the
original BP isolator switch. My vfd idles until it sees the motor
load, then spins it up. When the load goes away, it switches back to
idle. I specifically asked the vendor about this, they indicated the
unit will handle it just fine- I'm just not fully taking advantage of
its motor accelerate/decelerate features.

Better check with your vendor- and especially confirm how your unit
will behave if there is a short to ground. Some vfd's will fail
catastrophically if any of the phases conduct appreciable current to
ground. For those that do, the situation can be mitigated by
constructing a chassis ground which leads thru a resistor and gfi
breaker so the vfd 3 phase can be cut out to prevent damage to the
personnel and equipment.

http://www.practicalmachinist.com/ub...?ubb=forum;f=3

has a few articles on the subject.

Gregm


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

william_b_noble wrote:
maybe I'm getting dense, but your question doesn't make any sense. I
have a
logan/powermatic with a reeves drive and a VFD. the VFD is wired
directly
to the motor as it MUST be. this is electrical and in no way affects
the
operation of the reeves drive. I removed the contactors and barrel
switch
and let the VFD do that work.

If this didn't answer your question, please clarify a bit......


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



Well William, my Sheldon has a mechanical variable speed drive and it
is adjusted via a gear motor. The gear motor is run from circuit box
off of a transformer apparently. So if I run the motor directly from
the VFD how to you suggest that I operate the gear motor without
running another run of wires to the transformer which is impractical???
Please let me know. Thanks, Steve

Well William, my Sheldon has a mechanical variable speed drive and it
is adjusted via a gear motor. The gear motor is run from circuit box

I am not familar with your lathe, but mechancial VS drives on clausing
and rockwell must be adjusted when the spindle is running. If your
little gear motor is 3ph, I would put in parallel with the main motor.
If the little gear motor is single phase, it might not like low frequency
or running from VFD power, so I would figure out a way to connect it to
single phase AC but try to interlock it with the spindle motor so that
it won't run unless the spindle is running. Some VFDs have outputs
indicating the drive is "at speed" that could be connected to relays
that enable power to the gear motor.

chuck

I dunno if this is too simple for ya, but there is a spot where 3 little
wires run into the spindle motor, take them out. Attach those 3 little
wires to the VFD input, attach 3 more little wires to the VFD output and
run them to where the first set used to go, on them motor. LEave the
gearmotor alone.
If your contactor is anything fancier than an overload heater you may
have to deal with that

wrote:
william_b_noble wrote:

maybe I'm getting dense, but your question doesn't make any sense. I

have a

logan/powermatic with a reeves drive and a VFD. the VFD is wired

directly

to the motor as it MUST be. this is electrical and in no way affects

the

operation of the reeves drive. I removed the contactors and barrel

switch

and let the VFD do that work.

If this didn't answer your question, please clarify a bit......


wrote in message
groups.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




Well William, my Sheldon has a mechanical variable speed drive and it
is adjusted via a gear motor. The gear motor is run from circuit box
off of a transformer apparently. So if I run the motor directly from
the VFD how to you suggest that I operate the gear motor without
running another run of wires to the transformer which is impractical???
Please let me know. Thanks, Steve

Well ourname....
That was a smart a@@ed answer from someone who hadn't even read the
question....
Sheesh.
Looks like Chuck understood the question..
Pete

actually, yes I did. What it looks like is the guy wants to know if
there is an easy way out.

the short answer is 'no'
come to think of it the answer is almost always no


One has to wonder if the mechanical variable stuff is going to want to
spin much faster than it does now...



wrote:
Well ourname....
That was a smart a@@ed answer from someone who hadn't even read the
question....
Sheesh.
Looks like Chuck understood the question..
Pete