Lathe friendly VFD?

I'd like to locate a VFD that would support all the controls
that are currently on my lathe.
It seems VFD's will support maintained contacts or momentary
contacts, but not both at the same time.
Some drives will support a remote panel, but then you can't
connect the lathe switches.
This is what I have and what I am looking for.
- Maintained Forward switch N.O. - Motor should run forward while on, turn
off while off.
- Maintained Reverse switch. N.O. - Motor should run reverse while on, turn
off while off.
- Momentary foot brake switch N.C. - Output to motor should cease.
VFD shouldn't have to be restarted. If one of the forward/reverse switches
were left on, they should have to be turned off, then on again to restart
the motor.
- Stop switch. N.C. - Currently in series with foot brake switch.
This one could cause the VFD to turn off, requiring a reset.
If one of the forward/reverse switches
were left on, they should have to be turned off, then on again to restart
the motor.
- Momentary Jog N.O. - Run motor in forward while closed.
- Remote panel showing frequency. It should also allow speed
changes.
Does anyone know of a VFD that will support these functions?
So far I haven't been able to locate one. I have a feeling
it doesn't exist.
Thanks,
Wayne
Reply to
Wayne
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You should hard wire these functions. You're talking about an E-stop circuit for the machine, pushbutton controls and a panel from the VFD for the display. If I could see your machine (to see exactly what you've already got, sounds like it mostly already there) this would be a very small job. Any controls type electrician should be able to do this for you.
Karl
Reply to
Karl Townsend
[Sorry, I hit send bfore adding this thought]
My BEST GUESS here is that you have a forward relay that engages whenever your machine logic enables forward operation. And a reverse relay whenever your machine enables reverse operation. You should be able to take a dry (unpowered) contact off these relays and send to the VFD. Get a remote wire for theVFD keypad so you can put it on the operator panel.
Karl
Reply to
Karl Townsend
Your guess is correct. The lathe logic board has the proper interlocks and does provide fwd/rev relays to the motor. I thought about doing what you suggested. It took me a day or so to realize there is a problem using the foot brake. When actuating the brake the fwd/rev contact is released ok. The VFD will then start ramping down the motor (power still applied) while I'm putting braking force directly on the motor. I kinda figured braking the motor with power applied is in the bad catagory. Bummer.
Wayne
Reply to
Wayne
I must be missing something. If you set the VFD for "coast to stop" , the motor power will be immediately removed when the forward or reverse relays drop out. There is no need to wire the foot brake sw. to the VFD. Of course, there will be no dynamic braking from the VFD, but you didn't have that before anyway.
Randy
Reply to
Randal O'Brian
This would certainly work. But I think I'd add a brake resistor for increase dynamic braking. Then, between the foot brake and the VFD, that thing will stop NOW! You will have to play with software setup in the VFD quite a bit here.
Karl

Reply to
Karl Townsend
I'm using a Toshiba VFD on a 15" Sheldon lathe, which had no braking provisions. I ran it once on a static converter, and it took a LONG time to spin down. I put a braking resistor on the VFD, and it now stops the lathe from any speed in about 3/4 second! I really like that. And, of course, there's no friction material to wear out this way.
I couldn't figure out how to set up the VFD to do latching forward and reverse, and non-latching jog all in the configuration. So, I had to add a pair of relays to latch the momentary for and rev buttons. The VFD even supplied enough 24 V DC to power the relays.
Jon
Reply to
Jon Elson
In case anyone is interested I found that KB electronics has one that works well. It is a model KBN2-2203-1. For the jog you need to add a diode over to the run. The only thing I don't like about it is the fan is annoying.
I also talked to a Mitsubishi rep that said they had a model that would work, but you'd have to reset if you used the foot brake.
Wayne D.
Reply to
Wayne
I have a Delta VFD-B (I have a 3.5 hp unit running my 2 hp metal lathe) that seems to have all the features you want - cost $200 refurbished from a distributor
(no, it's not the same delta as makes the tools)
Reply to
william_b_noble
Take a look at the Mitsubishi S500 series of Inverters - from what I remember, they do all that you require. But the documentation is fairly impenetrable.
Reply to
Gary Wooding
!My server will not let me quote the entire artile.
I have a couple Teco VFDs. Not sure if they will do all that or not, but a call to Dealers electric will get you the info you need. They have a couple guys there that know the drives pretty well. chuck
Reply to
Chuck Sherwood

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