Lathe friendly VFD?

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

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

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

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

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

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

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.

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)

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.

!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