Setting up a VFD on lathe (with foot brake)

[telowe]

First post on here. Run my own shop making parts. Have a Milltronics VM4222IL, and just got this lathe. Have plenty of other machines only geared toward engine maching. Need help with a new lathe that we are adding a VFD to allow soft start, variable speed and to run on single phase. The lathe is a Hwacheon HL-460. The VFD is now wired in and uses most of the factory control circuits.
There is
Forward/ Reverse control from hand levers
Brake stops the motor
Off/On switch works
Open door switch
E stop
Here is the problem. When stopping with the hand levers, the spindle coasts to a stop as we wanted to. When using the foot brake, the spindle will stop, but once releasing the foot brake, the spindle starts again.
The control is using the For/ Rev option with continuously maintained switches from the levers. If using 3 wire control, the VFD needs push button signals for for/ rev. But the switches are maintained in this machine. Is there a switch that will bolt into the same location and be a pulsed output.
Any other ideas?
VFD is a FUJI 20HP mini unit. We have added a potentiometer for speed control. This lets us run the lathe between 50 -100% of spindle speed in each gear.

[Captain K]

How did the foot brake turn off the lathe originally? Should be able to make it work with existing switch. I have a few frenic minis, you should be able to set parameters to do whatever you want. What do you mean by pulsed output? Momentary switch?

[telowe]

Currently using the FOR/REV Run command. That command uses the FOR/REV pins and the CM (common). Which is OK with switches that maintain a contact (like the levers provide).
Need to use the 3 Wire hookup. Terminals X1, X2 and CM , but these need a 1 push switch (pulse) to work properly. Then I can wire the foot switch in as a STOP.
So looking to either figure out a way for the lever switches to make a pulse or thinking about using a latching relay on the foot switch and a reset button on the lathe.

[Captain K]

You should be able to set it up with an nc switch on the foot brake in the common wire. If there is a break in the common it should not restart until both fwd and rev are both off. You’ll find that 3 wire control on that drive uses 4 wires. Common fwd rev and enable. The stop wire goes in the enable wire. You might be able to set one of the x terminals up as stop too. I’ll look in my manual and see if we can figure it out

Is there a switch on the foot brake now?

Could possibly set an x terminal to 7 for coast to stop. Connecting it to cm would shut the drive down. I don’t think it will restart until fwd/rev is reset

[telowe]

You are correct to use the Brake as a NC switch and I can do that. The problem with the 3 wire is the Start lever continuously keeping the FOR/REV switch engaged. The switch needs to be like a finger push on a button for 3 wire operation.

[Captain K]

For 3 wire operation you use fwd,rev,cm and an x terminal set to 6. Page 5-51 in my manual. I have one set up for 3 wire, I’ll see what happens when you hold down start button and press stop. See my edit on post before yours too

[telowe]

Is there a switch on the foot brake now? Yes there is.

Could possibly set an x terminal to 7 for coast to stop. Connecting it to cm would shut the drive down. I don’t think it will restart until fwd/rev is reset. That is a good idea. Will try that tomorrow.

[The Metal Butcher]

Well I'm not sure I'm much use here, but congrats on the lathe! That's about all the machine I'd ever want. I can't imagine having one new. Someday.

[telowe]

Thanks. The lathe does cut NICE. The last lathe I had was nice Clausing Colchester 13x40 VS12, but this one is far above that one. I have seen some of your vids on YTube. Liked the chuck balancing vid.

[Noitoen]

The easy way would be to use the original contactor relays from the motor to signal the VFD. The motor connects to the VFD directly and all the controls from origin are kept. If it worked stand alone, it will work on the vfd

[rdfeil]

telowe , It took me a while, but I finally figured out what Captain K was talking about with the 3 wire control setting. If I am understanding the users manual correctly Cap K is correct. While at first read it seems that it would require momentary contacts for start and stop, I think he is right and you can use maintained contacts to do the control. The way it works id that you need to program an X input (I would use X3) to value 6 which enables 3 wire hold control. What this means is that with X3 active, IE: connected to CM through the brake switch with the brake not applied, the next FOR or REV signal the drive sees going active will be acted on AND HELD! This means that switching your FOR/REV lever to stop will NOT STOP the lathe with your current wiring. The only stop command will be the brake bar. It should be easy enough to think through the switches to enable the FOR/REV lever to stop the lathe also. Another way to do this would be to machine a V groove in the middle of the FOR/REV switch actuator that would open the X3 terminal when the lever is placed in the stop position. This new switch would be wired in series with the brake switch so both would stop the lathe. With this configuration to restart the lathe you would, with the brake unpressed, simply move the lever to the stop position and then move it back to the direction you need. Give it a safe try and see what you get!! Let us know.

[Captain K]

Noitoen has the better idea I think. All of my other suggestions should be considered through his lens. rdfeil got me to go back and look at OP. I finally understand the real problem. The footbrake interrupts the com wire, but as soon as its released the lathe restarts. I was confusing myself previously.

[Captain K]

I checked this morning. 3 wire control doesn’t work with continuous on signal. Stop button does nothing if I hold in the start button

[Captain K]

Duplicate post

[jmm03]

isn't there supposed to be a mechanical connection between the stop bar and the forward and reverse lever? Somehow it does not seem right that the lathe will start as soon as you remove your foot from the bar,(just relating back to a machine similar to yours with a stop bar) Jim