VFD Remote For Basic Controls Questions

More annoying VFD questions from me.

If anyone remembers, I had a WEG VFD on my lathe that wouldn't allow S/V torque if the carrier frequency was set to 15KHz. I came across a good deal on another Hitachi WJ200 so I bought it. It doesn't have the limitations that the WEG has. In with the Hitachi, out with the Weg.

I'm getting the parts to remote control it.

First question is how to wire an emergency stop. As well as stopping the lathe in an emergency, I need to prevent the lathe from being accidentally turned on while working the chuck or moving the belt on the step pulley.

One youtube video suggested interrupting the power leg going to the forward/stop/reverse switch. I'm using the existing control lever that's on my carriage. It's a 3 wire setup. Is that a good way of wiring an emergency stop?

Doesn't your VFD manual explain about 2 and 3 wire control.

VFD 3 wire control - Google Search

Yes and I understand that. What I'm not clear on is how to wire an emergency stop switch. That was my question.

My manual covers that as well but it's a bit confusing to me and I don't want to do it wrong.

ptsmith said:

Yes and I understand that. What I'm not clear on is how to wire an emergency stop switch. That was my question.

My manual covers that as well but it's a bit confusing to me and I don't want to do it wrong.

Click to expand...

First, maybe clarify what lathe and how you want the controls to work. For instance maybe you have a carriage-mounted lever where down = forward and up = reverse?

I have a few WJ200 drives but not on lathes and not requiring an estop but here are a few thoughts...

Now, p31 of the WJ200 manual describes how to wire this if you have the ability to wire the drive's control power to switches for each of fwd and rev.

Now, what do you want e-stop to do?

One obvious answer is to stop the machine. So to do that, just have estop be a normally closed switch also in series with the path from L to terminal 1 and 2 (again, see page 31).

However, you probably also want estop to prevent fwd or stop from resuming until the estop is released and the fwd/rev lever has been returned to the neutral position right? And you also probably don't want the lathe to start after power-off if the lever is left in fwd or rev?

Are you thinking of using GS1/GS2 to implement estop?

Phil

ptsmith said:

Yes and I understand that. What I'm not clear on is how to wire an emergency stop switch. That was my question.

My manual covers that as well but it's a bit confusing to me and I don't want to do it wrong.

Click to expand...

It appears that you want a emergency stop switch that disables the VFD. A couple of my VFD's have an input for that.

This example disconnects input power:

Wiring Example - Hitachi WJ200 Series Quick Reference Manual [Page 93]

I looked in you drive manual. The emergency stop function page is blank except for a message (To be finalized after TUV approval).

I have a Jet 13X40. It's belt drive. I put a smaller motor pulley on it and run the motor to 120Hz. Now I only have to change pulleys once and that's for speeds over 800 RPM. So I doubt I'll be changing it much, but it would be nice to make sure the motor can't be turned on while doing so. Also, a member posted a while back that he lost the end of his little finger by accidentally hitting the control lever while adjusting the chuck.

So for those reasons I'd really like to be able to "no ifs ands or buts" kill power to the motor.

Brandenberger said:

Now, p31 of the WJ200 manual describes how to wire this if you have the ability to wire the drive's control power to switches for each of fwd and rev.


Are you thinking of using GS1/GS2 to implement estop?

Phil

Click to expand...

I do have a carriage mounted lever.

I looked at page 31. Wiring the E-switch to "L" is how the guy was wiring it in the youtube video that I mentioned.

Does implementing GS1/GS2 require the use of the module shown in the diagram? That would get expensive, wouldn't it?

rons said:

It appears that you want a emergency stop switch that disables the VFD. A couple of my VFD's have an input for that.

This example disconnects input power:

Wiring Example - Hitachi WJ200 Series Quick Reference Manual [Page 93]

I looked in you drive manual. The emergency stop function page is blank except for a message (To be finalized after TUV approval).

Click to expand...

You're right. I was confusing the E-switch with another function that I will bring up later. Don't want to get too many questions going at once.

The G9SX-GS226-T15-RC module in that diagram is pretty pricey. I'm hoping there is a cheaper solution.

I just accidentally found this. External trip. Could this be used as an E-stop?

External Trip - Hitachi SJ100 Instruction Manual [Page 134]

ptsmith said:

You're right. I was confusing the E-switch with another function that I will bring up later. Don't want to get too many questions going at once.

The G9SX-GS226-T15-RC module in that diagram is pretty pricey. I'm hoping there is a cheaper solution.

I just accidentally found this. External trip. Could this be used as an E-stop?

External Trip - Hitachi SJ100 Instruction Manual [Page 134]

Click to expand...

That looks like "unattended start protection" on the drive he has (p 34 in the WJ manual).

In my reading of the manual you might be able to just turn the safety switch on (dip switch) then connect L to GS1 and GS2 via your normally closed switch. Then when you hit the switch you should see the drive stop and the motor glide to a stop.

Haven't tried this myself though.

The only time I physically disconnect power from a control circuit is when I am changing blades on a table saw.

Brandenberger said:

That looks like "unattended start protection" on the drive he has (p 34 in the WJ manual).

In my reading of the manual you might be able to just turn the safety switch on (dip switch) then connect L to GS1 and GS2 via your normally closed switch. Then when you hit the switch you should see the drive stop and the motor glide to a stop.

Haven't tried this myself though.

Click to expand...

Thanks. I have an external brake resistor. I would like the E-switch to also be an actual panic button. So I wouldn't want the motor to coast to a stop.

I think I'll just go with switching "L". It should do what I need to do.

rons said:

The only time I physically disconnect power from a control circuit is when I am changing blades on a table saw.

Click to expand...

Maybe you're too comfortable with other machines. Fingers between a belt and a pulley when the power accidentally gets turned on aren't going to fare well. Or at least it's a bit unnerving to me.