[Phishaholic]

Guys
I need a little help with some troubleshooting..Here is what I was doing and what happened..

I was machining aluminum and using the midi to control the machine. The spindle was set with the S word to 4000, I made a couple passes and finished the Op and ended with M5 and M8. I moved the axises with the jog shuttle. I changed the tool to a slitting saw and set the S word to 900. I then typed in M3 and hit enter, when I did the GFI on the 110 outlet tripped.

I unplugged the machine and reset the GFI and plugged it back in, it tripped again. Next I unplugged all of the 110 devices including the PC from the back of the machine. and plugged it in, It tripped yet again.

So at this point I'm up for Ideas. I was thinking about disconnecting wires until it stopped tripping and go from there.

I wanted to see if anyone has experienced this problem in the past before I start that line of troubleshooting.. My machine is the older version with an analog drive.
Any thoughts or ideas would be appreciated! Thanks!!

Larry O

[Phishaholic]

Did a little more trouble shooting and when I removed wire 202 and 205 from Machine Control Board the breaker doesn't trip. The manual says that is a control board problem. Darn

[ViperTX]

So, Tormach recommends that you run a machine tool using a GFI?

Paul

[zephyr9900]

Paul, the main machine power isn't GFI. Power inlet for the auxiliaries (control PC, coolant pump) is recommended to be GFI. See section 2.6 in the Tormach manual. It says:

Both the 115VAC power and ground are autonomous from the main machine power and ground (230 VAC) in order to allow correct operation of the ground fault interrupter (GFI). The computer control of the coolant outlet is accomplished by an isolated relay.

It could be this isolation on the control board that has failed in Larry's case.

Larry, you might check to see if there are any loose wire strands poking out from any of the wires connected to your control board. On my Series I machine, not all the terminals were crimped tightly.

Randy

[howecnc]

I had to seal the control panel door and around the cabinet to keep coolant out. The coolant was getting in and tripping the 110 plugs.

[Phishaholic]

Randy I'll try the wire thing today, I'm pretty sure it is that or the main control board. I have a good seal around the door to the cabinet. Thanks!

Larry O

[bevinp]

Larry O,
I assume your GFI is tripping only when starting the spindle. I recently experienced that same problem with my older machine with the original VFD.

First clarification from Tormach is that they do not recommend GFI-ing the main power to the mill, only the auxillary power (as Randy said). The non-GFI recommendation comes from the manufacturer of the VFD because the VFD can trip some GFIs depending on their sensitivity.

Since we have 240VAC in Australia, all domestic circuits are required to be GFI-ed. Therefore I needed to do thorough testing (with the help of the UM and Tormach) to identify cause. All the testing was either OK or not conclusive except that disconnecting 202 205 wires from the MCB cured the tripping, which confirmed the MCB needed replacing.

Since you have been using the mill for some time without the GFI tripping, I would say that your problem is not a sensitive GFI. And if you are able to use non-GFI power to the mill, Tormach said a faulty MCB is likely to blow the fuse (presumably on the MCB).

I chose to upgrade the VFD which requires a new MCB, but with the discount on returning the old MCB, the net cost is worth the value of the new VFD. For me, its wide speed range in each belt position reduces the amount of belt changing, and others praise its torque. Certainly it has impressive braking (just like the big CNCs!!!).

The non-GFI recommendation applies to the new VFD as well, but your GFI wasn't tripping before so hopefully it wouldn't with the new VFD.

If you do go the upgrade path, just be gentle inserting the four hexagonal brass standoffs under the new VFD; they shear very easily. But don't worry I found that only three hold the board nicely.
Bevin

[68rustang]

Check the cutout in the bottom of the control panel where the parrallel port board is. If the port is touching the edge of the enclosure it can cause problems.