[RussMachine]

The VFD inside my 770 shut-off, and went completely dark today in mid-cut.
What happened?
I was running a 1/2" Aluminum cutting endmill, 2-flute, at 9000 RPM and 30 IPM, with a .03 DOC.
It was running just fine, plowing along, when it suddenly went quiet.
UH-OH!, broken endmill (My first thought).
I hit Feedhold, and retracted Z.
The spindle was off.
WHATTHEHELL!!???
I tried restarting it with MACH, and No-Go.
So I opened the cabinet, and the VFD was dark.
Hmmmm...
I let it chill for a couple of minutes, then used the Manual 'Spindle On' switch, on the panel.
This woke-up the VFD.
I noticed that the endmill had a chipped flute.
So my questions are.....
Did the chipped endmill cause the spindle motor to overload, and make the VFD shut off?
Did the VFD 'over-torque' and shut-off?
Why did it just shut off like that?
Any ideas?

[mike sr1]

safety switch on spindle door possibly.
was the machine still indicating it was homed? Was the program and steppers still running after the VFD went down?
Loose wire connection somewhere?

The chipped flute may have been done when the spindle stopped.

[SCzEngrgGroup]

I'm really curious about your feeds and speeds, especially at such a tiny DOC - 9000RPM is way too fast for a 1/2" tool, and 30 IPM is WAY too slow. That's a recipe for chip welding and rubbing, both of which drastically reduce tool life.

If the VFD was actually turned off, as in no power, then you need to look at any safety circuits (door interlocks, etc.) capable of turning of power to the VFD. If the VFD itself faulted, it would not power down.

Regards,
Ray L.

[menzzer37]

Check the jumper wire for the VFD. It sounds dumb, but we had an 1100 go down for this reason. Replaced the jumper wire...and back up and running. No idea.

[Don Clement]

I have had this happen with my 1100 due to the door interlock switch opening. That's one issue the PDB helps with because I almost never open the spindle door anymore.

Don Clement

[RussMachine]

Well, I called Tech Support, just out of curiosity.
They said only two things would cause the VFD to shut off.
Spindle door interlock tripped. -Or- The Spindle run key on the front of the panel has loose wires.
I scooted the Spindle door switch closer to the door.
Hopefully that fixes it.

[talonosi]

Well, I called Tech Support, just out of curiosity.
They said only two things would cause the VFD to shut off.
Spindle door interlock tripped. -Or- The Spindle run key on the front of the panel has loose wires.
I scooted the Spindle door switch closer to the door.
Hopefully that fixes it.

Sorry for a revival of an old thread, but this happened to me on my Series 1 PCNC 1100. Did moving the spindle door switch help?

[RussMachine]

YES!
I slid the switch closer to the door, so that the plunger goes 'deeper' into the switch.
It worked! No problems since then.
Wow! April of '14

[talonosi]

I thought I would follow up to let you know my solution. Initially I thought it may be a thermal issue with the VFD since I was operating on 208V and hadn't installed the boost transformer (I'm assuming the machine draws higher amperage at 208v vs 240v). I installed the boost converter and had the same issues. The issues ultimately became more frequent, with the VFD shutting off after just a 1-2 minutes of operation. I ended up tightening up all of the screws on the VFD and control board, they were surprisingly loose which I assume was due to creep/compression of the wire over the last 8 years. Once I had snugged it all up I haven't had any issues at all in about 30 minutes of operation. I did not change the position of the switch (but did pound on the cover while the spindle was on to see if I could get it to trigger, it didn't have any issues).

Thanks for your help!

[Wirecutter]

+1 on the spindle door. I was running a part with lots of (manual) tool changes, and had gotten a little too "familiar" (i.e. quick) with the process of unlatching and latching the door. Lucky for me, I was right there. The machine was doing a fairly slow, straight cut. I heard the spindle unexpectedly start slowing way down, and I slapped the E-stop button and didn't break anything. It took me about 30 minutes of cussing and searching to discover that, in my haste, I'd failed to properly latch the door. Doh!! I'm a lot more careful now.
-Mark