Need help with strange Fadal problems

Last week I went to fire one of the Fadals up, and when I went to zero it, the rotary axis faulted out.
Tried resetting, checked all fuses, etc... couldnt find anything wrong.
Assumed the cable or motor went for a dump, had work to do on it. So I disconnected the 4th and put the plug in.
Machine would then power up and home, got parts made.

Was running some very light aluminum work in it last Thursday, no problems.
Friday morning I go to power it up, and I hear what sounded like a bug zapper at the top of the machine (at power on, not even homing yet).
Smoke coming from the Z axis motor connector... SOB, quick shut it down.

Climb up, and disconnect the motor connector (power, not resolver) to inspect... the pins are burned off the motor, and the plug end of the cable is just carbon now.
So ok, I dont have time to piss around with that... work to do. But Ive got 15 tools in the machine.

Fire the machine up with the motor plug disconnected, and as soon as I threw the disconnect the freaking plug arced to itself!


Now, Ive worked around machine tools, automation, and all kinds of equipment for a lot of years.... and Ive never seen that on a servo motor, never mind the lead self arcing.

Is losing the 4th, and then the Z motor\connector leads burning up connected, and what should I try to troubleshoot before throwing parts at this bloody thing?
I do have another fadal I can swap parts for troubleshooting, but Id rather not burn them up and not be able to make parts on my good machine.

Could be a strange coincidence, but I’d start by checking the incoming power and the 110v leaving the transformer, before you even hit the green button.


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plug arced to itself = an carbon arc
Probably there was an short in the motor, plug, or wiring, and when the current passed thru the plug it left the carbon trace.
Meg the motor and harness before powering up again.

I think you are going to have to replace the cable. Insulation on each wire has melted off and bare wires are touching each other. BTDT Got the T shirt.

Ill check out the cable with the meter.
Much rather check out the connector (they want 600 usd for the frigging cable)
Power to machine is excellent RPC through isolation TX and through a secondary tx. Better than grid.

Frankly, im surprised that a connection out of the mist n chit could go poof. Burned connection poles off the motor connector.
Axis moves free....

Wanted to provide an update.

Local rebuilder wanted 2K Canadian microbucks to rebuild the motor.
Got a new cable and motor from Idaho for just under a grand (rebuilt, but with 2 year warrantee).

Wired up and good to go.
Im going to pull the old motor apart and see what I can find, cable checked out OK, but the connector was cooked off.

I did notice the axis load was hanging at 35% with the next motor installed, and the Z parked at toolchange height.
Backed off the straps a wee bit (had adjusted them 6 months ago due to drill wander), and oiled the snot out of the z ways and screw.

I have a feeling i need to redo the Z lube system. Previous owner was using some stinky sulphur cheap crap waylube.