Wire spool motor access 290/310/510 Charmilles

[rock]

We have a 2002 Charmilles 290P with console 2

While facing the front of the machine, above the wire spool at the top left there is a pulley set and belt that unspools the wire. The top left belt pulley is driven from behind by a small motor. Normal operation would be for that motor to start when the wire feed is turned on, also when the tension pulley arm is raised past horizontal that motor should start unspooling wire.

Right now my motor is intermittent, most times it starts but sometimes it doesn't. When it fails to start it will either break the wire or the wire will be pulled through by the lower rollers and the tension arm will raise to maximum allowable height due to excess tension because the unspooling motor is not running.

No error codes accompany this leading me to suspect that the control is sending the signal and assumes the motor is on.

If I rotate the larger pulley on that belt loop by hand during the malfunction the motor will immediately start and continue.

If my diagnosis is correct the control signal and associated outputs along with any relays or contactor is happening as designed and I have a problem with the armature brushes in the motor or some other problem in the motor such as brush residue buildup or possibly an open winding.

The question I have is how best to access this motor for test, cleaning, replacement. I can see it from the side with the velcro bellows retracted but I am looking for the recommended service procedure GFAC would possibly use to remove the motor and it is not in my manual set.

Anybody have any info on getting there in a 290/310/510

 

[WireEDMServices]

I agree that the brushes are the culprit. I usually remove the entire front panel that houses the unspooling motor, encoder arm and brake pulleys so that I can check other components while I'm at it, but you can access the brushes from the bellows or from the rear of the machine if you jog Y+ all the way back. Motor brushes are held in with rubber boots and the tach brushes are held in with a small phillips head.

 

[rock]

I believe even with the longer disassemble time of removing the white plastic panel with all components attached it would be easier to access it. Looking at that panel its 6 screws from the front. A wire connection and a ground? From the open side, and from the control side I see a shaft coupler going to the brake?

Any other stuff to release before the 6 screws to remove it?

 

[WireEDMServices]

It's been a little while, but from the open side, I believe you have 1 large connector, a single wire connector, and a coax going to the level arm encoder. The control side just has the flex coupler going to the brake.

 

[rock]

I will get in there maybe this weekend thanks for you help

 

[rock]

Got a chance to work on the wire unspool motor this evening. The only things to disconnect before pulling the white panel was the wire connector and single wire on the side door side and the brake shaft coupling.

Steps
Move both axis to front left corner x-&y-

Power off, lock out

Remove transparent wire spool cover, wire spool, aluminum tube, bottom slide out plastic piece around aluminum tube.

Unplug coiled wires going to electrodes used for stretching wire for manual threading.

Remove transparent guard housing 6 screws on bottom and 2 in upper corners.
The bottom screws go into inserts in the plastic and the inserts may be sticking in the holes preventing bottom from pulling out. I had to loosen the screws and lightly knock the screw heads to fully seat the inserts and get them to clear the stainless flange.

Remove left side door.

Unfasten 4 velcro strips holding bellows all around on the rear of the housing.

On the control side unscrew the 2 brake coupling screws on the front end. Verify coupling is loose by rotating.

On the opposite side unplug the black wire connector and the single wire.

Front white panel is ready to remove with all components, not too heavy, maybe 25-30 lbs.

Important! Before releasing the 6 screws holding the big white panel place a 5mm shim between the white panel and the bottom stainless flange so you dont stress the brake flex coupling by letting the white panel slide down.

Remove the 6 screws and washers holding panel. Carefully pull the panel out taking care for the flex coupling.

I set it down on a office chair.

My issue was intermittent wire spool motor fail to start.

Removed wires from brush terminals. Removed rubber brush bushings with large flat screwdriver as a prybar. These were stiff from age but came free easily.

Pulled brushes out, about 8mm left on length, so ok life left.

Blew out big old dust cloud from motor with air hose. Worn brush dust. Cleaned brush sockets with small pipe cleaner.

Re installed brushes and rubber holder plugs.

Checked commutation resistance with ohm meter across brush terminals. No dead windings. Consistently 1.3 ohms per winding when rotating stopping rotating to each set.

Cleaned it some and reassembled going steps in reverse. Its all good now, motor is working properly.

 

[WireEDMServices]

Awesome! Get some spare brushes and brush holders from Novotec. When going through so much trouble to get to the brushes, I like to go ahead and replace with new. That way it should be a good long while before having to do it again.