[1000ee-monarch]

Trying to diagnose a noise problem on a machine with an A06B-6052-H002 spindle drive and A06B-1003-B100-R motor. Motor sounds rough, worse at higher speeds. Spindle belt removed.

Disconnecting CN2 while motor was running, putting the motor into a coast, eliminated all noise. So thinking not bearing noise.

Put scope on PA and PB at the drive (A16B-1100-0080 top board), verified against the maintenance manual. Adjusted magnetic pickup till signals look good, no difference in the sound of the motor.

Any ideas what to do next? The maintenance manual I'm looking at does not mention any potentiometer adjustments to deal with noise (gain adjustment, etc.). As a matter of fact it doesn't provide info on a lot of the pots.

One more thing, motor Megs 1.5 Meg so there a chance it's got winding problems. Lead to lead is pretty consistant 0.34 ohm.

Thanks!
Alex

[1000ee-monarch]

Just checked the square wave at PSA and PSB (CH7, CH8). Duty cycle was 50%, but amplitude and offset a bit off. Screen shots of scope and proper waveform from the manual below.....

No mention in the manual how to change amplitude and offset....

Thanks,
Alex.

[guhl]

What about load meter readings?

[1000ee-monarch]

Load meter was reading higher than normal....

Here's an update. We tried running the machine making parts, and it faulted with a DC bus overcurrent...Reset, 5 minutes later same thing. Power off and on did not help this time, DC bus overcurent alarm instantly when trying to run the spindle after that. The drive has officially been killed!

Drive now has a blown output transistor module and probably other damage. Megged motor again, readings vary between 0.5MegOhm and 2MegOhm. Lead-to-lead is still 0.3 ohm. Opened junction box on the motor, smells burned.

It appears that the motor was the reason the spindle drive blew. Lesson learned: when you suspect trouble and the motor megs low, don't keep running it! That 6052 drive is fragile and expensive to repair or replace! Good thing this "customer" is very understanding...

Current plan is to try running this machine with a Yaskawa V1000 variable frequency drive in open-loop vector mode. Drive will be a 10hp unit with a 40A peak output. Orientation is not needed, so that simplifies things.

Since the motor is probably damaged, opening it up and investigating is a good idea.... Updates to follow, the Yaskawa VFD should show up in the mail this week.

Moderators, please feel free to move this thread to a more appropriate section.... I have a feeling this isn't really the correct place as it's under "Machine Controllers Software and Solutions" and this is very much a hardware problem. Thanks!

Alex.

[xjdubber]

Its odd that your megohm reading is varying that much, however at the 1.5 meghohms you mentioned first I personally would have kept running that motor. The rumbling is likely from a bad power module in the drive and it being unable to generate a good three phase sine wave. Which would have heated up the motor quite a bit, meg it again after cooling down, you might see a stable reading. The motor was likely never the problem.

[1000ee-monarch]

The varying megger readings cover multiple tests, using different voltages (250Vdc, 500Vdc, and I did try 1000Vdc once, briefly), over a few days. Also, the reading tends to slowly drift upwards if I maintain the voltage over a few minutes... That's not uncommon.

I normally start megger testing at 250Vdc and if I don't see signs of "breakdown", that is the reading floating around followed by a sharp decline, try at 500Vdc. The readings I got were never steady but did not have the sharp downturn that indicates something arcing over to ground. Even at 1000Vdc over 30 seconds there was no sharp decline in the reading.

I really wish this motor would have either read higher or lower to begin with, making it easier to call it "good" or "bad"... But the ones in the middle are more fun!

[ies fixs]

Alex,

That's a shame the motor is damaged. We see things like that happen all the time here. Do you want it rebuilt or replaced? We can probably fix your drive as well. That will save you a lot of money compared to replacing it. Give me a call or PM me if you're interested. Hope everything turns our well!

Tyler