Everything was great until it wasn't <running parts now>

[SlicedBread]

We have a Fryer vertical mill that we installed the Centroid All-in-1 control into. It previously had an Analam control system with Analam DC motors.
We got it up and working and had about two weeks of machining bliss. This week we had a problem were the X motor was unable to move the axis. Our power supply voltage was right on at 165VDC. We have the Amperage DIP switch setting at 9amps for a nameplate rating of 6.5A and our Y and Z motors were still moving well.

We removed the motor and turned the leadscrew by hand to feel the friction. We thought that it moved smoothly, so we dug into the motor. Connections were good to both the the encoder and the motor. The brushes look good with plenty of life left on them and the springs look good. Bearing turned freely. We took the motor further apart but found nothing else wrong. We replaced the screw for the ground wire inside the motor and cleaned up the ground connection, just because we were in there. We cleaned the carbon off the commutator and now have shiny copper. Cleaned the carbon dust inside the motor. We put a little grease on the seals on each end of the motor since the motor hasn't been opened since it was new in 1999. We then put everything back together and started it up. The X is now good. We had to retune the motor since it was somehow way different than before, but it's working.

Now we are getting an error on the Z-Axis. This occured before tuning the X-motor. We didn't touch the Z-axis. We didn't even look up there at are speak the words "Z-axis", but we have a Z-axis error. The message is Full Power without motion. We checked the motor connections and they are good.

What would cause this? Is there a way we can check the motor offline? Is there something we should be looking for? I checked the voltage coming into the All-in-1 for the motors and it is 166 vdc.

[cncsnw]

See Tech Bulletin 155 for motor quick checks. Pay particular attention to the armature-to-chassis resistance.
https://www.centroidcnc.com/dealersuppo ... ds/155.pdf

Without a Report, we cannot see how you have your limits configured. If your limit input numbers on the Machine Configuration -> Motor Parameters are set to zero, but a limit switch is tripped or disconnected, then you will get no movement, and typically a "411 ... full power without motion" stall. If, on the other hand, you have correct input numbers on the Motor Parameters table, then a tripped or disconnected limit will give a "407 ... limit tripped" error.

Test axes using the yellow jog buttons, in Slow, Continuous mode. You do not need to home the machine before jogging. You can test X and Y for movement that way, even if Z does not work.

You can isolate the problem to drive or motor by connecting a known-good motor (e.g. Y) to the Z axis drive output and encoder input. If the Y motor does not move when connected to the Z output, and you do not have a limit switch problem, then you have a drive problem with the Z output.

Check the fuses on the drive. Note, however, that if you have a blown axis fuse on the drive, then you have a serious motor or drive problem that needs to be fixed.

[SlicedBread]

Good ideas. Thanks. We checked the motor and it checked out good. We then connected the Y motor to the Z-Axis output and connected the Z motor to the Y-Axis output and the Z motor is moving good now but the Y motor doesn't move. Then we checked the fuses on the drives and found that the Z axis fuse is blown. We then put a fuse in there and all motors don't move even though all three fuses are good.

I removed the motor connectors at the board and checked the resistance of each motor from the from the positive to the negative. On the Y and Z motors we got around 3 ohms and almost 5 ohms for X. We then went from the motor power wire to the ground wire on each motor, we got infinite on the Y and Z, but got 400 k ohms on the X motor. This seems strange because the X was working good and the Z was the one that blew the fuse.

It looks like we have a problem on the control board. And our motor resistances are not all the same. What is the next step?

[SlicedBread]

Ahhh, so there was nothing wrong with the X-motor in the first place, it was simply because we must have blown something on the board that all drives didn't work. But then we got X and Y to work, I would guess by that point the fuse had blown on the Z allowing those axis to work, but we got the error on the Z which was the problem. Is that correct?

Well, we still need to get this working. What can we do?

[centroid467]

If the Z axis fuse blew and the drive does not work after replacing said fuse, it is very likely that the board needs repair. I recommend contacting support for an RMA and sending in the ALLIN1DC. This kind of repair is typically pretty quick but I can only speculate about what caused the other axes to stop moving after you replaced the blown Z fuse.

[cncsnw]

If the X motor has only 400K resistance from armature to ground, you should address that as well (e.g. by replacing the motor and/or having the old one refurbished). Even if that did not trigger the current problem, it is going to cause problems in the near future.

[SlicedBread]

Thanks. We will check the Z motor and get an RMA going. Thank you for the quick replies and the help.

[SlicedBread]

The Z motor checked out perfect. The X motor has low resistance, under 1000 ohms, from the motor wires to ground, but we had no problem on the X-drive. I rebuilt the motor paying special attention to the brush holders, because this is where I was seeing that low resistance. The brush holders were pushed out of the motor body and cleaned up with Scotchbrite on the lathe. Everything inside was cleaned. The commutator was cleaned with Scotchbrite as well. I am now getting 20 Mega ohms between the black wire and ground and 20 Mega ohms between the red wire and ground. Between the black and red wire I'm getting 3.8 ohms. So, this is ready to go back in the machine. I'll spin the motor a little to let the brushes settle into the commutator better. I'm waiting on the return of the repaired Allin1DC controller.

I'm hoping that somehow the bad motor on the X-Axis somehow affected the drive on Z. Everything else seems to be good.

[SlicedBread]

Coolant had gotten inside this motor housing. The flexible conduit had hardened over the years of use, it looks like from exposure to coolant, and cracked, allowing coolant to enter. The Z motor flexible conduit remains flexible, I believe because it wasn't exposed to coolant.

There was originally an tachometer insided for the Anilam controls. Since it wasn't needed anymore, I removed it.

There did not seem to be any liquid coolant in the part of the motor housing with the brushes and rotor. But I was reading 800 ohms from the motor power wire to the ground. So there was some path to ground that was much lower resistance than it should have been.

Brush holders were removed and cleaned up.

The housing has been cleaned and painted. The brush holders are in place and the wires attached to the brush holders. At this point I was getting infinite ohms from the red or black wires to ground.

We are buttoned up and ready to go again. My concern of course is that the fuse on the Z axis blew, not the X. During the repair they did fid a failure on the "high-side" of the X too. But it remains a mystery why the Z fuse blew. I don't want to go through getting the board repaired again and whatever the next step is going to be for motors. I presume buying a new one.

Fingers crossed. I'll keep you posted.

[cnckeith]

I would not connect this motor up to an all-in-one DC