M5 Mazak, 28 F Emergency Stop Alarm in reverse

Help Tearing my hair out.

My repairman says I have a contactor problem in my M5 Mazak Spindle Controller.

I can manually run the spindle in forward and at low speed and it is smooth. As I increase the speed it makes a racket like the motor is having a hard time running, and at about 450 to 500 rpm it gives me Alarms, 28 F EMERGENCY STOP, 51 THERMAL TRIP, 55 MOTOR OVERLOAD.

When I put it in reverse at zero rpm it is fine until I turn the spindle on then the same alarms.

I have disassembled the SA80 motor contactor cleaned and polished the contacts it made a little difference, the contacts were a little arced but cleaned up nice.

When I removed and checked the relay that controls the contactor field voltage it didn't work at first but when I wiggled it the motor worked intermittently and after cleaning the pins it worked a little smoother at first.

After I monkeyed with it and disassemble it and cleaned and sanded those contacts it did affect it but not fix it but as I moved it it affected the motor. I am going to interchange it for another relay on another machine tomorrow.

The vibration is only in the spindle motor intermittently when the spindle load meter oscillates up. The brushes are fine. The Tach brushes are fine. withe the belts removed everything turned smoothly.

Any ideas? I am not a guru and have no oscilloscope, tachometer or special equipment just a meter.

Can you swap the fwd and rev contactors?

It helps to know what the spindle controller really is.

Could be a bad or out of adjustment encoder.

Try running the spindle in open loop. This can be done up to 500 RPM without a problem.

There should be a parameter for this but which one depends on which drive configuration is in your machine. You may need to contact Mitsubishi for guidance.

I believe he will have a Fanuc control on that old girl.

Big difference between a Mitsubishi drive and motor and a Fanuc drive and motor.

It is a Mitsubishi DL-SCZ-22K. Where are the forward and reverse contacts?

Where are they located, I cleaned the main contactors in the spindle control

Mitsubishi

At 500 RPM it alarms

Did Mazak tech put it in open loop and test it? Contact Mits and get procedure for checking the components of that drive.

If it is plg (encoder on motor) that is causing issue it can be tuned with a DMM since it is 3v peak-peak

It is a Mitsubishi DL-SCZ-22K.

Been a while since I worked on one of those.

Follow the attached troubleshooting guide as best as you can to narrow down the issue, most of the tests only require a meter.

Never mind can't attach. Send me a PM with your email and I will send the guide.

This is a very old DC system, ignore any posts mentioning a PLG in the motor, encoder, or running in open loop. These are for newer AC motors.

Here are a few things to check.

1. On the back of the swing door on the DL-SCZ-22K there is a set of 6 LED's. When running in forward, every other one is lit, 3 in all. When running in reverse the other 3 are lit. If any of the 3 are not lit the same as the others, the logic on the hinge is not firing an SCR properly. Does the pattern change when not running correctly?

2. Pull the dust cover over the motor brushes, and watch for a VERY bright flash of light when the motor alarms out at the 500 or so RPM. The motor may stop with a loud thump in the process.

3. Try running the motor at 10 RPM or as slow as you can. Does it turn smoothly, or a bit jumpy? Is it the same in both directions?

4. Is the phase sequence light lit?


5. What alarm LED's are lit on the DL-SCZ when it alarms out?

PM me an email and I will send more pictures that I can't upload.

Bill

It would be helpful to post pictures of the relays/contactors you are sanding/fileing/wiggling to understand what you are doing. By not understanding the nature of the problem, you can easily be causing additional problems.

Starting a thread with the problem you are having, with only the information you have given, you will not get very good advice.(three posts are about much newer AC drives)

You may be in a position that causes extreme damage to the motor if you continue to try "to make it run" without observing and reporting the symptoms that it gives you. I am expecting that the flash with test #2 could be golf ball sized to filling the entire commutator/ brush area with a ball of very hot, bright fire that causes a bit of damage to commutator, brush holders and wiring in the area every time it happens. If you were able to get the motor up to full speed, and it flashes, you would have to sit down for a half hour or so before you could see again, it is that bright and very hot.

A bit of history on the machine is very helpful too, along with vintage and the control model. I have seen Fanuc 2000's, 5T, 6T and 0T controls on these machines.

Upon inspection using the manual that someone here provided me I went to the tach generator to check the brushes and maybe pull it apart and clean the rotor. As I was doing it I noticed that the flexible connector between the rotor and the motor was broken. I got a funny feeling that this may be my problem lol. So simple. I have a similar M4 that I am selling that I am going to pull that connector off of and check it out. Either way I need a new one and then I will know if that was it for sure. I am pretty sure it is, because going in one direction it runs rough at a higher speed and when it goes into reverse it gives me the 51 tach loss alarm. Makes perfect sense, I will update when I get the absolute on it.

While you are into the tach, check the output when it is back running at very slow speed.
The motor should be quite smooth running in both directions. If not, try the tach from the M4.

These tachs do have a problem with the wires breaking off where they solder to the commutator, giving unstable operation at all speeds.

If you do pull it apart, scribe a line so you can maintain the same rotational relationship between the stator (magnets) and the endbell with the brushes. Otherwise the output is not the same in both directions.

The brushes should go into the same holder they came out of and in the same orientation and not flipped over. They may not seat properly if this is not maintained and give irratic output.

Bill

As a PS it is interesting that in post #1 51 is listed as thermal trip and on the previous post it is listed as a tach loss.