[NationalAutomat]

I have an arrow 750 with a z axis that went into foldback on machine alignment. I replaced the servo with a used one from ebay and get the same result. The screw is not in a bind. There are no other error lights occurring on the drive. When I try to jog the axis the servo makes a whining sound for a couple of seconds and then the error shuts down machine power. There is no movement.

[mike_Kilroy]

whine sounds like very hii current flowing. then it would have to go into foldback to reduced current to protect stuff...

so you replaced "servo?" what is that? motor? drive? which one? tell me so I dont have to write 2x as much stuff...

[mike_Kilroy]

so, I am shutini down computer so will write extra anyway.

you need to remove the 3 motor leads Ma,Mb,Mc from drive and power up. if still squeel and foldback, the DRIVE is shorted inside. no fault? power down, put cable back on drive, unplug other end - power ms connector on motor. repeat. if fault, yor cable has a phase to phase short in it. no fault? then your motor is shorted out inside.

doing this tsting, do not remove the feedback cable off system. just power cable. let us know.

[NationalAutomat]

All of this started when the roof gave way during a storm a few weeks ago. The z motor took on water because the cover had gotten lost. I did not know it had water in it when I started the machine. Drive went into foldback. After I had figured out what was happening I removed it from service and purchased a replacement motor. I installed it today. Same thing is happening with the foldback. I had considered that the brake isn't releasing but I do not the details of the circuit. The brake makes a small noise but it does not make the 'chunk' I am used to hearing when the e stop is pushed.

[NationalAutomat]

so, I am shutini down computer so will write extra anyway. you need to remove the 3 motor leads Ma,Mb,Mc from drive and power up. if still squeel and foldback, the DRIVE is shorted inside. no fault? power down, put cable back on drive, unplug other end - power ms connector on motor. repeat. if fault, yor cable has a phase to phase short in it. no fault? then your motor is shorted out inside. doing this tsting, do not remove the feedback cable off system. just power cable. let us know.

Mike, I have done the test this morning. In all 3 scenarios I get: Z axis servo fail The z axis follwing error has exceeded the configured servo fail limit 27.999 Verify axis gains and drive connections. The system no longer makes the whining sound that it was making yesterday. Thanks John

[mike_Kilroy]

Check my last post; you must do those tests to identify which item is the problem. If motor, yes, it could be the brake not releasing. you will need to check that it is getting its voltage to turn on. perhaps remove motor from screw so you can turn it by hand? What motor and drive do you have? blue or black drives?

[NationalAutomat]

I did the tests as described below. The motor is black and I can turn the screw by hand. The voltage from plug 33 going to the electromagnet in the brake is getting 97vac. The control transformer is making 110vac.

Motor
CINCINNATI MILACRON GOLDLINE BRUSHLESS SERVO MOTOR 1-604-0222 95H414W-402

I have done the test this morning. In all 3 scenarios I get: Z axis servo fail The z axis follwing error has exceeded the configured servo fail limit 27.999 Verify axis gains and drive connections. The system no longer makes the whining sound that it was making yesterday. Thanks John

[mike_Kilroy]

Nice talking to you on phone John. Yes, if you end all items we will test them and find the bad item for you. I suspect we will find the drive shorted internally from the wet motor being sorta shorted out when powered up after the storm. So you ended up with a shorted drive, you replaced the motor and still have the overcurrent fault (because the damage actually happened in the old drive from the wet motor). Your wet motor may have dried by now and may be ok again? But we will test that theory.

Yor brake voltages are perfect.

[NationalAutomat]

Thank you.