PARTNER 7 DRIVE PROBLEMS

[scorchtool]

WELL IT STARTED WITH AN AXIS' SERVOMOTOR OSCILLATING RAPIDLY.I FOUND DAMAGED TRANSISTORS ON THE SERVO AMPLIFIER, SO THIS WAS REPLACED WITH NEW AND ALSO REPLACED CABLING WITH NEW AT SAME TIME.TWO OR THREE DAYS LATER A REPEATING ISSUE DEVELOPED WITH THE SAME AXIS, THE ENCODER WAS REPLACED AT THAT TIME BUT NO FIX.THE ACROLOOP BOARD FOR THIS AXIS WAS SENT TO MILLTRONICS FOR EVAL. AND WAS SENT BACK TO US AND PLACED BACK INTO MACHINE BUT REPEATING PROBLEM WAS STILL EVIDENT.NEXT A NEW SERVOMOTOR WAS INSTALLED AND A NEW SET OF PROBLEMS DEVOLOPED.WHEN AN INPUT SIGNAL FOR A COMMAND MOVE IS GIVEN THE SERVOMOTOR TAKES OFF THUS CAUSEING AN EXCESS FOLLOWING ERROR, REPEATED ATTEMPTS TO DIAL IN THE SERVO AMPLIFIER HAVE FAILED.I'VE ALSO SWAPPED AROUND A KNOWN GOOD SERVO AMPLIFIER( WITHOUT CHANGING ANY OF THE BOARD POTS.) TO DRIVE MY PROBLEM AXIS AND ALL I GET IS A SERVOMOTOR THAT RUNS AWAY.
IN REFERENCE TO THE REPEATING PROBLEM, A CONTROLLED MOVE FROM POINT A TO POINT B THEN BACK TO POINT A THUS INCREASES BY .001" EXPONENTIALLY.

[70cyclone]

is it possible the servo motor was not wired correctly relative to the encoder?...that can cause run away problems(the motor is turning the other way compared to what the encoder thinks it should be)
in regards to the repeating problem, have the parameters been lost or messed with? just a couple thoughts....

[smts]

Do this motor have a tach?, encoder or both? The relationship between the tach and the motor is critical to the proper operation of the motor. Try swapping motor leads, and or tach leads and see if that fixes the stability problem...

[scorchtool]

We are going to have the servo amplifier retuned to Glentek's specs., by use of an o-scope.Then we will see if the new servomotor remedied the repeating issue.Yes we have tryed swapping around the armature and tach leads.

[smts]

ok well good luck still sounds like a connection problem

[70cyclone]

Originally Posted by smts ok well good luck still sounds like a connection problem

agreed...for the run away problem...swap those tach wires

[smts]

I have found too that replacing the tach wires, just run them out side the conduit for a test can help too. Also cleaning the tach armature can help too.

Good luck

[scorchtool]

Well once we got the tachometer voltage waveform critically dampened, we now have a smooth running servomotor.

[scorchtool]

Repeating issue was caused by too much noise on the tach. and encoder lines.

Solved

[smts]

congrats, now go make some parts good job !!!!