How to Repair an Industrial AC Servo Motor

Repair Zone’s procedures require all major electrical and mechanical components making up the servo motor are independently tested upon motor disassembly.  Your servo motor will go through the following intensive repair process:

1. We first run a “Meg test” to check and see if any moisture potentially grounded motor.  If moisture has compromised the stator, the motor is disassembled and the windings are washed and baked.  Afterwards, the unit is Meg tested again.

   Step 1: Meg Test the Servo Motor   Step 2: Meg Test again after Moisture is Removed

Detailed Mechanical Tolerance Check

2. We check the bearings, housing, and end bells for wear and/or damage.

3. We check the bearing seats to ensure that they within correct tolerance.  Also, we look over the shaft to verify straightness and the condition of the shaft extension.  If anything is worn or out of spec we machine it to proper specs.

Step 3: The servo motor is disassembled   Step 4: Inspect the disassembled servo motor

 In-house Machining Center

5. We check connectors, encoder covers, release voltage, and independent torque testing of all brake assemblies.

6. We check to verify that each feedback device – encoder, resolver, hall sensor, tachometer – to make sure they are counting/functioning properly. If bad, we either repair or replace the part.

Step 5 servo motor repair   Step 6 servo motor repair

In-house Winding Department

7. We do a “Back EMF” test; this checks the magnetic strength of the rotor.

8. We “Surge Test” the stator and do a complete electrical winding evaluation to verify the quality of the winding; if the stator fails we rewind it, in-house.  Then we dip it in epoxy resin and bake it to set the finish on the windings.

9. We replace all bearings with high grade shielded bearings for long life and performance.

10. We replace all seals, O-rings, connectors, and any necessary worn or damaged part.

Step 7 servo motor repair   Step 8 servo motor repair

11. Reassemble and align the motor back to manufacture specs.

Step 9 servo motor repair   Step 10 servo motor repair

12. After all necessary repairs are performed; the motor is run tested with a manufacturers drive and complete servo system to simulate your machine, for data (e.g. amp, voltage, RPM).   Load testing is optional and performed to match the manufacturer’s torque/speed curve at a minimum of 3 different run speeds.

13. Buff and paint the motor and create new nameplates when needed.  Our custom foam packaging system protects the motor in transit and returns to your facility in a ‘new in box’ state.

Step 11 servo motor repair   Step 12 servo motor repair

Ready to send your ill-working servo motor in for repair? Request a quote or send your motor in for a thorough inspection, exact quote, and repair. We repair Allen Bradley, Fanuc, Indramat, Modicon, and more manufacturer branded servo motors.

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