Project Description

Pacific-Scientific Servo Motor Repair

Servotech refurbishes many different manufacturers of servo motors. Pacific-Scientific servo motors are no exception. Each motor at our facility is subjected to an intense evaluation to determine the cause of failure. More than just a hunt for major issues, the evaluation process is a comprehensive look at all aspects of the servo motor both physical and electronic. Fixing problems is a good start but is not all there is to refurbishment. Our refurbishment process brings old worn down Pacific-Scientific servo motors back up to the quality condition they were in when the factory produced them new.

It is important to our company, to produce motors that meet or surpass factory standards. In order to accomplish this, we need factory information and original technical data sheets. Unquestioningly, the best way to obtain this information is through a healthy and working relationship with the motor manufacturer. Without Pacific-Scientific information, a motor can only be repaired to “running” condition. We need to be sure your motor will perform in your machine at the tolerances and conditions it was designed for.

Our goal is to give you a servo motor that is not only repaired but has been refurbished back to as new condition. Our repair procedure often follows these steps:

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1. Evaluation of Your Pac-Sci Servo Motor

Pacific-Scientific evaluation consists of an inspection of all mechanical parts, as well as a test process that determines the electrical integrity of the motor, and the viability of the feedback. Some aspects of the evaluation include checks on/for:

  • Bearing fits
  • Housing fits
  • Worn output shafts
  • Connector condition
  • Worn output shafts
  • Corroded and/or broken flanges
  • Resolver and wiring state
Pacific-Scientific Servo Motor for RepairRepaired Pacific-Scientific Servo Motor
A typical Pacific-Scientific when it arrives in the shop, and then after we service it.

2. Servo Motor Repair

Any problems found during our evaluation get fixed. Broken parts are either re-manufactured repaired or replaced. Anything that is not broken but does not meet factory specification, is also addressed. Often we:

  • Adjust pre-load on bearings for optimum life.
  • Re-manufacture a new Pacific-Scientific servo motor front flange using the old flange and factory dimensions.
  • Replace older style connectors with military spec. connectors.
  • Repair all the windings. Both AC and DC servo motors windings are washed, baked and tested.
  • Repair or replace brush holders and Bake-O-Lite insulation tubes on DC motors.
Worn Pac-Sci Servo Motor ConnectorsNew Pac-Sci Servo Motor Connectors
Left: An initial Pacific-Scientific resolver with bad output. Right: New resolver installed on a Pacific-Scientific servo motor with a proper alignment.

3. Preliminary Testing on Pac-Sci Factory Drives

Throughout the assembly process each Pacific-Scientific servo motor repair is meggered many times. Some of our other tests include:

  • Test to confirm there are no grounded electrical parts in the servo motor.
  • Test holding brake pick voltage, and coil resistance.
  • All AC stators are surge tested to at least 1500 volts.
  • After the baking process DC Servo motor armatures go through a bar to bar test. This test will show if there are any shorts or opens in the winding.
  • Servo motor alignment.

4. Servo Motor Assembly

The next step for your Pacific-Scientific motor is reassembly. Our process seeks to improve components and the performance characteristics of the motors. We incorporate the following:

  • High-grade sealed bearings – we feel that each Pacific-Scientific servo motor repair will have a longer life with sealed bearings. Seals protect the bearings from harmful dirt and contamination that can easily penetrate the metal shielded bearings.
  • Double lip seals in the front flange – these seals keep coolant from getting at the bearings and the windings.
  • All new seals, O-rings, gaskets and connectors – ensure that your Pacific-Scientific servo motor is protected from liquid contamination. If the sealing strategy of the motor is deemed inadequate for the operating conditions we will employ a gasket eliminator or epoxy between motor sealing surfaces.
  • Two-part epoxy coating for an added protection – the same coating used on Navy submarines.
Bad Pacific-Scientific Servo Motor ResolverNew Pacific-Scientific Servo Motor Resolver
Servotech replaces worn and old connectors with the upgraded military spec. connectors which last longer than standard connectors and are sealed against contamination.

5. Final Motor Testing

The conclusion of the Pacific-Scientific servo motor repair process is to run the motor on a Pacific-Scientific drive just like the one in your machine. There is a lot of merit to testing the individual components of a motor, but the entire process culminates by running the motor on a factory drive.

Our Final Test Department, will run the motor up to the maximum rated speeds and electrical loads. We also frequently update our final test capabilities by purchasing new drives. It is important to