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Spindle Servo Motor Repair


Spindle Motor Repair

Spindles endure an intense evaluation specifically tailored to their characteristics. We obtain a comprehensive understanding of the spindle motor’s condition not only to fix what is broken, but also to fine tune the motor for optimum performance. It is our goal to retrofit, repair, or re-manufacture your spindle motor back to “Like New” condition.

Proper spindle motor repair requires specialized knowledge, skills and tooling. It is important for any company that repairs spindle motors to have precision measuring devices to check mechanical tolerances, balance, and feedback signal integrity. Servotech has built relationships with many manufacturers such as Mitsubishi, Yaskawa, Fagor, and Fanuc. These relationships have allowed us to build a vast library of documentation, which we utilize to verify the quality of our repairs.

Servo Motor Down?
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Call 866-807-3786 for technical support or 

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Spindle Motor Manufacturers We Repair

Allen-Bradley (AB) Getty’s Moog
Baldor GMN Okuma
CEG Haas Perske
Cincinnati Milacron HSD PSD Colombo
Fanuc Indramat Siemens
Fischer Komo SKF
Fuji Mitsubishi Yaskawa

1. Spindle Motor Evaluation

Servotech stringently inspects all electrical and mechanical parts on all spindle motors. During our evaluation, we check for:

  • Bearing fits and bearing journals on the rotor
  • End-bell cooling jacket integrity
  • Flange fits, and mounting surface imperfections
  • Broken conduit boxes, compromised terminal blocks
  • Worn output shafts, key ways, and pulleys
  • Corroded and/or broken flanges
  • Flanges suffering from stress fractures
  • Winding condition
  • Cooling fan condition
Spindle Servo Rotor Needing RepairRepair Spindle Servo Motor Balance
Inspection of a spindle rotor with a bad bearing journal, and initial balance reading on a rotor.

2. Repair of Motor Problems

Any defective parts that do not meet factory standards are repaired during the process. Some of our standard procedures include:

  • Windings – AC and DC spindle windings are washed, baked, and redundantly tested.
  • Re-winding – any windings that are shorted or irreparably contaminated are stripped and rewound in our professional winding department.
  • Bearing fits that do not meet tolerances are bored and bushed. Bearing journals are chromed and ground.
  • Rotors are balanced by our balancing department specialists to decrease vibration.
  • Cooling fans are rebuilt or replaced depending on their condition and availability. Siemens and Mitsubishi spindle motors use a standard cooling fan that is not cost effective to rebuild so Servotech keeps plenty of them in stock.
Repair of Servo MotorSpindle Servo Motor Repair
Servotech stock magnetic proximity sensor and its output, used by many different manufacturers. Pictured: Fanuc

3. Preliminary Testing of Repaired Spindle Motor

Each spindle motor repair will be meggered numerous times. Both electrical and mechanical procedures constitute our battery of tests.

  • “Spindle-scope”, an iPad friendly vibration analysis test to identify excessive vibration.
  • Test to confirm there are no grounded electrical parts in the spindle motor (Megger test).
  • All AC stators are surge tested to at least 1500 volts.
  • After the baking process DC armatures go through a bar to bar test. This test will show if there are any shorts or opens in the winding.
  • Spindle sensor testing and adjustment. Spindles often utilize proximity sensors that need to be tuned or gapped to very tight tolerances. Fanuc for example uses toothed wheels that need to be gapped just right in order to achieve the proper voltages that the drive will recognize without errors.
Servo Motor Repair TestingSpindle Servo Motor Repairs
A spindle during the repair process with a fan that needs rebuilding, and the final product. Mitsubishi spindle motor.

4. Spindle Assembly

Once the individual components of a spindle have been repaired and tested to our technician’s satisfaction, the motors are rebuilt. The assembly process employs careful handling of delicate parts and often improves internal motor components. Our assembled spindle motors utilize:

  • High-speed ceramic bearings – any application that sees high RPM, 8000 or greater, is subject to tremendous forces that can take small imperfections and magnify them. Our bearing choice is as important as our machining skill.
  • High speed grease- complimentary to the bearings is good grease, no component of our spindle motors is skimped on. It does not behoove our process or our customers to cut corners, our collection of high speed grease is no exception.
  • All new seals, O-rings, gaskets and connectors – ensure that your spindle motor is protected from liquid contamination.
  • Two-part epoxy coating for an added protection – the same coating used on Navy submarines.
Spindle Servo Motor RepairsSpindle Servo Motor Repair
Spindle motor being run on a factory drive in the final test department, accompanied by a vibration analysis report that was preformed simultaneously.

5. Final Spindle Motor Testing

Once the spindle motor has been re-assembled, it is subjected to final testing. Final testing is its own department at Servotech that re-tests every component of the motor, cooling fan and sensor. The spindle motor is then run on a factory drive. Bearings are worn in properly before the motor is brought up to full RPM. Once the motor has achieved maximum rpm, final vibration analysis is conducted to make sure that the motor will not wear through its components in undo time. Servotech takes pride in the spindle drives it has accrued.

Mitsubishi spindle motors were designed to run on Mitsubishi drives, the same can be said for Fanuc and Yaskawa. Our drive collection is constantly being upgraded and added to, in an effort to stay on top of current technology and to give our final test department the edge it needs to ensure that the repair process was completed correctly.

6. Final Name Plating

Before leaving the shop, Servotech fabricates all new nameplates. Each nameplate is completed with factory data so that the appropriate information is available to the customer when they need it to install their spindle motor. Additionally, we include the Servotech job number that corresponds to the motor paperwork so the repair can be traced and quickly referenced for data and procedures that were conducted.

Authorized Yaskawa Servo Repair


Authorized Yaskawa Servo Motor Repair Facility

Servotech specializes in the repair of Yaskawa servo motors. We are in direct communication with Yaskawa, and are authorized to purchase Yaskawa parts to aid in the refurbishment of their servomotors.

Yaskawa servo motors are complex, precise and delicate. Very often the feedback devices can see failures only diagnosable with the proper Yaskawa drives and equipment. Direct communication with Yaskawa allows us to obtain the proper servo motor encoders for each and every Yaskawa servo motor repair that enters our shop.

Servo Motor Repair Company

Servo Motor Down?
Get Immediate Assistance.

Call 866-807-3786 for technical support or 

Click to request a quote

Repair & Refurbishment of Yaskawa Servo Motors

Servotech has extensive experience with Yaskawa servo motor repair. Yaskawa is one of the largest automation manufacturers in the world, and produces high-end servo motors and spindle motors. Servotech specializes in the repair of Yaskawa motors, from Hicup low inertia DC brush type servo motors, to AC brushless servo motors with absolute encoders, to the new series Yaskawa servo motors with 19 Bit serialized encoders. Servotech’s servo motor expertise, coupled with our ability to purchase parts directly from Yaskawa, allows us to provide some of the industry’s best Yaskawa servo motor repair services.

More on our Yaskawa Servo Motor Repair Process.

Yaskawa servo motor: afterNew Yaskawa servo motor name plate