Emergency: same day
For a line-down motor, where the fault and parts allow. WhatsApp us before you send it so the bench is kept free.
Questions answered · Servo motor repair
Servo motor repair questions, answered in plain language
Yes, a servo motor can be repaired, and it will run after repair when the encoder or resolver is aligned and the motor is tested. Here are the common worries answered: myths, alignment, our universal test equipment and how Star Automations differs from a normal repair centre.
By Suresh Sankaran, founder of Star Automations, servo motor repair since 1998.
- 25+years of servo repair, since 2000
- 3,000+customers across India
- 100+servo brands covered by our universal servo motor test equipment
- 5sites: Puducherry, Chennai, Bengaluru, Hyderabad, Delhi
- Same dayemergency repair option*
*Where the fault and parts allow. Every repaired unit returns with a printed test report.
Repair turnaround you can plan around
Send a photo of the nameplate first. We confirm whether the motor is repairable, and the quote, the same working day.
Urgent: 3 working days
Repair, encoder alignment and test, counted from the day the motor reaches the bench and the quote is approved.
Standard: 7 working days
Full repair, encoder alignment, run test under load and a printed test report.
- Free repairability check from a nameplate photo
- Printed test report with every motor
- Written warranty, terms stated on every quotation
- Pickup can be arranged; parts that must be imported are quoted with their own timeline
01Myths
Repair myths and worries
Why do I get a mismatch error after fitting a new servo motor of the same brand and kW?
Because the drive checks more than power. It compares the motor series, encoder type and resolution, motor ID, voltage class and speed with what it is set up for. A motor with the same brand and kW can still belong to a different series or have a different encoder, so the drive refuses to run it. The fix is to match the full model code, set the correct motor parameters and align or program the encoder. Read the full explanation.
Can a servo motor be repaired?
Yes. Most servo motor faults can be repaired: worn bearings, encoder or resolver faults, brake faults, seals, damaged connectors and many winding faults. A motor is replaced only when the damage is beyond repair, such as a cracked housing, a bent shaft or weak magnets. We tell you which it is after inspection, with photos.
Why do people say a servo motor cannot be repaired?
Because many first attempts fail. A general repair shop changes the bearing or rewinds the coil and tests the motor like an ordinary motor. A servo motor also needs its encoder or resolver set exactly against the rotor magnets and proved with a drive. Without the equipment and data for that, the motor does not run and the conclusion becomes "it cannot be repaired". In most such cases the motor was repairable; the last step was missing.
I changed the bearing correctly. Why does the motor not run?
Changing the bearing means the motor and feedback were taken apart. After reassembly the position of the encoder or resolver against the rotor magnets is no longer guaranteed, so the drive cannot tell where the magnets are. The motor then jerks, vibrates, runs the wrong way or trips an alarm. It needs alignment, and sometimes programming. Read the full explanation.
Why does a servo motor need alignment when an ordinary motor does not?
An ordinary motor turns by itself when it gets power. A servo motor turns only when the drive sends current at exactly the right moment for the position of the magnets. The encoder or resolver provides that position, so it must be set correctly. It is like a compass: if it is put back a few degrees off, everything it shows is wrong.
What is the difference between an encoder and a resolver, and what must be done for each?
An encoder is an electronic sensor, either incremental or absolute. It is aligned to the rotor, and serial or absolute types may also need programming and, for multi-turn types, the battery and machine origin set again. A resolver is a simple analog sensor; its stator is turned to the electrical zero against the rotor and locked, and some drives have a resolver offset setting. Details differ by brand and model.
Will the motor run after repair?
Yes. That is why every motor is run on our Universal Servo Motor Repair Equipment before it leaves. It is seen running, under no load and load, and a printed test report goes with it.
My mechanic already opened or tried the motor. Can you still repair it?
In most cases yes. Send it as it is and tell us what was done. We check bearings, magnets, winding and feedback before aligning it.
Is it better to repair a servo motor or buy a new one?
In most cases repair is faster and costs less than a new motor, especially for older or discontinued models. A new motor can also bring a mismatch with the drive and settings. We check the nameplate and tell you honestly whether repair is practical before you courier the motor.
Which servo motor brands does Star Automations repair?
We repair 180+ servo brands on our Universal Servo Motor Repair Equipment, including Mitsubishi, Yaskawa, Fanuc, Siemens, Panasonic, Delta, Allen-Bradley, Omron, Bosch Rexroth, Kollmorgen and Parker. If your brand is not listed, send the nameplate and we confirm.
Which cities do you serve for servo motor repair?
We serve all of India. We have offices in Puducherry, Chennai, Bengaluru, Hyderabad and Delhi, and customers in Mumbai, Pune, Ahmedabad, Kolkata, Coimbatore, Hosur, Gurugram, Noida, Faridabad and other cities send motors by courier. Send the nameplate photo and we confirm repairability and quote before you ship.
Do you have an office in Delhi for servo motor repair?
Yes. Star Automations has an office in New Rajinder Nagar, Delhi. Call the Delhi office on +91 93110 09940 (Hyderabad office: +91 95855 50107) or WhatsApp +91 97866 22233 with the nameplate photo and alarm code, and we guide you on the next step.
What is the difference between AC and DC servo motor repair?
AC (brushless) servo motors need bearing, winding, encoder and brake work with encoder alignment. Brushed DC servo motors also need brush and commutator work. We repair both types.
02Our equipment
The Universal Servo Motor Repair Equipment
What is the Universal Servo Motor Repair Equipment?
It is a test and alignment system (Mitchell TI-5000JX and TI-3000JX) that reads and aligns the encoder or resolver and runs a servo motor without its original drive, for 180+ brands. Star Automations uses it as India's first universal servo motor test system. More about it.
What can the Universal Servo Motor Repair Equipment do?
It checks and aligns the encoder or resolver to the rotor, programs encoders where the model needs it, runs the motor on no load and under load and records speed, current and vibration for the test report.
Do you need my drive to test the motor?
No. The system drives the motor itself, so it works with any brand and also when the original drive is faulty or unavailable.
03Difference
Star Automations compared with a normal repair centre
What is the difference between a normal motor repair centre and Star Automations?
A normal motor repair centre is set up for ordinary motors. Star Automations is set up for servo motors, with a universal test and alignment system, encoder programming, a run test without the original drive and a printed test report. The table below shows the difference in plain terms.
| A normal motor repair centre (typical) | Star Automations | |
|---|---|---|
| Set up for | Ordinary induction and DC motors | Servo motors of 180+ brands |
| Encoder or resolver alignment | Usually not done, or done by eye | Aligned to the rotor on the Universal Servo Motor Repair Equipment |
| Encoder programming | Usually not available | Done where the model needs it, with Mitchell equipment |
| Run test | Often a no-load run on a supply | Run without the original drive, no-load and load, speed and current checked |
| Original drive needed | Yes, or the motor is not proved | No |
| Paper with the motor | Often none | Printed test report |
| Warranty | Varies | 3 months to 1 year, stated on each quotation |
This describes typical set-ups in general terms. Every shop is different, and a good motor shop is still the right place for ordinary motors.
04Troubleshooting
Finding the fault
How do I know if a servo motor is working?
With power off, the shaft should turn smoothly by hand. Check the cables and connectors, the brake and the alarm on the drive. A full check needs the motor to be run with a drive or a test system while speed, current and feedback are watched. That is what our bench test does.
Why is my servo not moving?
Common reasons are a drive alarm, a brake that is not releasing, a damaged cable or connector, an encoder or resolver fault, or a motor that is mechanically jammed. After the motor was opened, wrong encoder alignment is another very common reason.
What are the symptoms of a bad servo motor?
Noise or vibration, heat, jerky or uneven motion, loss of torque, positioning errors, brake problems, and alarms for overload, overcurrent or feedback. See our alarm guides for specific codes.
What are the symptoms of a bad encoder?
Encoder or feedback alarms, loss of position, a motor that runs rough or runs away, an alarm only when the motor is hot or moving, and a drive that does not recognise the motor. Servo encoder alarms explains the common ones.
What are common problems with servo motor encoders?
Dirt, oil or moisture inside, damaged cable or connector, worn or damaged disc or sensor, a failed backup battery on absolute types, and shifted alignment after the motor is opened. See encoder repair.
How do I troubleshoot a servo motor?
Note the alarm code, power off and discharge the drive, turn the shaft by hand, check cables, connectors and brake, and look at what changed recently. If the mechanism is free and the alarm stays, bench testing separates a motor fault from a drive fault.
What are the common causes of servo motor failure?
Bearing wear, encoder or resolver faults, overheating from overload or poor cooling, winding or insulation damage, brake faults, contamination by oil, coolant or dust, and cable or connector damage.
Why is my servo motor making a buzzing sound?
Buzzing often points to unstable gains, a loose or misaligned encoder, a worn bearing, or a mechanical resonance. If it began after the motor was opened, check the encoder or resolver alignment first.
05Practical
Turnaround, warranty and what to send
How long does repair take?
Emergency repair is done the same day where the fault and parts allow, urgent in 3 working days and standard in 7 working days, counted from when the motor reaches our bench and the quote is approved.
What warranty do you give?
3 months to 1 year, stated on each quotation.
What should I send?
A clear photo of the nameplate, the alarm code and a short note on the machine and what was done. We confirm repairability before you courier the motor.
How much does servo motor repair cost?
It depends on the fault, the motor size and the parts needed. See what affects the cost, or send the nameplate for a quote.
Can I get an exchange motor while mine is repaired?
If we hold a matching motor, Servo Swap ships a tested exchange unit. Mark "line down" on the request form.
Send the nameplate. We confirm repairability before you courier.
WhatsApp a nameplate photo and the alarm code to +91 97866 22233, or email info@starautomations.com.
Brand names identify the units we repair. Star Automations is an independent multi-brand repair company and is not an OEM service centre.
→How it works
From nameplate photo to a tested motor in 7 steps
One route for servo motors, encoders and drives. You see the price before any work starts, and the report before the unit leaves our bench.
- 1 · Nameplate photoSend it on WhatsApp or the form
- 2 · Repairable? QuoteUsually the same working day
- 3 · Courier or pickupThe unit reaches our bench
- 4 · Bench diagnosisInsulation, windings, brake, encoder
- 5 · RepairFailed parts, bearings, seals, brake
- 6 · Align and run-testEncoder aligned; no-load and load run
- 7 · Report and dispatchPrinted test report with the unit
- Line down?Servo Swap ships a tested unit first. How Servo Swap works
EmergencySame day*
Urgent3 working days
Standard7 working days
*Where the fault and parts allow. Turnaround counts from when the unit reaches our bench and the quote is approved.