Complete Guide to know Servo Motor Failure and its Causes


This specific class of motors is far more precise than your regular motors. That is why servo motors have a number of applications in robotics, automated manufacturing, and computer numerical control (CNC) machinery. So it would be a bummer if you land yourself with a failed servo motor. Not only because of the halt in production lines but also because of the bills you’ll have to cash out in finding the solution.

Repair a Failed Servo Motor or Buy a New One?

But one of the most important questions to ask is: Should I repair the failed servo motor or buy a new one? The repair process could be time-consuming and buying a new one could be expensive. When deciding on whether or not you replace or repair your servo motor, there are a number of factors you should consider i.e.

  • What was the cause of motor failure?
  • Do you have a spare unit available?
  • Determine the cost of downtime if the machine is down.
  • How much would a new motor cost? Will it be available immediately or consume time in delivery and being put into service?
  • What is the warranty for repair?
  • Do you have a repair vendor willing to provide a free quote in time?
  • If the repair work costs more than 50% of the cost of buying a new motor, which would be done more quickly?

Take all these factors into consideration and choose the paths that will minimize your costs and the time consumed.  

Causes of Servo Motor Failure:

There are many causes of motor failure. This is not surprising as the environment in which the motor is placed can be quite hazardous. The most common causes of motor failure are listed below along with some tips to help avoid these situations

Contamination: The motor can easily be contaminated by errant oil, coolant, cutting fluid and can cause the failure of the components of your servo motor including winding failure, bearing failure, failure of the encoder, etc. You can protect your motor from contamination by ensuring the attached gearboxes are not over-filled. Also, consider ultra-sealing your motor windings to protect them from contamination.

Bad Bearings: This is also a very common cause of motor failure. Bearings tend to wear out over time and a lack of preventive maintenance can also increase the likelihood of failure. A bearing failure undetected can also cause other components surrounding it to breakdown. This can be prevented by ensuring regular maintenance checks and removal of any contaminants which may have seeped through. 


Degradation of Electrical Components: Electrical components i.e. capacitors, diodes, resistors, etc. in your servo motor will age over time and breakdown. This is why it is necessary to keep track of how long your motor has been running and when to have the components replaced in case they have started to wear out.


Winding and Cable Failure: Bad cables and windings are common causes of servo motor failure. Shortage in cables, power faults, poor insulation, poor quality of cables/windings used, degradation over time, there are numerous reasons why this could happen. In order to make sure that your motor is free from these conditions, use good quality cables and windings and ensure testing before use. In case your motor needs new windings, make sure your motor is precision wound per factory specifications. Brake Failure: The brake pads in your servo motor are also prone to wear and tear over time.  Environmental conditions can also cause wearing out of brake pads. The solution is to keep track of how long your brake pad has been in service and immediate replacement if you notice signs of degradation.



Demagnetization of Permanent Magnets: If the servo motor is overloaded the permanent magnets may be demagnetized. If the magnets demagnetize, the servo motor will not be able to handle the loads it is designed for. For this, you need to make sure that you’re not overloading your servo motor.

Failure Due to Electrostatic Discharge: Electrostatic discharge is the sudden flow of electricity between two charged objects. This can shock electronic components in the motor leading to memory loss in the system.  In order to prevent ESD ensure that all your electronic components are handled while grounded.


Failure Due to Improper Installation: This is also one of the leading causes of motor failure. If the servo motor is installed in a hurry there is a chance of positioning being off, improper techniques can also be the issue at hand. For this make sure your servo motor is installed by an experienced dealer.




In short, if proper maintenance is performed along with correct usage, your servo motor will last longer.  If you suspect a bearing going bad due to loud noise, it is best to send into a professional Servo Motor Repairs facility for service and bearing change.  If you wait too long, a more catastrophic repair will surely result, causing longer machine downtime and higher costs.

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Rashid Asmani dolwa April 7, 2021 - 2:04 pm

Thanks for your guide . Kindly what might be the cause of aservo drive motor to ran awrong direction.

Samuel Ladipo October 9, 2021 - 3:46 pm

Thanks for this education,

My servo motor on my A3 UV printer intermittently stops going right until I allow to rest for a while.

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