Common causes of motor failure

Wednesday - 26/04/2017 09:21

Common causes of motor failure

Modern motors may be more efficient and reliable than their ancestors, but sometimes error may occur.
How long does the motor actually last before the failure? The answer is often controversial, some manufacturers say 30,000 hours, the others suggested that they can power up to 40,000 hours.

However, most manufacturers are agree that motors last much longer when maintained properly.

Understanding the health status of the motor requires a range of tools and techniques, as well as complete record keeping and periodic maintenance. This allows the engineers to easily identify trends or weakness.

Weakened insulation

Almost half of the electrical faults in the motor begin to weaken the insulation of individual wires in the surrounding motor coils. This is usually caused by thermal stress, contamination and movement of the winding due to the magnetic forces during start and stop of the motor.

Overheating can also lead to rapid deterioration of the insulation of the winding —the insulation life is halved for every 10 ° C increase in temperature.
DC motor

When the power quality is poor or when the motor is forced to operate in a high-temperature environment, Overheating may occur.


Contamination is another major cause of motor failure. Contaminants include air dust, dirt or any abrasive substance entering the motor. When they come into contact with the motor, the foreign matter can cause concave the bearing raceways and balls to produce high vibration and wear.

Fortunately, it is quite easy to prevent contamination. The main sources of contamination include dirty tools, working areas and hands. The motors can also be contaminated by foreign matter in the lubricant and cleaning solutions
motor dc

Engineers shall keep the work area, tools and equipment clean to help reduce contamination failures. In addition, in the laying of space, the company should try to keep the motor components and operating areas away from the grinder, in order to reduce the amount of foreign matter may be contaminated motor.

Lack of maintenance

Careful preventative maintenance is the key to reliable, long-life operation of motors and generators. It also helps reduce unplanned production downtime or repair for a long time to shut down.

The first step in preventative maintenance is to understand how often necessary to test the motor. It depends on age, condition and quality of the machine and their operating environment.

Static tests are a simple way to identify weaknesses in the motor windings. Test the concentrated windings and insulation resistance and inter-turn and phase insulation conditions.
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These tests can be performed using the appropriate equipment, without the motor off site, thereby reducing downtime.

Motor failure can lead to downtime, meaning that the company can lose thousands of pounds when stopping every minute of action.

Rather than expose themselves to downtime, clients should require periodic motor tests and analysis, preferably every six months to ensure that motors are healthy, efficient and reliable.

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