Why Do Motors Fail?
Electric motors are complex machines with multiple moving parts. They are vulnerable to common performance issues that reduce their life span. Everyone wants their motors to last a long time and knowing the problems that can affect their dependability and operation is important. There are six main issues that can result in premature motor failure.
1. Electrical overload. Excessive voltage supply or overwork by drawing more current will lead to overheating issues. As the motor works harder or under an unusual load, heat can lead to motor failure.
More than 55% of insulating failures in motors occur due to overheating. Several factors that contribute to overheating are poor power quality and/or a high-temperature operating environment. For every 10oc that the temperature of a motor rises, the insulation life is reduced by half.
2. Low resistance. This is the most common reason for motor failure is usually an electrical issue. Degradation of motor windings by heat will pave the way for short-circuits and leakages, which then result in motor failure.
3. Contamination. Dust and debris will raise the internal temperature of a motor and keep it from cooling, which leads to excessive heat over a longer period of time. This generally occurs without proper maintenance or venting for particles. Care needs to be practiced in loading grease into guns and the injector tip needs to be protected from dirt as grease can introduce contaminates into bearings.
4. Start-stop frequency. This plays a big role in heat damage. Excessively starting, stopping, and starting won’t allow the motor to cool properly. Components can be compromised in a high-heat environment.
5. Vibration. Severe vibrations can raise the temperature to levels that are not safe and can result in components that are stressed beyond their heat capacity. Vibrating motorscan create noise, cause safety problems, lead to degradation in plant working conditions and cause machinery to consume excessive power.
6. Moisture. Moisture and humidity are problems if a motor is de-energized long enough to drop near the dew point temperature. Moisture weakens the dielectric strength of the electrical varnish and other insulating materials. It also contributes to bearing erosion and other electrical components.
Moisture can be reduced if the motor is kept warm. Motors stored inside should be pre-warmed for several hours before starting. This dries the moisture accumulated in the motor winding. (Space heaters can also be used to keep the motor warm
Motor failures continue to happen until maintenance solves the core issue. a maintenance plan: Thorough, routine maintenance ensures individual components within the electrical system get the attention they need to minimize overwork and overheating.
IER can help you with your commercial motors, pumps and drives. We sell, repair and maintain commercial motors. Call 614-298-1600 to learn more.