What factors determine the lifespan of an electric motor

The lifespan of an electric motor is not determined by a single factor but is the result of the combined effects of design quality, operating conditions, environmental conditions, and maintenance standards, constituting a systematic engineering process

Core determinants

 

Design and manufacturing quality: This is the cornerstone of motor lifespan.

Insulation material: The insulation level of the motor winding (such as F level, H level) determines its high temperature resistance. Insulation materials are the key to aging failure, and their lifespan is extremely sensitive to temperature. For every 10 ℃ increase in temperature, the lifespan may be reduced by half. ‌

Bearing quality: Bearings are the most vulnerable components in mechanical parts, and their lifespan directly determines the mechanical lifespan of the motor. High quality bearings can significantly extend the overall lifespan of the motor. ‌

Heat dissipation design: Good heat dissipation can effectively control the temperature rise of the motor and avoid accelerated insulation aging caused by overheating

 

Operating conditions and loads: The usage mode has a direct impact on the lifespan

Load characteristics: Long term overload operation (such as exceeding 20% of rated power) will significantly increase winding current and accelerate insulation aging. ‌

Frequent starting and stopping can generate instantaneous voltage surges and shorten the lifespan of the motor. ‌

Operating habits: Extreme operations such as sudden acceleration and braking can increase the motor load. Incorrect operation (such as stalling) may burn out the motor in a short period of time

 

Environmental conditions: The external environment is an important external variable

Temperature and humidity: High temperature and humidity environments can reduce insulation resistance and accelerate material aging. For every 10 ℃ increase in ambient temperature, the lifespan of some motors may be halved. ‌

Moisture can also cause the winding to become damp and leak electricity. ‌

Corrosiveness and dust: In environments such as sandstorms, coastal salt spray, chemical corrosive media, or explosive dust, the motor casing, seals, and internal components can accelerate corrosion, wear, or block heat dissipation channels, resulting in a much shorter lifespan than design expectations. ‌

Voltage stability: Unstable grid voltage or overvoltage/undervoltage operation can affect the electrical performance of motors and accelerate insulation aging. ‌

 

Maintenance level: This is the key to extending the actual service life of the motor.

Regular lubrication: Bearing lubrication failure is the root cause of over 60% of bearing failures. Regularly replacing lubricating grease can extend the lifespan of bearings by several times. ‌

Cleaning and Inspection: Regularly cleaning the motor casing and cooling channels, checking the wear of brushes, dust rings, and bearings, and replacing them in a timely manner can effectively prevent malfunctions. ‌

System maintenance: For applications such as electric vehicles, regular replacement of coolant and inspection of seals are also necessaryIn summary, although the design lifespan of motors is usually between 10 and 20 years, their actual service life largely depends on proper use and timely maintenance. ‌

Good maintenance can make the actual service life of some motors exceed 200% of the design life.

 

 

From the analysis of the operating characteristics of the motor, the two major factors that affect the service life of the motor are electrical performance and mechanical properties. As long as there are no problems with the components related to the motor, the motor can operate and be used normally. Using this perspective to evaluate, the length of motor lifespan seems like a false proposition; But from the perspective of motor users, they are particularly concerned about this issue, so we will conduct a basic analysis of the factors that affect the performance level of the motor from another angle.

 

In the maintenance and use instructions of most motor products, there is a quality assurance cycle based on correct use and maintenance. That is, once a quality problem occurs during normal maintenance and use according to the rated parameters of the motor, the manufacturer will repair or replace it free of charge according to the actual situation. In fact, this is a quality assurance commitment for early quality failures of the motor, not the concept of the end of the motor's life.

 

The electrical performance level of a motor mainly depends on the balance between the heat generated by the current during operation and the ventilation and heat dissipation. As long as the insulation material of the motor winding does not age and there are no obvious quality defects, the electrical performance of the motor is generally safe. However, in actual operation, overcurrent caused by unstable voltage, overload and other factors can accelerate the aging of motor winding insulation, seriously affecting the service life of the motor. The vibration problem during the operation of the same motor may cause unexpected instability in the connection parts of the motor winding, leading to open circuit faults in the motor winding. If similar issues can be ruled out, the normal use time of the motor will be longer.

 

 

The main factors affecting the mechanical performance level of the motor are the operating quality of the motor's bearing system and the strength of the shaft. As long as necessary inspections and maintenance are carried out according to the maintenance requirements of the motor bearings, such as lubrication and regular replacement of bearings, if there are no obvious manufacturing or design defects in the motor shaft, the motor is safe for rated operation. However, in the actual operation of the motor, unreasonable design of the bearing system and untimely operation and maintenance of the motor may lead to premature mechanical performance problems, which can seriously affect the quality of the motor winding.

In summary, the service life of a motor depends not only on the manufacturing quality level of the motor body, but also on its maintenance in the later stage.