Motor Selection Key Indicators: Performance, Cost and Service Life

Motors are widely used, but if you want them to be fully functional, you need to select the type of motor. However, just determining the type of motor is not enough, but also according to the individual performance of the motor to select the appropriate parameters. Generally need to refer to the following performance indicators.

1. The number of output revolutions

The number of revolutions per minute that the motor can output, generally expressed in units “min-1” or “rpm”, also known as the speed, is the most basic performance of the motor. A motor that rotates 5000 revolutions per minute is called “5000 min-1 (5000 rpm)”. Together with torque, it determines the output power of the motor.

2. Torque

The force produced by the motor. The higher the torque, the higher the load capacity in “Nm”. For a motor with a torque expressed as “20 Nm”, this means that if a 1-meter-long rod is attached to the rotating shaft, it can exert a force of 20 N at the tip.

3. Positioning accuracy

This is the performance required of motors (such as stepper motors) that perform precise operations. The term “repeat positioning accuracy” refers to the error in repeat positioning. The stepping motors (stepping servo motors) equipped with encoders introduced by Minebea Sanmei can realize higher positioning accuracy.

4. Noise performance

Depending on the product application, the noise performance of the motor may be required. Reducing noise in the drive process can make the motor quieter. There are three types of noise generated by motors: electromagnetic noise, ventilation noise and mechanical noise.

5. Cost

Cost is also an important factor in choosing a motor. The price depends on the type, size and output power of the motor. The quality of the permanent magnets, electromagnetic steel plates and bearings used also has a great impact on the price. The higher the performance, the higher the cost, so care must be taken not to overspecify when selecting a motor. Repair and replacement costs and maintainability should also be considered when selecting motors for long-term use in equipment and other facilities.

6. Service life

The service life of the motor is basically related to the service life of the bearings. The main reason for short bearing life is grease degradation and rolling fatigue. For motors with electronic circuits, the service life of the capacitor may be the service life of the motor; for motors with gearboxes, the service life of the gear may be the service life of the motor.