Gear reduction motor is a fixed speed reduction motor. Once the speed ratio is selected, the motor is selected, and the final output speed is fixed. However, in practical use, there are still many situations that require changes in speed, such as the spindle speed of lathes, the mixing shaft speed of various mixers, and the conveyor speed when conveying different items. How to adjust the speed is a topic of great concern to engineering and technical personnel. Below is a brief description of various speed control methods applied in engineering.

1. Gradual speed regulation and pole changing speed regulation are the simplest and most economical methods of speed regulation. But only limited to small and medium-sized capacity (below 2kw) and situations with few starting times. Usually, there can only be two speeds, and the achievable speed ratio is relatively small (1:2-6), with a maximum of three speeds; In certain industries, such as lathes, gearboxes with gears are often used for stepped speed regulation. Although there is a child speed, the speed range is not large.  

2. Stepless speed regulation can be divided into mechanical and electrical types. The common method for the former is to insert a mechanical continuously variable speed device (mainly belt disc and friction disc) at the connection between the motor and the gearbox. Its advantages are smooth speed regulation, simple structure, and suitability for harsh environments; The disadvantage is that the speed range is small (generally within 1: 10), and the belt and friction disc are consumable parts that require regular maintenance and replacement. The latter involves cascade speed regulation of asynchronous motors, rotor resistance speed regulation, or voltage regulation speed regulation of DC motors.