1. Adjust the armature power supply voltage U
Changing the armature voltage mainly involves reducing the armature voltage from the rated voltage downwards and changing the speed downwards from the rated speed of the motor, which belongs to the constant torque speed regulation method. For systems that require stepless smooth speed regulation within a certain range, this method is the best. The time constant encountered by changes in armature current is small and can respond quickly, but requires a large capacity adjustable DC power supply.
2. Change the main magnetic flux of the motor φ
Changing the magnetic flux can achieve stepless smooth speed regulation, but it can only weaken the magnetic flux and adjust the speed upwards from the rated speed of the motor, which is a constant power speed regulation method. When the armature current changes, the time constant encountered is much larger and the response speed is slower. However, the required power capacity is small.
3. Change the resistance R of the armature circuit
The method of adjusting speed by connecting resistors outside the armature circuit of an electric motor is simple in equipment and easy to operate. But it can only have stepwise speed regulation, with poor smoothness of speed regulation and relatively soft mechanical characteristics; Consuming a large amount of electrical energy on the speed control resistor. There are many drawbacks to changing resistance speed regulation, and it is currently rarely adopted.