How does ac motor speed control
The rated speed n = 60f/p (1-s) = synchronous speed of N1 (1-s) f power frequency The speed adjustment of the power frequency is changed by using the frequency converter, the speed adjustment range is large, the stability is smooth and the mechanical properties are hard. This is the reduction in the nominal load speed. It belongs to stepless speed adjustment. Suitable for most three-phase squirrel cage asynchronous motor. The speed adjustment of the magnetic pole is changed, it is the speed adjustment, the speed adjustment is poor, and it is commonly used for metal cutting machine tool. Change the speed adjustment. (1) rotor circuit resistance: used for ac winding asynchronous motor. The speed of adjustment is small, the resistance has to consume power, the motor is inefficient. It is used for cranes. (2) it changes the voltage regulation of the power supply, the speed adjustment is small, the torque decreases greatly with the voltage drop, and the three-phase machine is not used. For single-phase motor speed adjustment, such as fan searching. (3) a series of speed adjustment, the essence is that the rotor introduces additional electromotive force, and changes its size to speed adjustment. It is also used only for winding motor, but efficiency is improved.
There are three kinds of speed regulating methods One is to use a transducer to change the frequency of the power supply. The second is to change the extreme number of the motor (the requirement for the motor). Three is the slide differential governor. This doesn't actually change the motor speed. It is the variation of the differential clutch that is connected to the motor shaft, changing the speed of the clutch output shaft.
Buy the speed adjustment machine ~ 4 files ~ the external one governor ~ can be adjusted More expensive,
Ac motor is not adjustable and should be added converter.Electromagnetic coupling. It is used only for slip motors. By changing the current of excitation coil, the mechanism is simple, but the control power is small. Do not operate at a low speed.
