An overview of AC motor
AC motor has become the most commonly used motor because of the great development of AC power system. Compared with DC motor, AC motor has no commutator (see commutation of DC motor), so it is simple in structure, easy to manufacture and firm, and easy to make motor with high speed, high voltage, large current and large capacity. The coverage of AC motor power greatly, from a few watts to several 101000 watts, even millions of kilowatts. At the beginning of 1980s, the largest turbogenerator had reached 1 million 500 thousand KW.
Power supply for AC motor
AC motor generally adopts three-phase system, because three-phase AC motor has obvious advantage in terms of performance index, raw material utilization and price compared with single-phase motor. The three phase motor of the same power is smaller than the single phase motor, light weight and low price. The three phase motor has the ability of self starting. The single phase motor has no starting torque. In order to solve the starting problem, some special measures should be taken. The torque of a single phase motor is pulsating, and the noise is relatively large, but the required power is relatively simple, especially in the family. Therefore, the small household motor and the machine used for the instrument use the single phase motor.