AC motors can be roughly divided into commutator-type motors, synchronous motors and induction motors. Both synchronous motors and induction motors are AC motors whose rotational speed is determined by the rotating magnetic field.
The so-called rotating magnetic field here refers to the phenomenon that when multi-phase alternating currents such as three-phase alternating current and two-phase alternating current are connected to the stator coils, the generated magnetic field rotates at the speed ( = synchronous speed) determined by the frequency of the multi-phase alternating current.
The rotor rotates by being attracted by the rotating magnetic field, and AC motors are classified according to the difference in their rotation methods. Rotating magnetic field type AC motors (collective term for synchronous motors and induction motors) are roughly divided into motors that use 2-wire household AC 100V as the power supply and 3-wire industrial AC 200V as the power supply.
The previous called single-phase motor, the latter called three-phase motor.Recently, semiconductor element inverters have been adopted in the utilized power conversion circuits to drive three-phase AC motors. This is to control the voltage and frequency through the inverter and operate at the desired rotational speed and torque.
(1)Commutator type motor
The main uses are for electric vacuum cleaners, power tools and juicers. That is, in the fields that require high-speed operation with single-phase AC as the power supply. The general statement contains the meaning that it can operate with AC or DC (that is, AC/DC dual-use). The structure is the same in principle as a DC series-excited motor, but in the case of AC, the following situations must be considered.
(2)Synchronous motor
A synchronous motor is a motor whose rotational speed is the same as the synchronous speed.
