Understand the difference between DC motor / AC motor / electronic rectifier motor
Principles of DC and AC motors
The DC motor uses a carbon brush and a rectifying ring to change the direction of the current and magnetic field electrodes in the rotating armature. The interaction between the inner rotor and the stationary permanent magnet will cause the motor to rotate.
The DC motor is limited to the brush system and has a service life of 1000-1500 hours. If it is under extreme load, it will be less than 100 hours. Under the condition of good working conditions, the operating life of some motors may reach 15,000 hours. In addition, high-speed rotation is limited by rectification, typically up to 10,000 times per minute (RPM).
DC motors are more efficient, but there are certain specific losses, and the factors that cause failure include: initial resistance of the winding, brush friction and eddy current loss.
AC induction motors use a series of windings that are controlled by the AC input voltage and generate the stator magnetic field, which in turn produces the rotor magnetic field. The synchronous motor is another AC motor, and its power frequency accuracy during operation is high. When a current passes through a slip ring or permanent magnet, a magnetic field is generated. Synchronous motors run faster than induction motors, which are limited by the slip ring of the asynchronous motor.
An AC motor means that the operating value of the device will correspond to a specific point on the performance curve, which will be consistent with the peak efficiency of the motor. If it is not operated according to the value corresponding to this point, the efficiency of the motor will drop sharply. The AC motor generates an induced current on the rotor, which in turn generates a magnetic field, which leads to additional energy consumption. Therefore, AC motors are not as efficient as DC motors. In fact, the efficiency of a DC motor is more than 30% higher than that of an AC motor because the permanent magnet will generate a secondary magnetic field.
