1. Different motor structure
1) There is a coil in the AC motor. The general resistance of this coil is not very large, that is, about 100 ohms. Taking the phase shift as an example, it has a starting winding and a running winding.
2) The internal structure of the DC motor is mainly composed of the stator and the rotor. In the past, many were brushed motors. The rotor has a brush, and there is a Hall sensor on the motor to detect the position. Alternating contact, which forms an alternating magnetic field and continuously rotates. The size of DC motors is generally smaller than that of AC. Many companies now use DC brushless motors.
2. The working principle is different
1) The power supply voltage of the AC motor is AC, and the motor can be controlled by AC switching components, such as thyristors. The voltage resistance must be sufficient when using thyristors. For example, for 220AV AC motors, you can use 400VAC, even 600VAC.
2) For DC motor, its power supply voltage is DC input, which can be controlled by PWM technology. PWM is a signal with adjustable duty cycle, which can be input with different. The following figure is the output diagram of the brushless DC motor. The upper and lower arms are respectively turned on, and the motor output is 310V. DC can be stepless speed regulation, the speed series can be adjusted to very high, and can increase the feedback signal, closed-loop speed regulation, and brake function, that is to say, it can be quickly stopped within a certain period of time, output The stability is better.
3. Different output power
Generally, DC motors have less power than AC motors, especially brushless motors, which overcome many of the shortcomings of brushed motors, but also have their own disadvantages, such as resonance
