What is the principle of the motor?
Release time：
2024-06-18
source：
A machine that converts electrical energy into mechanical energy.
DC motor - A motor that rotates with direct current is called a DC motor. Due to the different ways of connecting the magnetic field circuit and the armature circuit, it can be divided into series-excited motors, split-excited motors, and compound-excited motors;
AC motor - A motor that rotates with alternating current is called an AC motor. There are many types, mainly:
① Rectifier motor - This type of motor is made by using a series-excited DC generator as an AC motor. Because the alternating current rotates in both the magnetic field and the armature circuit at the same time, the direction of the torque remains unchanged, and the machine rotates continuously. This type of motor is also called a "universal motor" because it can use both AC and DC. Vacuum cleaners, sewing machines and other household appliances often use this type of motor.
② Synchronous motor - A motor whose armature rotates from one to the next, exactly in the same cycle as the direction of the current. This type of motor cannot start by itself, and must be connected to the AC power after reaching the appropriate frequency with another motor or special auxiliary winding. If the load changes and the speed changes, the speed will not match the frequency of the AC power, which is enough to cause the motor to lose its pace, stop or cause damage. Due to many restrictions, it is not widely used.
③ Induction motor - a device that places the rotor in a rotating magnetic field and rotates the rotor due to the action of eddy current. The rotating magnetic field is not created by mechanical methods, but by passing AC current through several pairs of electromagnets, causing their magnetic properties to change cyclically, which can be regarded as a rotating magnetic field. Usually, three-phase induction motors (with three pairs of magnets) are used. The movement of a DC motor is just opposite to that of a DC generator. In a generator, the induced current is formed by the induced electromotive force, so they are in the same direction. In the motor, the direction of the induced electromotive force supplied by the external power source is opposite to the direction of the armature current I. The induction motor in the AC motor has a strong induced current (eddy current) generated in the rotating magnetic field. The copper rod on the rotor continuously cuts the magnetic lines of force. According to Lenz's law, this induced current has the effect of resisting the magnetic field and the relative motion of the rotor, so the rotor rotates with the magnetic field. However, the rotor rotation speed is not as high as the speed of magnetic field transformation, otherwise the magnetic lines of force cannot be cut by the copper rod.
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What are the common materials for motors?
The stator magnetic field (main magnetic field) of the electromagnetic DC motor is composed of an iron core and an excitation winding. According to the different excitation methods (called excitation in the old standard), it can be divided into series-excited DC motors, shunt-excited DC motors, separately-excited DC motors, and compound-excited DC motors.
What are the common powers of motors?
Common motor powers include: three-phase 220 motors, 3.5 amperes per kilowatt. Commonly used 380 motors, 2 amperes per kilowatt. Low-voltage 660 motors, 1.2 amperes per kilowatt. High-voltage 3,000-volt motors, 1 ampere per kilowatt. High-voltage 6,000-volt motors, 8 kilowatts per ampere.
What is the principle of the motor?
DC motor - A motor that rotates with direct current is called a DC motor. Due to the different ways of connecting the magnetic field circuit and the armature circuit, it can be divided into series-excited motors, split-excited motors, and compound-excited motors.
