An electric motor is a device that converts electrical energy into mechanical energy. It uses the energized coil to generate a rotating magnetic field and acts on the rotor to form a magneto-electric power rotating torque. Motors are divided into DC motors and AC motors according to different power sources. Most of the motors in the power system are AC motors, which can be synchronous motors or asynchronous motors. The motor is mainly composed of a stator and a rotor, and the direction of the energized wire in the magnetic field is related to the direction of the current and the direction of the magnetic field line (magnetic field direction). The working principle of the motor is that the force of the magnetic field on the current causes the motor to rotate.
Purpose and Application
Among the various motors, the most widely used is the AC asynchronous motor (also known as the induction motor). It is easy to use, reliable in operation, low in price and firm in structure, but has a low power factor and is difficult to regulate. Synchronous motors are commonly used in power machines with large capacity and low speed. The synchronous motor not only has a high power factor, but also its speed has nothing to do with the size of the load, but only depends on the frequency of the grid. Work is more stable. DC motors are often used where wide-range speed regulation is required. But it has a commutator, complex structure, high price, difficult maintenance, and is not suitable for harsh environments. After the 1970s, with the development of power electronics technology, the speed regulation technology of AC motors has become more and more mature, and the price of equipment has been reduced, which has begun to be applied. The maximum output mechanical power that the motor can bear under the specified working mode without causing the motor to overheat is called its rated power. When using it, pay attention to the regulations on the nameplate. When the motor is running, pay attention to matching the characteristics of its load with the characteristics of the motor to avoid flying or stalling. Electric motors can provide a wide range of power, from milliwatts to tens of thousands of kilowatts. The use and control of the motor are very convenient, and it has the capabilities of self-starting, accelerating, braking, reversing, and stopping. Generally, when the motor speed is adjusted, its output power will change with the speed.