Motor is a kind of rotary electric machine, it is a device converts electrical energy into mechanical energy. It is using electric coil creates a rotating magnetic field and is used to turn the mouse cage closure of aluminum frame to form dynamic rotating magnetic torque. Its working principle is magnetic field in the current stress, make motor rotate.
Motor is mainly composed of stator and rotor, the motion direction of electrify wire in the magnetic field relate to the current direction and magnetic induction line direction. According to different use of power, motor can be divided into dc motor and ac motor, motor in the electric power system is mostly ac motor, synchronous motor or induction motor.
When motor running need to pay attention to make it load characteristic and motor characteristic phase match, avoid aerodyne or shut down. Motor can provide rate of work range is big, from milliwatt magnitude to million kilowatt. It is very convenient to use and control, has self starting, accelerating, braking, reverse, stopper live etc. ability, and can satisfy the various operation requirements; the work efficiency of the motor is higher, and no smoke, odor, polluting the environment, noise is small. Because of its series of advantages, it so widely used in all walks of life.
Machine tool, drilling machine, water pump, belt conveyor fan etc. need motor drive; Electric locomotive, elevator, need motor traction. Family life of the electric fan, refrigerator, washing machine, and even all kinds of motor toys is inseparable from the motor. Motor has been used in all aspects of life in modern society.
Moreover all kinds of motors are used in ac asynchronous motor (also known as induction motor). It is convenient to use, reliable operation, low cost, firm structure, but power factor is low, speed regulation is also more difficult. Large capacity low speed power machine is commonly used motor. Not only synchronous motor power factor is high, but its speed has nothing to do with the load size, only depends on the line frequency. Work is more stable. In require wide scope speed regulation occasion more use dc motor. But it has a commutator, the structure is complex, the price is expensive, maintenance is difficult, not suitable for bad environment.