The classification of the cooling fan
1. A cooling fan is the use of electricity to provide power supply, motor stator and rotor of two most,
on the stator poles ( Winding type or permanent magnet) , the rotor winding, after electrify, also formed on the rotor magnetic field ( The magnetic poles) And an Angle between stator and rotor poles have, in the stator magnetic field ( N pole and S pole) Attract each other, is the motor rotation. Change the brush seat, can change the Angle of the rotor poles ( Assumptions in the stator pole to start edge Angle, the pole to the other side of the rotor, the rotor pole is pointing in the direction of the stator pole motor direction of rotation) Direction, so as to change the direction of rotation of the machine.
2. Ac cooling fan is used in substation with power supply: only one winding single-phase ac motor, the rotor cage type.
when single-phase sinusoidal current through the stator winding, the motor can produce an alternating magnetic field, the magnetic field strength and direction of interplanting sine law of change at any time, but on the spatial orientation is fixed, so the magnetic field is also called alternation pulse magnetic field. This alternation pulse magnetic field can be decomposed into two at the same speed and direction of rotation are instead of a rotating magnetic field, when the rotor static, the two rotating magnetic field generated in the rotor torque of two equal and opposite, making synthetic torque is zero, so the motor can't turn. When we use the motor rotates in the direction of a force, If clockwise) When the rotation of the rotor and clockwise direction magnetic field cutting lines of magnetic force between the smaller; The rotation of the rotor and counterclockwise direction magnetic field cutting lines of magnetic force between the movement. This balance is broken, the total electromagnetic torque generated by the rotor will no longer be zero, rotor spun along the driving direction.
3. From an electrical switching magnet games way can be divided into two kinds of, with brush and heat dissipation, have motor life is short, the spark is produced. Cooling motor without carbon brush wear long life, easy to high speed running no spark, has gradually replaced the brush.