The principle of three phase asynchronous motor

When to three in the stator mini electric motor winding through a symmetric three alternating current (ac),creates a to synchronous speed n1 along the circle space inside the stator and rotor rotate clockwise rotating magnetic field.Due to a rotating magnetic field in the n1 speed rotation,the rotor conductor is still at the beginning,so the rotor conductor will cut the stator rotating magnetic field and induced electromotive force (judge the direction of the induced
electromotive force with the right-hand rule).Because the guide was short circuit ring short meet on both ends of the conductor,in under the action of induction electromotive force,the rotor conductors will be wholesalemotor.blogspot.com consistent with the direction of induction electromotive force induced current.Rotor current carrying conductor in the role of the stator magnetic field by electromagnetic force (judge force direction with the left www.dongfeng-motor.com hand rule).

Electromagnetic force to the rotor shaft of the electromagnetic torque,driving rotor spinning in the direction of the rotating magnetic field.By analyzing the working principle of the motor can be summarized as follows: when the three motor stator winding Angle of 120 degrees (the difference between electric),bubbled into three alternating current (ac),will produce a rotating magnetic field,the rotating magnetic field cutting rotor winding,thus produce induced current in the rotor winding is closed (rotor winding path),the rotor of current-carrying conductor under the effect of the stator rotating magnetic field will produce electromagnetic force,as to form the electromagnetic torque on the motor shaft,motor rotation,and the motor rotation direction gasoline generator is the same as the rotating magnetic field direction.

The difference between motor and brushless motors

From now in general use in the industry,there are two main types of motor:efficient rare earth permanent magnet has a motor and the efficient rare earth permanent magnet brushless motor on the market at present most Electric bicycle is still stay in brush motor stage.A brush motor using mechanical commutation,the technical requirements of the control system is low,relative cost is lower than the brushless motor,A brush motor starting torque slightly larger than the brushless motor. But the fatal weakness is:life is short,large noise and low efficiency.Long-term use of carbon brush wear serious,it is easy to damage.At the same time wear produced huge amounts of carbon dust,These dust fall in gear oil,gear oil accelerate dries up,the motor noise further increased.A brush motor use to within a year or so will need to replace carbon brush,You will find a charge mileage bought less than two-thirds,and climbing when power is insufficient,will burn out the controller.This is because the motor After the replacement of carbon brush and commutator also be ground out a groove,reduce carbon brush contact area,poor contact of carbon brush after electrify which sparks and accelerate oxidation in electricalmotor1.blogspot.com To implement and copper,acmotortrading.blogspot.com lead to the undesirable phenomenon. Brushless motor electronic commutation replace the mechanical commutation,technically superior to brush motor.

Because of brushless motor without gear or gear,the motor,reduce wear and tear The unreliability.Its efficiency within a certain range of current ratio has a brush motor with high efficiency.Brushless motor driving up almost no motor lamination noise,and for up to 10 years to life On.According to the comparison,both brushless motor is better than have a brush.At present,there have been some electric bicycle factory with motor is to switch to the original brushless electric Machine.Brushless motor must be the development direction of electric bicycle. Consumers can come up from appearance to identify motor belongs to "brush" or "no brush" :first,"brushless electric wire" eight root,and the "brush" electric wire to the positive and negative There are two root;Secondly,with the induction motor hand when the drive motor,before and after the brushless motor rotation is easy,and before the "brush" motors turn easily,after when transfer is quite tight.

Brushless dc motor

Brushless dc motor is a kind of self-control type permanent magnet synchronous motor,but is a square

wave power supply,and usually say acmotortrading.blogspot.com of the permanent magnet synchronous motor is a sine wave power supply.Is said to be "dc motor",mainly considering the brushless motor controller is equivalent to a dc motor brush and commutator,to achieve "electronic commutation," Look from the dc side is equal to the dc motor.Dc servo used in dc motor,brushless dc motor is not; Brushless dc motor and ac servo motor In fact is one thing,be ac synchronous motor (ac 6.5hp gasoline generator set permanent magnet synchronous servo motor).Q (C):motor of log? A: n1 = 60 * f / 2 p p said general motors to count,the number of 2 p is.1 to include N gasoline generator spare parts pole and S pole,pole,of course,is a logarithmic twice.Synchronous motor mechanical speed = 60 * running frequency/log; Asynchronous electrical machinery speed = 60 * running frequency * (1 - slip rate)/log