Aug 21, 2017
The brush current motor is a dc motor with fixed main magnetic pole and brush on the stator of the brush motor. The rotor is fitted with armature winding and commutator.
Dc power supply of electricity through the brush and commutator into the armature winding, produce the armature current, the magnetic fields produced by the armature current with the main magnetic field interact to produce electromagnetic torque, the motor spins load.Due to the existence of brush and commutator, the brush motor has a complex structure, poor reliability, more failure, large maintenance work, short life, and easy to generate electromagnetic interference.
The working principle of brushless current machine:
The working principle diagram of brush dc motor is shown in figure 2-1.There is a magnet in the fixed part of the brush dc motor, which is called the main magnetic pole.The fixed part also has the brush.The rotating part has a ring core and winding winding around a ring core.
There is a gap between the stator and the rotor.The armature coil, which is connected by A and X conductors, is placed on the armature core and the ends and ends of the coil are connected to two circular pieces of copper, which is called A commutator.The commutator segment is insulated from each other, and the integral part of the commutator is called the commutator.The commutator is fixed on the shaft, and the commutator is also insulated from the shaft.A pair of fixed immovable brush B1 and B2 are placed on the commutator. When the armature is rotated, the armature coil is connected to the external circuit through the commutator and the brush
Brush current motor type:
There is a brush disk winding motor.There is a brush coil winding motor bonded to a cylinder of rare earth materials. The coil winding of enameled copper wire is placed in the cylinder body, which makes up the rotor.The phase of the motor depends on the mechanical phase switch.The mechanical phase switch is used to adjust the voltage phase by using fixed carbon brush and rotating copper for friction.This kind of motor has been worn in the use of the brush, and the life of the motor is hard to exceed 2000h.At the same time, due to the speed of the motor is higher, must adopt two stage gear reduction, this has brought two problems, one is the noise is bigger, the second is the efficiency loss is big, after reduction motor rated efficiency, often can only reach 68% ~ 68%.The capacity of the battery used in the electric bicycle is limited, which is generally 36V / 12Ah, such as the low efficiency of the motor, which will increase the power consumption and affect the renewal mileage
A brush printed winding motor.There are brush printed winding motor to print copper foil as winding, motor weight loss.Because this motor is all produced on automatic production line, the process has reliable guarantee, which can improve the life of the motor to 3000h, the noise is reduced greatly, and the efficiency is increased to 72% ~ 76%.However, this motor has a "humming" high frequency noise, and it is still not ideal after the gear deceleration, and the use of the brush commutator can't improve the motor life
A brush pressed winding motor.The motor can be improved to 74% ~ 78% by pressing the copper wire around a new windings.This kind of motor is still used by many electric bicycle manufacturers, but its efficiency, noise and life defects are still problems that must be improved