This article mainly introduces the brushed motor. First of all, it introduces the principle of the brushed motor. Secondly, it introduces the structure diagram of the brushed motor. Finally, the advantages and disadvantages of the brushed motor are explained. Follow the small series together to find out.
Brush motor introductionA brush motor is a rotary motor incorporating a brush device that converts electrical energy into mechanical energy (motor) or mechanical energy into electrical energy (generator). Unlike brushless motors, brush devices are used to introduce or extract voltage and current. The brush motor is the basis of all motors. It has the characteristics of quick starting, fast braking, smooth speed regulation over a wide range, and relatively simple control circuit.
Brush motor principle
The brush motor adopts mechanical commutation, the magnetic pole does not move, and the coil rotates. When the motor is working, the coil and the commutator rotate, the magnet and the carbon brush do not rotate, and the alternation of the direction of the coil current is accomplished by the commutator and the brush that the motor rotates.
In brushed motors, this process consists of arranging the two power input terminals of each group of coils into a ring, which are separated from each other by insulating materials to form a cylinder-like thing that is integrated with the motor shaft. A small column (carbon brush) made of two carbon elements presses two points on the ring cylinder's power input ring at two specific fixed positions under spring pressure to energize one set of coils.
As the motor rotates, different coils or different two poles of the same coil are energized at different times so that the NS pole of the coil generating a magnetic field and the NS pole of the nearest permanent magnet stator have a suitable angle difference, magnetic field anisotropic attraction, and the same sex Repulse, generate power, push the motor to rotate. The carbon electrode slides on the coil terminal, like a brush on the surface of the object, so it is called a carbon “brushâ€.
Sliding each other will rub the carbon brush and cause loss. The carbon brush needs to be replaced on a regular basis. The carbon brush and the coil connection will alternately open and close, sparks will occur, electromagnetic breakdown will occur, and electronic equipment will be disturbed.
Brush motor structure
This figure explains the Stator, Rotor, Brushes, Commutator, Magnet, and Windings of brush motors very well.
The advantages and disadvantages of brushed motorsadvantage
1, simple structure
The brush motor mechanism is simple, easy to manufacture and process, easy to maintain, and easy to control; DC motor also has the characteristics of fast response, large starting torque, ability to provide rated torque from zero speed to rated speed.
2. Smooth operation, good starting and braking effect
The brush motor regulates pressure and speed, so the starting and braking are stable, and the constant speed operation is also stable. The brushless motor is usually a digital frequency conversion control. It first turns the AC into DC, and then DC and then into AC. The speed is controlled by the frequency change. Therefore, the brushless motor does not run stably when starting and braking, and the vibration is large. Only when the speed is constant Will be stable.
3, high control accuracy
A brush motor is usually used together with a reduction gearbox and a decoder to make the output power of the motor larger and the control precision higher. The control accuracy can reach 0.01 millimeters, and almost all the moving parts can be stopped at any desired place. All precision machine tools use DC motor control accuracy.
Shortcomings
a. There is friction between the brush and the commutator, resulting in reduced efficiency, increased noise, and easy heating. The life of a brushed motor is several times shorter than without a brush.
b, maintenance trouble, need to constantly change the brush.
c. Because of the large resistance, low efficiency and low output power.
d. Brush and commutator friction can cause sparks, and interference is large.
Shenzhen Yidashun Technology Co., Ltd. , https://www.ydsadapter.com