What is the difference between generator with brush and brushless?

1. Principle difference: brush motor adopts mechanical commutation, magnetic pole does not move, cfuel rotates. When the motor works, the cfuel and commutator rotate, the magnet and carbon brush do not rotate, and the alternating change of cfuel current direction is accomplished by the commutator and brush that rotates with the motor. Brushless motor adopts electronic commutation, cfuel does not move and magnetic pole rotates.

2. Difference of speed regulation mode: In fact, both motors are controlled by voltage regulation, only because brushless DC uses electronic commutation, digital control is required. Brushless DC is commutated by carbon brush, and can be controlled by traditional analog circuits such as silicon controlled, which is relatively simple.

Differences in performance:

▶ 1. The brush motor has simple structure, long development time and mature technology.
As early as the birth of motor in the nineteenth century, the practical motor generated was brushless form, i.e. AC squirrel-cage asynchronous motor, which has been widely used since the generation of AC. However, there are many insurmountable defects in asynchronous motor, so that the development of motor technology is slow.
▶ 2. DC brush motor has fast response speed and large starting torque:
DC brush motor has fast starting response, large starting torque, smooth speed change, and can hardly feel vibration from zero to maximum speed. It can drive larger load when starting. Brushless motor has large starting resistance (inductance), so it has small power factor, relatively small starting torque, humming when starting, accompanied by strong vibration, small driving load when starting.
▶ 3. DC brush motor runs smoothly with good starting and braking effect:
Brush motors are regulated by voltage, so start and brake smoothly and run smoothly at constant speed. Brushless motors are usually controlled by digital frequency conversion. First AC is changed into DC, then DC into AC. The speed is controlled by frequency change. Therefore, brushless motors run unevenly when starting and braking, with large vibration, and only when the speed is constant will they run smoothly.
▶ 4. High control accuracy of DC brush motor:
DC brush motor is usually used together with gearbox and decoder, which makes the motor output power larger and control accuracy higher. The control accuracy can reach 0.01 mm, and can stop moving parts almost anywhere you want. All precision machine tools use DC motor to control accuracy.
▶ 5. DC brush motor has low cost and easy maintenance.
Due to its simple structure, low production cost, many manufacturers and mature technology, DC brush motor is widely used and very inexpensive. Brushless motor technology is immature, the price is high and the application range is limited. It should be mainly used in constant speed equipment, such as variable frequency air conditioning, refrigeratory, etc. Brushless motor damage can only be replaced.
▶ 6. Brushless, low interference:
The brushless motor removes the brushes and the most direct change is the absence of the electric sparks generated when the brushless motor is running, which greatly reduces the interference of the electric sparks on the remote control radio equipment.

Post time: Apr-20-2021