A brushless motor refers to a brushless DC motor, which is composed of a motor, its main body and a driver. It is a typical electromechanical integration product. Since the brushless DC motor operates in a self-controlled manner, it does not have an additional starting winding on the rotor like a synchronous motor that starts under heavy load under variable frequency speed regulation, and it will not produce oscillation and loss of synchronization when the load changes suddenly.
The permanent magnets of small and medium-capacity brushless DC motors now mostly use rare earth neodymium iron boron materials with high magnetic energy product. Therefore, the volume of the rare earth permanent magnet brushless motor is smaller than that of the three-phase asynchronous motor of the same capacity by one frame size.
Difference:
1. Scope of application:
Brushless motor: usually used on equipment with relatively high control requirements and high speed, such as model aircraft , precision instruments and meters and other equipment that strictly control the motor speed and reach a very high speed.
Carbon brush motors: Usually power equipment uses brush motors, such as hair dryers, factory motors, household range hoods, etc. In addition, the speed of series motors can also reach very high speeds, but Due to the wear of carbon brushes, the service life is not as good as that of brushless motors.
2. Service life:
Brushless motor: Usually the service life is on the order of tens of thousands of hours, but the service life of brushless motors also varies greatly due to different bearings.
Carbon brush motor: Usually the continuous working life of a brushed motor ranges from a few hundred to more than 1,000 hours. When the use limit is reached, the carbon brush needs to be replaced, otherwise it will easily cause bearing wear.
3. Effect of use:
Brushless motor: usually digital frequency control, with strong controllability, it can easily go from a few revolutions per minute to tens of thousands of revolutions per minute. accomplish.
Carbon brush motor: The old carbon brush motor generally has a constant working speed after starting, and it is not easy to adjust the speed. The series motor can also reach 20,000 rpm, but its service life will be relatively short.
4. Energy saving:
Relatively speaking, brushless motors controlled by variable frequency technology will save much more energy than series motors. The most typical ones are variable frequency air conditioners and refrigerators.
5. In terms of future maintenance, carbon brush motors need to replace carbon brushes. If not replaced in time, the motor will be damaged. Brushless motors have a long service life, usually more than 10 times that of brushed motors. , but if it breaks down, the motor needs to be replaced, but daily maintenance is basically unnecessary.
6. The noise aspect has nothing to do with whether it is a brushed motor or not. It mainly depends on the coordination between the bearings and the internal components of the motor.
7. In addition to the overall dimensions (outer diameter, length, shaft diameter, etc.), weight, voltage range, no-load current, maximum current and other parameters, the parameter indicators of the model brushless motor are indispensable. Indicator - KV value, this value is a unique performance parameter of the brushless motor and an important data for judging the performance characteristics of the brushless motor.
Extended information
Advantages and disadvantages of brushed motors
Advantages: cheap price and simple technology.
Disadvantages: low conversion efficiency; relatively loud noise; low speed; short life.
Advantages and disadvantages of brushless motors
Advantages: high speed; large output torque; long life.
Disadvantages: high technical requirements and high cost.
Brush motors use mechanical commutation, the magnetic poles do not move and the coil rotates. When the motor is working, the coil and commutator rotate, but the magnets and carbon brushes do not rotate. The alternating changes in the direction of the coil current are completed by the phase commutator and brushes that rotate with the motor.
In brushed motors, this process is to arrange the two power input terminals of each group of coils into a ring in sequence, separated from each other by insulating materials, to form a cylinder-like thing, and The motor shaft is integrated into one, and the power supply passes through two small pillars (carbon brushes) made of carbon elements. Under the action of spring pressure, the coil power input is pressed from two specific fixed positions to two points on the annular cylinder. , energize a set of coils.
Reference materials: Baidu Encyclopedia - Brushless Motor Baidu Encyclopedia - Brush Motor