When designing a compact DC motor drive solution, the user must first make a choice: should he choose a brushed (DC) motor or a brushless (BLDC) motor?
Undoubtedly, both types of motors have their own advantages and disadvantages, but which type is more suitable for a specific application? This requires analysis from the characteristics of the two:
1. Service life
The commutation system of the brushed motor directly affects its service life, and the commutation system is directly affected by the load conditions. The large current, high speed, reverse motion and high-intensity vibration generated during operation will reduce its service life;
The brushless motor cancels the mechanical commutation design and uses electronic commutation, which greatly prolongs the life and reduces maintenance, and can estimate the motor life relatively accurately. For example, the ball bearing will limit the service life of the motor, which can be quite The service life of the motor can be inferred accurately by the design life of the bearing.
2.Motor speed and torque
The brushed motor is affected by the commutation system, and the running speed is generally lower than 10,000 rpm. When running at overspeed, the service life of the motor will be greatly shortened due to increased electrical and mechanical wear;
Brushless motors of the same size and magnetic structure can run at higher speeds, even over 100,000 rpm;
In terms of torque, the starting torque of the brushed motor is better than that of the brushless motor. Compared with the brushless motor, the starting resistance of the brushed motor is small (inductive reactance), and the speed change is stable.
4. Environmental conditions for motor use
Brushed commutation systems can generate sparks that can cause electromagnetic interference, and graphite dust from graphite brushes can contaminate cleanroom, vacuum, or optical applications.
5. Motor control and operation
The brushed motor is easy to operate, as long as the two connection terminals have sufficient voltage, the motor can start to work;
Brushless motors require additional electronic commutation control equipment, and wiring is more complex;
But when precise control is required, the cost of control equipment, sensors, and wiring costs are the same for both types of motors.
Summarize:
Brushless motors for high-speed applications have advantages;
Long life brushless motor has advantages;
The adaptability of brushless motor is stronger;
In applications that require fast acceleration and high starting torque, brushed motors are more suitable;
Simple drive applications have the advantage of brushed motor wiring and control costs, and precise control is similar.
