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Advantages&Disadvantages of BLDC Motor

Update:22-04-2020
Summary:

The BLDC motor, a typical mechatronics product, include […]

The BLDC motor, a typical mechatronics product, includes the motor body and drive.

Advantages of BLDC motor:

1. With excellent linear mechanical characteristics of DC motor, wide speed range, stepless speed regulation, wide speed range;

2. Excellent torque characteristics, good medium and low speed torque, large starting torque, small starting current, strong overload capacity;

3. Soft start, soft stop and good braking characteristics, can save the original mechanical brake or electromagnetic brake device;

4. High efficiency. The BLDC motor has no excitation loss compared with the AC NanYang Motor , and no brush friction loss and no spark compared to the brushed DC motor;

5. High reliability, good stability, strong adaptability and simple maintenance;

6. Small size, light weight and large output;

7. Resistant to bumpy vibration, low noise, small vibration, smooth operation and long service life.

Disadvantages of BLDC motors:

1. Cost: Rare earth permanent magnets are much more expensive than other permanent magnets, so the cost of the motor increases.

2. Limited constant power range: A large constant power range is critical to achieving high vehicle efficiency. It is impossible for a permanent magnet BLDC motor to obtain a maximum speed greater than twice the base speed.

3. Safety: In the manufacturing process of motors, large-scale rare earth permanent magnets can attract scattered metal objects, so they may be dangerous. In the event of a vehicle crash, if the wheels spin freely and the motor is still excited by permanent magnets, a high voltage will appear at the terminals of the motor, which may endanger passengers or rescuers.

4. Magnet demagnetization: The permanent magnet can be demagnetized by large reverse magnetomotive force and high temperature. For each permanent magnetic material, the critical demagnetization force is different. When cooling the motor, especially if the motor is compact, care must be taken.

5. High-speed performance: It is impossible for permanent magnets to use a surface-mounted motor to achieve high speeds, because it is limited by the mechanical strength of the assembly between the rotor yoke and the permanent magnets.