Principle of brushless DC motor

1. The stator of a brushless DC motor is composed of a coil winding armature, while the rotor uses a permanent magnet.

 

2. If only a fixed DC current is applied to the motor, the magnetic field generated by the motor will remain unchanged, and it will not be able to start rotating.

 

3. In order to make the motor run, the rotor position must be monitored in real time, and the corresponding current must be provided to different phases of the motor according to the position to generate a rotating magnetic field with uniformly changing direction.

 

4. The center tap of the coil of the motor stator is connected to the power supply POWER, and the end points of each phase are connected to the power tube. When the position sensor is turned on, the G pole of the power tube will contact 12V, causing the power tube to turn on and energize the corresponding coil.

 

5. As the rotor rotates, the three position sensors will turn on in sequence, so that the corresponding phase coils are energized in sequence, and the direction of the magnetic field generated by the stator continues to change, thereby driving the rotor to start rotating.

 

6. The advantages of brushless DC motors include:
It can replace traditional DC motor speed regulation, inverter plus variable frequency motor speed regulation, and asynchronous motor speed regulation schemes.

 

7. This motor not only inherits the advantages of traditional DC motors, but also eliminates the carbon brush and slip ring structure.

 

8. It can provide high power output at low speed and directly drive heavy loads without a reducer.

 

9. The motor is small in size, light in weight and has high output force.

 

10. It has good torque characteristics, especially excellent performance at medium and low speeds, with large starting torque and small starting current.

 

11. The motor supports stepless speed regulation, a wide speed regulation range, and strong overload capacity.

 

12. The soft start and soft stop characteristics are good, and the braking performance is excellent, so the mechanical brake or electromagnetic brake device can be omitted.

 

13. The motor is highly efficient. Since there is no excitation loss and carbon brush loss, and the multi-stage deceleration loss is eliminated, the comprehensive power saving rate can reach 20% to 60%.