In modern industrial and technological fields, brushless motors have been widely used due to their many advantages such as high efficiency, low noise, and long lifespan. However, like any mechanical device, brushless motors may also experience some malfunctions during operation. Understanding these common faults and their repair methods is crucial for ensuring the normal operation of brushless motors.

1、 Brushless motor cannot start

1. Power supply issue
The starting of a brushless motor first requires a stable power supply. If the power cord is damaged, the plug is loose, or the power switch is damaged, it may cause the motor to be unable to obtain normal operating voltage. At this point, the power line should be carefully inspected to see if there is any damage or breakage. If necessary, a new power line should be replaced in a timely manner. At the same time, ensure a tight connection between the plug and the socket, and fully insert the plug into the socket. For power switches, a multimeter can be used to check if they are conducting properly. If the switch is damaged, it should be replaced promptly.

2. Motor winding fault
Short circuit or open circuit of motor winding is one of the common reasons for failure to start. Winding short circuit may be caused by insulation damage, overload operation, and other reasons. And a circuit break may be due to poor welding of the winding wire or wire breakage during long-term vibration. Using an insulation resistance meter (megohmmeter) can check the insulation resistance of the winding. If the insulation resistance is found to be too low, it indicates a short circuit fault. For the short-circuit section, it is necessary to locate the short-circuit point and repair the insulation layer. If the winding is broken, the resistance of the winding can be detected through the resistance range of the multimeter. After determining the position of the broken circuit, the damaged winding part can be re welded or replaced.

3. Controller malfunction
The controller of a brushless motor is responsible for controlling the start, stop, and speed of the motor. If the controller malfunctions, such as a damaged control chip or a faulty drive circuit, the motor cannot start normally. Check if the input and output signals of the controller are normal. An oscilloscope can be used to observe the waveform of the control signal. If the waveform is abnormal, it may be necessary to replace the control chip of the controller or the entire controller. At the same time, it is necessary to check the power circuit of the controller to ensure that it can provide stable operating voltage for the controller.

2、 Abnormal noise during motor operation

1. Bearing issues
Bearing wear or poor lubrication are common causes of abnormal noise. As the motor runs, the bearings continue to rotate, and long-term use may cause wear and tear, resulting in friction or vibration sounds during motor operation. Check the wear of the bearings. If the bearing wear is light, friction can be reduced by adding an appropriate amount of lubricating grease. If the wear is severe, new bearings need to be replaced. When replacing bearings, it is important to choose the appropriate type of bearing and ensure proper installation. After installation, appropriate adjustments should be made to ensure smooth motor operation.

2. Unbalanced rotor
The rotor may experience uneven quality distribution during the manufacturing process, or may become unbalanced due to collisions, loose parts, and other reasons during use. This imbalance will cause the motor to produce vibration and noise during operation. Perform dynamic balance testing on the rotor to determine the position and degree of imbalance. The balance of the rotor can be adjusted by adding counterweights at appropriate positions on the rotor. If the rotor is severely damaged, a new rotor may need to be replaced.

3. There are foreign objects inside the motor
During the production process of the motor or in poor operating conditions, foreign objects may enter the interior of the motor. These foreign objects will collide with the components of the motor during operation, producing abnormal noise. Remove the motor casing and carefully inspect for any foreign objects inside the motor. If foreign objects are found, clean them up and check whether the motor components are damaged. After cleaning the foreign objects, reassemble the motor to ensure that the interior of the motor is clean and tidy.

3、 Abnormal motor speed

1. Speed sensor malfunction
Brushless motors are usually equipped with speed sensors to provide feedback on the motor's speed information. If the speed sensor malfunctions, such as sensor damage, open or short circuits in the connecting wires between the sensor and the controller, it will cause the controller to be unable to accurately obtain the motor speed, resulting in abnormal speed. Firstly, check if the connection wire between the speed sensor and the controller is normal, and check if the circuit is damaged, open or short circuited. If the circuit is normal, use a multimeter to check whether the output signal of the speed sensor is within the normal working range. If the sensor is damaged, it needs to be replaced with a speed sensor of the same model.

2. Controller parameter setting error
The parameter settings of the controller will directly affect the speed of the motor. If the parameter settings are incorrect, such as incorrect speed settings or improper control mode selection, the motor speed will not meet expectations. Check the parameter settings of the controller, determine the correct parameter settings by reviewing the controller manual or contacting the manufacturer's technical support. According to actual needs, readjust the speed setting value, control mode and other parameters to restore the motor speed to normal.

3. Abnormal load changes
Sudden increase or decrease in the load carried by the motor, exceeding the rated load range of the motor, can also cause changes in the motor speed. For example, in the transmission system, situations such as belt breakage or jamming, loose couplings, etc. can cause sudden changes in load. Check the load condition of the motor and check if the load connection part is normal, such as whether the belt is loose, whether the coupling is tightly connected, etc. For situations where the load suddenly increases, it is necessary to check for any faults in the load, such as mechanical components getting stuck. If the load suddenly decreases, it may be necessary to adjust the parameters of the controller to adapt to the new load situation.

In short, understanding the common faults and maintenance methods of brushless motors can help us promptly and effectively deal with problems, ensure the normal operation of brushless motors, extend their service life, and provide strong guarantees for the stable operation of various equipment.