Simple method for motor fault detection
Date：2023-10-14 Author：XINDA MOTOR
1 Visual
inspection Visually check whether the motor terminals are intact, whether the brush box is broken, and whether the motor is damaged.
2. Measuring resistance
1.1 Measure the resistance of the subor and the rotor respectively. That is, measure the resistance between D1 and D2 and between A1 and A2. If the resistance value is less than 1A or smaller, it means it is normal; if the resistance value is large, it means there is a coil fault or brush fault.
2.2 Measure the insulation resistance: Measure the resistance between each terminal and the machine base respectively. If the resistance value is larger, it means it is normal; if the resistance value is less than 1A or less, it is an insulation fault.
3. Idling test
According to relevant regulations, DC series motors are not allowed to operate with no load or light load (the motor is prone to overrun). Therefore, the idling test should be conducted at low voltage (less than 30% of the rated voltage as much as possible).
3.1 If the motor has not been removed from the car, the car should be erected so that the driving wheels are suspended in the air.
3.2 If the motor has been removed from the vehicle, first check whether there is a bearing on the motor shaft extension. If there is no bearing, special tooling is required. It is recommended to return it to the factory for inspection. If there is a bearing, an idling test can be performed.
3.3 Motor terminals A1 and D1 are connected to an external 12V power supply (switch control should be added), and A2 and D2 are connected with copper wires for short circuit. If the motor works, it is normal; if the motor does not work, switch to a 24 V power supply (switch control should be added), and if it still does not work, the motor is faulty. If there is an adjustable power supply, the power supply should be gradually and slowly increased from low to high.
3.4 The idling time should not be too long. If the motor moves, it means the motor is normal and should be stopped.
4 Note
4.1 If possible, you should first check whether the power supply is supplying power to the motor in the car. That is, when the power is on, press the accelerator pedal to the bottom and measure the motor input voltage. You can measure between A1 and D1 or between A2 and D2.
4.2 After testing items 1 and 2, it should be possible to basically determine whether the motor is faulty. The idling test should be conducted in a professional institution as much as possible.
4.3 Measuring the motor should be carried out under safe conditions.
4.3.1 Ensure the safety of electricity use.
4.3.2 During the idling experiment, the motor speed may be very high, which may cause danger. If you feel that the motor has abnormal sound or the speed is too high, you should cut off the power immediately.
XINDA