How to judge the quality of DC motor？

If you want to quickly judge the quality of the DC motor, you should first check whether the motor is disconnected, and measure whether the resistance is normal. If it is a brushed DC motor, you can turn the rotor and use a multimeter to measure whether the output DC is normal. If it is a brushless DC motor, three phases can be drawn out, the rotor can be rotated, and a multimeter can be used to measure whether the output voltage is normal, and whether the output voltage is proportional to the speed. Here are a few ways to quickly judge the quality of a DC motor.

1. When connecting the positive and negative poles, there will be a lot of resistance, indicating that the line is normal. Instead, it means that there is a breakpoint inside the motor.

2. Under rated voltage, the error between the measured speed and the nominal speed should not exceed 10%.

3. Add 1.2 times the rated voltage, run for 2 minutes, and observe whether there is any abnormality.

4. After the DC motor runs to a stable temperature, the surface temperature of the motor should not exceed 80 degrees Celsius. If it exceeds this value, it means that the temperature of the motor rises quickly and cannot pass.

5. Rotate the DC motor by hand. If you feel a noticeable resistance, it means there is a short circuit inside the motor, and smooth rotation is normal.

6. Observe the reverse spark when the power is turned on. If there is no spark or few sparks, it means that it is normal, and it is not good for the sparks to form a line. Do not use if ring fire occurs.

7. When the temperature rises steadily, stop the machine and measure the winding resistance with a multimeter. A few tenths to a few ohms belong to the normal range.

After the above series of inspections, it was observed that the DC motor was fine. Use a multimeter to measure the voltage between the commutator segments. If there is the same regular voltage between the two segments, the winding is normal and can be used with confidence.