How to evaluate a single-phase motor's quality with a digital multimeter
1. Turn the multimeter to the electric barrier 200 ohm block, and measure the resistance of the three phases respectively. If the resistance of the three phases is the same and the difference is not large, it can be preliminarily judged that the three-phase windings are basically normal and there is no inter-turn short circuit.
2. Measure whether it is grounded, because the motor burns out, and sometimes it is accompanied by grounding. If one end of the two test leads of ×1K or ×10k touches the wire head and the other end touches the case, it is good. If it moves and the amplitude is large, it is not good.
3. If the motor is a single-phase motor, you can measure the resistance of the main winding U1 and U2 and the auxiliary winding Z1 and Z2. Generally, the resistance of the auxiliary winding is greater than the resistance of the main winding. If the resistance of the auxiliary winding is smaller than that of the main winding If the resistance value is higher, it means that the motor is burnt out.
Extended information
Precautions for using a digital multimeter:
1. Use a meter that meets the requirements of the field application
2. Use a meter with a current input fuse, and check the fuse before measuring the current
3. Check the test leads for physical damage before measurement
4. Check the continuity of the test lead with a meter
5. Only use safety handles and insulated test leads
6. Use a watch with a concave socket
7. Select the appropriate function and range when measuring
8. Confirm that the table is in good condition
9. Follow the product safety manual
10. First disconnect the red test line
11. Don’t work alone
12. Use a meter with overload protection in the electric barrier
13. When measuring current without a current clamp, cut off the power supply of the circuit before connecting it to the circuit
14. In the case of high voltage and high current, pay attention to use appropriate equipment, such as high voltage probe, current clamp
