Good and bad detection and judgment method of motor
First, if the detection of AC three-phase motor is good or bad
1. Shake the table and shake the table with 500V. Shake the insulation resistance of the wire on the three terminals to the motor casing. It should be above 0.5M, indicating that there is no short circuit to the ground (Yantai motor maintenance).
2, multimeter test: measure the resistance of A / B / C three-phase, whether it is equal, it should be similar, too much difference can also turn, but not long, remember that the larger the motor, the smaller the resistance! But Can not be three-phase are 0 ohms, unless you are particularly large, such as motors above 50KW! Remember that if the resistance of the 6 terminals of the speed control motor can be different!
3, check the bearings, fans, the general wrapped around the motor will be replaced! Because sometimes the bearing lock will burn the motor!
4. The no-load current of the motor is generally 10% to 50% of the rated current. Sometimes the motor idle current is still zero!
5. When the rated current of the motor is running, it is running at full load, and the output power is basically 100%. The running current is small, indicating that the motor output power is small and it is light load operation.
Second, how to detect the quality of AC single-phase motors
Use 500V megohmmeter to measure the insulation resistance of the motor winding and the outer casing, which should not be less than 0.5 megohm; use a multimeter to measure the winding leads, no broken wire; the above all meet the requirements, the motor is good.
It is convenient to use the pointer multimeter to detect the quality of the capacitor (there is also a digital meter with a capacitor file, which can be directly measured).
Turn the multimeter to 1K or 10K resistor, measure the 2 leads of the capacitor, and the pointer will quickly deflect to the right and slowly return to the left capacitor. The capacitor is always deflected to the right; the capacitor is not moved. Internal disconnection or no capacity. In this way, only the quality of the capacitor can be judged.
3. The quality of DC motor
First look at the presence or absence of a broken wire and measure whether the resistance is normal.
If it is a brushed DC motor, you can rotate the rotor and use a multimeter to measure whether the output DC power is normal.
If it is a brushless DC motor and the three-phase is taken out, the rotor can be rotated, and the alternating voltage of the output is measured by a multimeter.
The output voltage is proportional to the speed.
