Can the multimeter also measure the quality of the motor?
Many electricians are accustomed to using a shaking meter to measure the quality of the motor in their daily work. This is undoubtedly a common and relatively safe test method. Today I will share with you how to use a multimeter to measure the quality of the motor. The table can also measure the relevant situation, so as not to delay the work process!
Measurement method of three-phase motor:
Put the gear of the digital multimeter on the 200Ω range, and measure the three-phase power lines on the motor two by two. If the resistance values of the three measurements are equal or very close, it means that the three-phase windings are in good conduction.
Then open the junction box of the motor, remove the connecting copper sheet on the terminal, that is, disconnect the connection of the U, V, and W windings, put the multimeter at the maximum position of the resistance gear, or use a multimeter pen Measure any end of the three windings U, V, and W in pairs. If the resistance values show infinity, it means that the insulation between phases of the motor is normal.
Finally, use the maximum resistance range of the multimeter to measure the resistance value of any end of U, V, W and the casing. If the resistance value is infinite, it means that the motor insulation is no problem, and it can be started by power-on test.
Measurement methods for single-phase motors:
When measuring a single-phase motor, you can put the gear of the digital multimeter in the 2K gear, and first measure the resistance of the main winding, which is generally tens to hundreds of Ω, which varies according to the power of the motor.
The resistance of the secondary winding is slightly larger or the same as that of the main winding. If the resistance of the main and auxiliary windings is normal, then measure the insulation between the main and auxiliary windings. On any terminal of the winding, the other test lead is grounded on any end of the auxiliary winding. If the insulation resistance is infinite, it is normal. Finally, measure the insulation resistance of the two windings and the casing. One test lead is connected to the winding, and one test lead is connected to the motor casing. It is normal to display infinity where the upper part can be turned on.
