With a multimeter to determine whether the single-phase or Three Phase Electric Motor is burned only the winding winding DC resistance of only 1 ohm above the small motor. Three Phase Electric Motor is not burned the method of discrimination is relatively simple, with a multimeter to test the three-phase winding DC resistance and resistance is balanced, if the imbalance can determine the Three Phase Electric Motor is burned. Single-phase motor general start winding DC resistance is greater than the operating winding, the most simple method of discrimination is;
1. First with a multimeter to detect the common end to run the winding side and start the winding side of the DC resistance
2. Then use the multimeter to measure the DC resistance at the winding end to the start winding end.
3. If the arithmetic of the two measurements in "1" is not equal to the measured value in "2", the motor must have been burned! If equal, it is best to compare with the same type of motor, or find the motor factory parameters to compare. To determine the quality of the motor to add a little, the amount of single-phase motor should be disconnected capacitor. Single-phase motor short circuit is that you have to have a normal resistance as a reference. Simple point with the smell and see two law like.
Normal Three Phase Electric Motor, the phase resistance value should be almost or equal, but the specific value and the specific motor has a relationship, there should be no value.
According to personal experience, the motor burn is generally insulated layer burned, phase short circuit or short circuit to the shell. The phase resistance should be almost the same. The motor burned the general short-circuit on the shell of the majority, shake the table with the shake to know, 500V shake table, do not use 1000V shake table, so more dangerous, easy to burn the motor.
First, if the detection of motor is good or bad?
1, shake table shake, 500V shake the table can be, shake the three terminals on the line of the motor housing insulation resistance, should be more than 0.5M Europe on the description of no short circuit.
2, multimeter test: test A / B / C three-phase resistance, whether it is equal, it should be almost bad too much can turn, but not long, remember the greater the motor, the smaller the resistance! But can not be three-phase are 0 Europe, unless you are particularly large, such as more than 50KW motor! Remember that if the speed of the motor 6-terminal resistance is not the same yo!
3, check the bearings, fans, the general winding motor let the whole change! Because sometimes the bearing lock will burn the motor yo!
4, the motor no-load current is generally rated current of 10% to 50%, and sometimes the motor idle current is also zero yo!
5, the motor rated current running, is full load operation, the output power is basically 100%. Running current is small, indicating that the motor output power becomes smaller, is light load operation.
6, no three-phase electricity, find a washing machine start capacitor, then 220V can also turn yo!
Second, how to detect single-phase motor is good or bad?
Measure the insulation resistance of the motor windings and housings with a 500V megger, and should not be less than 0.5 megohms. Measure the windings with a multimeter and do not break the wires. The above are in line with the requirements and the motor is good.
Detection of the capacitor with a good or bad standard pointer (also with a digital table with a capacitive scale, can be measured directly).