Methods and steps for measuring three-phase power with a multimeter
1. We know that household 220V AC power is very dangerous, as long as it does not directly contact the wire ends, there is no danger. Direct contact with 380V industrial electricity is also very dangerous. Its 50HZ frequency and 380V high voltage pose greater harm to the human body. So it is necessary to know its characteristics and usage points. The important point is to never touch any wire ends or metal parts with bare hands at any time. Because the three wires of the 380V power supply are all live wires, any contact with them can create a dangerous electric shock voltage of 220V with the ground. So pay special attention to safe use of electricity. Firstly, confirm that the multimeter probes are in good contact and turn the multimeter range switch to the AC position.
2. Firstly, confirm that the multimeter probes are in good contact and turn the multimeter range switch to the AC position. According to the principle of using a multimeter from high to low, it is estimated that there is no 1KV power supply to be tested, so choose the 500V range.
3. For the safety of operation, people can stand on dry wooden boards or stools. In this way, the human body and the earth are insulated. If you come into contact with a live wire on a wooden building, there is no danger. However, at this time, you are an extension of this wire and cannot come into contact with anything else, including the earth. If contact forms a circuit, it is dangerous. Now bring the multimeter closer to the power supply, that is, the contactor. The two probes of the multimeter are in contact with the two metal parts of the contactor, without distinguishing between black probes or U, V,W. Two lines are enough.
4. At this point, you can see from the panel of the multimeter that the pointer is deflected to the right and stops moving when it reaches a certain position. This value is the voltage between these two lines. The reading looks like this: on the panel of the multimeter, there is a V symbol on the left end of the second arc, indicating voltage. Voltage can be divided into AC and DC, that is, waveform and straight line. We are measuring alternating current. The value is on this arc. Since we are using 500 gears and the scale is 10, 50, and 250, we calculate each gear by 5 times. Our 500 is 10 times more than 50, and you can see the scale line of 50, which is exactly at the value of 38. Therefore, adding another 10 times is 380V. The same goes for other gears, so you can understand and read the values.
5. Then keep one pen in the same position and connect the other pen to the third wire. It can also be UV, UW,VW.
6. The measured results are all 380V. The characteristic of this three-phase electricity is that there is a phase voltage of 380 between every two lines, which is also a line voltage of 380V. This is the three-phase three wire power supply mode. There is also a three-phase four wire system, which has a neutral wire. The relationship between them is phase voltage or 380V, and the neutral wire is 220V.
7. In this way, I learned how to read values on a multimeter and also understood some characteristics of three-phase electricity.
