How to use a multimeter to determine the beginning and end of the motor
method one
① Determine the two terminals of each phase winding: Use the resistance range of a multimeter to distinguish the two terminals of each phase of the three-phase winding, and perform hypothesis numbering. Wire as shown in Figure 1-1.
②Judge the beginning and end. Pay attention to the direction in which the pointer of the multimeter (microampere setting) swings. When the switch is turned on, if the pointer swings to the side greater than 0, then the lead connected to the positive terminal of the battery and the lead connected to the negative terminal of the multimeter are the same beginning or end. If the pointer swings in the opposite direction, the lead connected to the positive terminal of the battery and the lead connected to the positive terminal of the multimeter are at the same beginning or end.
③ Then connect the battery and switch to the two wire ends of another phase and conduct a test to correctly identify the beginning and end of each phase.
Method Two
① Determine the two outlet terminals of each phase winding. Use the resistance range of a multimeter to distinguish the two wire ends of each phase of the three-phase winding.
② Assume that the windings of each phase are numbered U1, U2, V1, V2 and W1, W2.
③Judge the beginning and end. Turn the motor rotor by hand. If the pointer of the multimeter (microampere range) does not move, it proves that the assumed number is correct. If the pointer deflects, it means that the assumed number of the first and last phases of one of the phases is wrong. It should be adjusted phase by phase and retested until it is correct. until.
Low voltage AC power supply method
① Determine the two outlet terminals of each phase winding. Use the resistance range of the multimeter to distinguish the two wire ends of each phase of the three-phase winding and perform hypothesis numbering.
② Connect any two phase windings in series and then connect it to the AC voltage range of the voltmeter or multimeter, and connect the third phase winding to the 36V low-voltage AC power supply.
③Judge the beginning and end. After powering on, if the voltmeter has no reading, it means that the two wires connected together are the beginning or the end. The voltmeter has a reading. One of the two wires connected together is the head end and the other is the tail end. If any one end is known as the head end, the head and tail ends of the third phase can be determined in the same way.
