Using a multimeter to identify the first and last ends of a motor's three-phase windings
(1) 36V AC power supply and light bulbs to identify the first and last ends
Judge the wiring as shown in the figure, judge the steps are as follows:
a. With a rocking watch or multimeter resistance gear, respectively, to find the three-phase winding of each phase of the two wire.
b. The first arbitrary to the three-phase winding of the wire were numbered U1 and U2, V1 and V2, W1 and W2, and V1, U2 connected to form a two-phase winding in series.
c. A light bulb is connected to the U1 and V2 wires.
d. W1, W2 two wires connected to the 36V AC power supply, if the light bulb is bright, that wire U1, U2 and V1, V2
The numbering is correct. If the bulb does not light up, the U1, U2 or V1, V2 in any two wire number can be adjusted.
e. And then according to the above method of W1, W2 two wire header judgement.
2) with a multimeter or microampere meter to identify the first and last ends
(1) method one
a. First of all, use the rocking meter or multimeter resistance gear, respectively, to find out the three-phase winding of each phase of the two wire head.
b. To each phase of the winding assumed number U1 and U2, V1 and V2, W1 and W2.
c. According to the wiring shown, rotate the motor rotor by hand, such as multimeter (microampere) pointer does not move, it proves that the assumption of the number is correct; if the pointer has a deflection, that is, one of the phase of the first and last end of the assumption that the number is not right. Should be adjusted phase by phase to retest, until correct.
(2) method two
a. First of all, the three-phase winding of the two phases of the line, and the phase winding terminals assumed to be U1 and U2, V1 and V2, W1 and W2.
b. Watch the direction of the multimeter (microampere file) pointer swing, close the switch instantly, if the pointer swings to the side greater than zero, then connect the positive terminal of the battery and the negative terminal of the multimeter connected to the same wire for the first or last end; such as the pointer reversed swing, then connect the positive terminal of the battery and the positive terminal of the multimeter connected to the same wire for the first or last end.
c. Then connect the battery and the switch to the other phase of the two wires, test, you can correctly identify the first and last end of each phase.
