Triangular multi-branch parallel three-phase motor winding open circuit inspection circuit

For triangular (△) multi-branch parallel three-phase motors, first disassemble the winding joints. As shown in the figure, after connecting the winding into a triangle, connect one of the three terminals to the secondary of the welding machine transformer T, and connect an ammeter in series to the other end of T. After powering on, connect the needles of the ammeter in series to the other two ends of the winding respectively, and compare the measured currents. The phase with the smaller current value is the open winding.