Start A Three Phase Motor On A Single Phase Supply


The three-phase induction motor has three winding place […]

The three-phase induction motor has three winding placed 120-degree electrical apart for producing a rotating magnetic field.

The single phase motor has running and starting winding placed 90 degrees apart to produce the rotating magnetic field.

The winding arrangement of the three-phase induction motor is required to be changed if the three-phase motor is to be used as a single phase motor.

Wire the supply across two phase wires. The motor will now hum, perhaps quite loudly. You must now turn the shaft in the direction you want, at least fast enough for it to start by itself. The motor will now be running. Unfortunately it will be hugely reduced in power.

Use a contactor with the 3 phase wires on the contacts. The coil of the contactor is operated by applying 120 volts, or smaller, single phase thus energizing the coil and closing the contacts. All across the line motor circuits utilize a single phase control circuit.