Single-phase motor wiring

Single-phase electric motor with capacitor

A 220V motor has the same composition as a three-phase motor. However, 1 or 2 capacitors are added to imitate the third phase.

When assembling with 2 capacitors (1 permanent + 1 start), the starting torque is better (1.8 to 2.5 rated torque). The start capacitor operates for 2-3 seconds, and is then automatically disconnected for a microcontact in the motor, in order for the permanent capacitor to operate.

When making 220V single-phase motors coils, they are calculated differently than the three-phase motors, in order to include capacitors. Therefore, a 2.2 kW three-phase motor and a 2.2 kW single-phase motor have the same power, the same rated torque, but different consumptions (in amps). These consumptions are twice higher for a single-phase motor.

If you change a three-phase motor by adding capacitors, you will lose from 30% to 50% of the motor initial power.

Easi-Spare sells 220V single-phase electric motors up to 3.7kW in 3000rpm and 1500rpm.