How to distinguish between single phase and 3 phase motors.?
The only sure way to determine if a motor is a single phase or three phase motor is to look at the nameplate. Most motors have a nameplate that lists the rated voltage, current, frequency, phases and mechanical output power. You can also look for a “bump” on the side of the motor that contains a capacitor. That is a sure sign that the motor is single phase, but the motor could be single phase and not have a capacitor cover on the side. A capacitor cover does not have an opening for external wires. If you look at the motor wires and find that there are 3, 6 or 12 power wires, it is probably a 3-phase motor. If there is an even number of wires, it is probably a single phase motor. Note that some motors have wires other than the main power leads and it is sometimes very difficult to determine what all of the wires are for if there is no diagram on the motor. Three phase motors used only where three 3-power is available. Residential customers are not provided with 3-phase power. Only indus
