Difference between Single-phase and Threephase Induction Motor

The differences between a single-phase and a three-phase induction motor are given below −

  • A 1-phase induction motor requires single-phase AC supply, whereas a 3-phase induction motor need a source of 3-phase AC supply for its operation.

  • 1-phase induction motors produce low starting torque, whereas 3phase induction motors produce high starting torque.

  • The efficiency of a 1-phase induction motor is less as compared to a 3phase induction motor.

  • The power factor of a 1-phase induction motor is low, while the power factor of a 3-phase induction motor is high.

  • 1-phase induction motors are simple in construction, reliable and economical as compared to 3phase induction motors.

  • 1-phase induction motors are easy to repair and maintain as compared to a 3phase induction motor.

  • A 1-phase induction motor develops about 50% of the output power of that of a 3-phase induction motor for the same size and temperature rise.

  • A 1-phase induction motor is expensive than a 3phase induction motor of the same rating.

  • 1-phase induction motors are mainly used in low-power applications like small industries and domestic and commercial applications, while 3phase induction motors are used in high-power applications such as in large industries.

Comparison between Single-phase and Three-phase Induction Motor

The following table shows a summary of the differences between a single-phase induction motor and a three-phase induction motor −

ParameterSingle-Phase Induction MotorThree-Phase Induction Motor
Supply1-phase supply3-phase supply
Starting TorqueLowHigh
Power FactorLowHigh
ConstructionSimple & robustComplex & robust
Reliability & CostMore reliable & low costLess reliable & expensive
ApplicationsUsed in low power applications such as in domestic appliances.
Used in high power industrial applications.