27 February 2020

Difference Between Single Phase and Three Phase Induction Motor

The main key difference between single-phase and three-phase induction motor are listed below:

  • Single-phase motors are easy to repair and maintain while in three-phase induction motor maintenance difficult.
  • The efficiency of a single-phase motor is low, whereas the efficiency of the three-phase induction motor is high.
  • The starting torque of the single-phase induction motor is low, while the starting torque of the three-phase induction motor is high.
  • Single-phase motor is simple in construction, reliable and economical as compared to the three-phase induction motor.
  • The power factor of a single-phase induction motor is low as compared to that of three-phase of induction motor.
  • Single-phase motor uses single-phase supply and a three-phase induction motor uses a three-phase supply.
  • Single-phase motor is mostly used in a domestic appliance such as a mixer grinder, fans, etc while a three-phase induction motor is mostly used in the industries.
  • In the three-phase system, more current voltages drop so the distance between 2 substations is less. so we require a number of the substation while in single-phase induction we can locate the substation near a high voltage grid which runs close to main railway routes and so the initial cost of transmission reduces.
  • In the three-phase system, the 2 overhead wire is required so cost is increases compared to the single-phase system. 
  • AS the weight of the conductor is less, the supporting tower becomes higher in the single-phase system compared to the 3 phase system,.
  • Due to low current, the I2R losses are reduced, so the transmission efficiency is increased while in 3 phase system the 3.3Kv is less as compared to 25Kv so because of low voltage current is high so I2R losses are more and also a less transmission efficiency.
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