Difference between Synchronous motor and Induction motor
Synchronous Motor |
3Φ Induction Motor |
 By MePaJa – Own work, CC BY-SA 4.0, Link |
 By Zureks – Own work, CC BY-SA 3.0, Link |
| Synchronous motor is a doubly excited machine which requires a DC excitation at the rotor. Its stator is excited using an AC supply. | It is a singly excited machine. No excitation for the rotors. The stator windings are excited using an AC source. |
| Synchronous motor is not a self-starting motor. It is required to provide some auxiliary means to reach the synchronous speed. | An induction motor is a self-starting motor. |
| Speed of the motor remains constant. The motor speed is independent of the load. It always runs at synchronous speed from no load to full load condition. | The Speed of induction motor is always less than the synchronous speed, N < Ns. Motor speed decreases with the increase in load. |
| A synchronous motor can be made to operate from lagging power factor to leading power factor just by changing its excitation. | An induction motor operates at lagging power factor. |
| A synchronous motor is costlier than an induction motor of similar rating. | An induction motor is cheaper than the synchronous motor of similar ratings. |
| It has a complicated construction. | It is simple in construction. |
| More efficient than the induction motor. | Less efficient compared to the synchronous motor. |