Difference between Synchronous Motor and Induction Motor

Electronics & ElectricalElectronDigital Electronics

Synchronous Motor Vs Induction Motor

The following table highlights the major points that differentiate a Synchronous Motor from an Induction Motor −

Synchronous MotorInduction Motor
It always runs at synchronous speed. Hence, it is called synchronous motor.It always runs at a speed slightly less than the synchronous speed. Thus, it is called as asynchronous motor.
A synchronous motor is a doubly excitation machine, i.e., its armature winding is connected to an AC source and its field winding is excited from a DC source.An induction motor is a singlyexcited machine, that is, its stator winding is energised from an AC source.
Its speed is independent of the load.Its speed decreases with the increase in load.
It is not self-starting. It requires external means for starting.Induction motor has self-starting torque.
The synchronous motor is more efficient than induction motor of the same ratingThe efficiency of an induction motor is lesser than that of a synchronous motor of same rating.
A synchronous motor can operate under wide range of power factors, both lagging and leading.An induction motor operates at only lagging power factor.
The power factor of a synchronous motor can be changed by changing its excitation.The power factor of induction motor cannot be controlled. It becomes very poor (lagging) at high loads.
No relative motion between the stator rotating magnetic field (RMF) and the rotor is required for the operation of a synchronous motor.For the operation of an induction motor, there must be a relative motion between the stator RMF and the rotor.
For the same rating, a synchronous motor is expensive than an induction motor.An induction motor is cheaper than a synchronous motor.
A synchronous motor has complicated construction.An induction motor have simple construction than a synchronous motor.
A synchronous motor has high starting torque as compared to an induction motor.An induction motor has less starting torque.
Synchronous motors are economical for speeds below 300 RPM.The induction motors are economical for speeds above 600 RPM.
Synchronous motors require DC excitation at the rotor.Induction motors do not require excitation for the rotor.
Applications − Driving mechanical loads at constant speed, power factor correction of electrical systems, etc.Applications − Induction motors are used for driving mechanical loads only.
Published on 28-Oct-2021 10:37:31