Induction Motors vs Synchronous Motors-A comparison

  Induction Motors Synchronous Motors
Speed The speed varies below the synchronous speed and can be adjusted The speed is constant and rotates at the synchronous speed
Construction Simple and Rugged Construction A slightly complex construction
Starting It is self starting Special Starting Procedures are required
PF control Cannot be used for PF improvement Can be used for PF improvement
Excitation Does not require external excitation Requires DC excitation for rotor
Efficient Less Efficient More Efficient
Cost Cheaper More expensive