Difference between Synchronous and Induction motor

Electrical
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Comparison of Synchronous and Induction Motor

Synchronous Motor

Speed of Operation - For a given frequency,the speed of synchronous motor is constant irrespective of the load

Power factor based operation - Synchronous motor can be operated over a wide range of power factor,both lagging and leading

Starting requirement - Not a self starting motor

Excitation requirement - A D C excitation is required for the rotor

Cost,Simplicity and Efficiency - Costly and complex motor construction.Highly efficient for low speed drives r.p.m below 300,as their power factor can always be adjusted to 1.0

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Induction Motors

Speed of Operation - For a given frequency,the speed of induction motors falls with increase in load

Power factor based operation - Induction motors run always with a lagging power factor,which may be low at light loads.

Starting requirement - Self-Starting motor

Excitation requirement - No excitation is required for the rotor

Cost,Simplicity and Efficiency - Higher efficiency for speed above 600 r.p.m.Simple in construction and cheaper in price