When a D.C. series motor is connected to A.C. supply, the power factor will be low because of high inductance of field and armature circuits.
Description : State the modification to be done in dc series motor to work satisfactorily as ac series motor. State applications of ac series motor.
Answer : Modifications are necessary in a dc series motor so that it operates satisfactorily on ac supply. The modifications are as follows: 1) AC series motor is built with a few field turns as ... and grinders 5) High speed vacuum cleaners 6) Sewing machines 7) Food processors 8) Drilling machine
Answer : If a D.C. series motor is operated on A.C. supply, it will spark excessively, have poor efficiency, have poor power factor.
Answer : The power factor of a single-phase induction motor is usually lagging.
Description : At which time power factor of the induction motor is low?
Answer : The power factor of the inducction motor is low at the time of starting as compare to while the induction motor is running.
Description : If the field of synchronous motor is under excited, power factor will be?
Answer : If the field of synchronous motor is under excited, power factor will be lagging.