Synchronous Motors While running, a synchronous motor is compelled to run at synchronous speed because of _______ Compulsion due to lenz's law Magnetic locking between stator and rotor poles Damper winding in its pole faces Induced emf in rotor field winding by stator flux Compulsion due to lenz's law Magnetic locking between stator and rotor poles Damper winding in its pole faces Induced emf in rotor field winding by stator flux ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors A synchronous motor connected to infinite bus-bars has at constant full load, 100% excitation and unity power factor. On changing the excitation only, the armature current will have leading power factor with under-excitation no change of power factor leading power factor with over-excitation lagging power factor with over-excitation leading power factor with under-excitation no change of power factor leading power factor with over-excitation lagging power factor with over-excitation ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as pull-out torque pull-in torque None of these pull-up torque pull-out torque pull-in torque None of these pull-up torque ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors As the load is applied to a synchronous motor, the motor takes more armature current because The back e.m.f. decreases causing an increase in motor current The increased load has to take more current The rotor strengthens the rotating field causing more motor current The rotor by shifting its phase backward causes motor to take more current The back e.m.f. decreases causing an increase in motor current The increased load has to take more current The rotor strengthens the rotating field causing more motor current The rotor by shifting its phase backward causes motor to take more current ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors Power factor of a synchronous motor is unity when The armature current is minimum None of the listed here The armature current is zero The armature current is maximum The armature current is minimum None of the listed here The armature current is zero The armature current is maximum ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors The size of a synchronous motor is determined by its _____ kW rating kVAR rating kVA rating None of the listed here kW rating kVAR rating kVA rating None of the listed here ANSWER DOWNLOAD EXAMIANS APP
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