Synchronous Motors The speed of a synchronous motor can be changed by varying _______ Mechanical load Field excitation Supply frequency None of the listed here Mechanical load Field excitation Supply frequency None of the listed here ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors As the load is applied to a synchronous motor, the motor takes more armature current because The rotor strengthens the rotating field causing more motor current The increased load has to take more current The back e.m.f. decreases causing an increase in motor current The rotor by shifting its phase backward causes motor to take more current The rotor strengthens the rotating field causing more motor current The increased load has to take more current The back e.m.f. decreases causing an increase in motor current The rotor by shifting its phase backward causes motor to take more current ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors In a synchronous motor it the back e.m.f. generated in the armature at noload is approximately equal to the applied voltage, then the motor is said to be fully loaded the torque generated is maximum the excitation is said to be zero per cent the excitation is said to be hundred per cent the motor is said to be fully loaded the torque generated is maximum the excitation is said to be zero per cent the excitation is said to be hundred per cent 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 over-excitation leading power factor with under-excitation lagging power factor with over-excitation no change of power factor leading power factor with over-excitation leading power factor with under-excitation lagging power factor with over-excitation no change of power factor ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors For reciprocating compressor, the synchronous motor is designed to have pull in torque of about ______ times the full load torque. 5 2 0.5 6 5 2 0.5 6 ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors For power factor correction, synchronous motors operate at normal load with minimum excitation no-load and greatly over-excited fields normal load with zero excitation no-load and under-excited fields normal load with minimum excitation no-load and greatly over-excited fields normal load with zero excitation no-load and under-excited fields ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS