Synchronous Motors When load on a synchronous motor is increased, its armature current is increased provided, it is ______ Over-excited All of these Under-excited Normally excited Over-excited All of these Under-excited Normally excited ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors In case one phase of a three-phase synchronous motor is short-circuited the motor will run at 2/3 of synchronous speed not start run with excessive vibrations take less than the rated load run at 2/3 of synchronous speed not start run with excessive vibrations take less than the rated load ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors In order to to reverse the direction of a synchronous motor, _______ None of the listed here Change supply frequency Interchange any two stator lines Reduce dc field excitation to zero None of the listed here Change supply frequency Interchange any two stator lines Reduce dc field excitation to zero ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors As the load is applied to a synchronous motor, the motor takes more armature current because The increased load has to take more current The back e.m.f. decreases causing an increase in motor 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 increased load has to take more current The back e.m.f. decreases causing an increase in motor 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 The efficiency of a properly designed synchronous motor will usually fall in range 99 to 99.5% 75 to 80% 85 to 95% 60 to 70% 99 to 99.5% 75 to 80% 85 to 95% 60 to 70% ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors A synchronous motor delivers reactive power when ______ None of the listed here Over excited Normally excited Under excited None of the listed here Over excited Normally excited Under excited ANSWER DOWNLOAD EXAMIANS APP
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