Synchronous Motors The efficiency of a properly designed synchronous motor will usually fall in range 99 to 99.5% 85 to 95% 60 to 70% 75 to 80% 99 to 99.5% 85 to 95% 60 to 70% 75 to 80% 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 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 rotor strengthens the rotating field causing more motor current The increased load has to take more 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 ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors The minimum armature current of the synchronous motor corresponds to operation at zero power factor leading 0.707 power factor lagging unity power factor 0.707 power factor leading zero power factor leading 0.707 power factor lagging unity power factor 0.707 power factor leading ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors If one phase of a 3 phase synchronous motor is short circuited, motor Will fail to pull into step Will overheat in spots Will not come upto speed Will refused ro start Will fail to pull into step Will overheat in spots Will not come upto speed Will refused ro start ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors In order to to reverse the direction of a synchronous motor, _______ Interchange any two stator lines Change supply frequency Reduce dc field excitation to zero None of the listed here Interchange any two stator lines Change supply frequency Reduce dc field excitation to zero None of the listed here ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors If the field circuit of an unloaded salientpole synchronous motor gets suddenly open-circuited, then it runs at a very high speed the motor stops it runs at a slower speed it continues to run at the same speed it runs at a very high speed the motor stops it runs at a slower speed it continues to run at the same speed ANSWER DOWNLOAD EXAMIANS APP
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