Electrical Machines Maximum allowable moisture content of power transformer insulating oil is generally taken as 20 ppm. 25 ppm. 45 ppm. 35 ppm. 20 ppm. 25 ppm. 45 ppm. 35 ppm. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In an alternator the voltage generated per phase is proportional to All of these number of turns in coil. flux per pole. frequency of waveform. All of these number of turns in coil. flux per pole. frequency of waveform. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a three phase star - delta transformer, what is the angle difference between primary and secondary phase voltages? Delta side leads by 30°. Star side leads by 30°. Delta side lags by -30°. Star side lags by -30°. Delta side leads by 30°. Star side leads by 30°. Delta side lags by -30°. Star side lags by -30°. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the effect of armature reaction ? Armature flux weakens the main field flux. Both option B and C. Armature flux distorts the main field flux. None of the options. Armature flux weakens the main field flux. Both option B and C. Armature flux distorts the main field flux. None of the options. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The rotor speed of an induction motor is given by Ns = 120f /p × ( 1 - r). Ns = 120f / p × ( 1 - s ). None of these Nr = 120f / p × (1-s). Ns = 120f /p × ( 1 - r). Ns = 120f / p × ( 1 - s ). None of these Nr = 120f / p × (1-s). ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is/are the necessary conditions for voltage build up in self excited generator? Poles should contain residual flux. All of these Field winding should be properly connected to armature winding. Field winding resistance should be less than critical resistance. Poles should contain residual flux. All of these Field winding should be properly connected to armature winding. Field winding resistance should be less than critical resistance. ANSWER DOWNLOAD EXAMIANS APP
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