Electrical Machines The frequency of voltage generated by an alternator having 8 poles and rotating at 250 rpm is 16.67 Hz. 25 Hz. 50 Hz. 60 Hz. 16.67 Hz. 25 Hz. 50 Hz. 60 Hz. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements : For a level compounded dc generator to run at constant voltage, the series field mmf must effectively compensate 1. armature reaction mmf 2.armature resistance drop 3. brush contact voltage drop Which of these statements is/are correct ? 1 and 2 2 alone 1 and 3 1, 2 and 3 1 and 2 2 alone 1 and 3 1, 2 and 3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What will be the eddy current loss if the supply frequency of a transformer becomes double? Remains same. Four times. Eight times. Doubled. Remains same. Four times. Eight times. Doubled. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the excitation is critical, the power factor of the alternator is leading power factor. unity power factor. lagging power factor. None of these leading power factor. unity power factor. lagging power factor. None of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3-φ alternator has negligible stator resistance. A short circuit test is conducted on this alternator. At a particular speed, a field current of If1 is required to drive the rated armature current. If the speed of the alternator is reduced to half, the field current required to maintain rated armature current Would be equal to If1. Cannot be predicted due to insufficient data. Woud be equal to 2If1. Would be equal to If1/2. Would be equal to If1. Cannot be predicted due to insufficient data. Woud be equal to 2If1. Would be equal to If1/2. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In which transformer, the tertiary winding is used? Star - star Delta - star Delta - delta Star - delta Star - star Delta - star Delta - delta Star - delta ANSWER DOWNLOAD EXAMIANS APP
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