Electrical Machines The brush-axis of a bipolar dc motor is rotated by 90°. The effect of this rotation on the back emf Eband the torque developed Tdwould be such that Eb is unchanged, but Td is zero Eb is zero, but Td is unchanged both Eb and Td are zero both Eb and Td are unchanged Eb is unchanged, but Td is zero Eb is zero, but Td is unchanged both Eb and Td are zero both Eb and Td are unchanged ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Induction motors normally use cast aluminium rotor because aluminium is cheaper in cost. of low resistivity. easy to cast owing to its low melting point and is easily available. lighter in weight. cheaper in cost. of low resistivity. easy to cast owing to its low melting point and is easily available. lighter in weight. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In synchronous generator a synchronous dead load (lamp, furnaces etc) has no ____________ hence it has no natural frequency of oscillation. restoring torque. mechanical rotatory system. synchronizing power co efficient. damping torque. restoring torque. mechanical rotatory system. synchronizing power co efficient. damping torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A transformer has resistance and reactance in per unit as 0.01 and 0.04 respectively. Its voltage regulation for 0.8 power factor lagging and leading will be None of these 3.2% and -1.6% 4.8% and -3.2% 6% and -4% None of these 3.2% and -1.6% 4.8% and -3.2% 6% and -4% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Slip test is performed to determine All of these positive sequence reactance and negative sequence reactance slip direct axis reactance and quadrature axis reactance All of these positive sequence reactance and negative sequence reactance slip direct axis reactance and quadrature axis reactance ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The fall in speed of the DC generator due to increase in load can be corrected by cooling the armature. increasing the input to the prime mover. increasing the excitation. reducing the load voltage. cooling the armature. increasing the input to the prime mover. increasing the excitation. reducing the load voltage. ANSWER DOWNLOAD EXAMIANS APP
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