Electrical Machines The residual magnetism of a self-excited dc generator is lost. To build up its emf again the armature connection must be reversed field winding must be excited by low voltage dc supply the field winding connection must be reversed the field winding must be replaced the armature connection must be reversed field winding must be excited by low voltage dc supply the field winding connection must be reversed the field winding must be replaced ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When excitation is increased (over excitation), the synchronous generator operates at unity power factor. lagging power factor. leading power factor. any of the above. unity power factor. lagging power factor. leading power factor. any of the above. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Armature reaction depends on which of the following? magnitude of load current None of these both 1 and 2 power factor of load magnitude of load current None of these both 1 and 2 power factor of load ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC series motor is running with a divertor connected across its field winding. If the divertor resistance is reduced then the speed of the motor will become execessively high. increase. decrease. remain unaltered. become execessively high. increase. decrease. remain unaltered. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The rotor of a three phase induction motor has an impedance of 0.4 + j4 ohm per phase at standstill the maximum torque occurs at a slip of _____________. 15 %. 10 %. 25 %. 50 %. 15 %. 10 %. 25 %. 50 %. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The rotor power output of 3-phase induction motor is 15 KW. The rotor copper losses at a slip of 4% will be 700 W 650 W 625 W 600 W 700 W 650 W 625 W 600 W ANSWER DOWNLOAD EXAMIANS APP
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