Electrical Machines A cumulatively compounded dc motor delivers rated load power at rated speed. If the series field is short-circuited, then both armature current Ia and speed ωm increase both decrese Ia remains constant but ωm increase Ia increases and ωm decreses both armature current Ia and speed ωm increase both decrese Ia remains constant but ωm increase Ia increases and ωm decreses ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements : Interpoles in dc machines 1. reducearmature reaction effects in the interpolar region 2. have the same dimension as main polls 3. have their windings connected in series with the armature 4. have same number of turns as the armature 5. have the polarity same as that of the main pole ahead in a motor From these, the correct statements are 1, 3 and 5 1 and 3 1, 2 and 3 1, 2, 3 and 5 1, 3 and 5 1 and 3 1, 2 and 3 1, 2, 3 and 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines An alternator is feeding an infinite busbar. Its prime mover is suddenly shutdown. The alternator will start working as induction motor. continue to work as synchronous motor with same direction of rotation. continue to work as alternator but the direction of rotation will reverse. come to stand still. start working as induction motor. continue to work as synchronous motor with same direction of rotation. continue to work as alternator but the direction of rotation will reverse. come to stand still. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a synchronous motor when the rotor speed exceeds the synchronous speed during hunting the damper bars develop synchronous motor torque. the damper bars develop induction motor torque. negative sequence currents are generated. the damper bars develop induction generator torque. the damper bars develop synchronous motor torque. the damper bars develop induction motor torque. negative sequence currents are generated. the damper bars develop induction generator torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider a separately excited DC motor. If the field current is increased while the armature terminal voltage is held constant, then speed of the motor None of these. Decrease. Increase. Remains same. None of these. Decrease. Increase. Remains same. 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 6% and -4% 3.2% and -1.6% 4.8% and -3.2% None of these 6% and -4% 3.2% and -1.6% 4.8% and -3.2% ANSWER DOWNLOAD EXAMIANS APP
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