Electrical Machines A DC series motor is running at rated speed without any additional resistance in series. If an additional resistance is placedin series, the speed of motor Increases. Oscillates around the rated speed. Decreases. Remains unchanged. Increases. Oscillates around the rated speed. Decreases. Remains unchanged. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If starter is not used with large DC motor for starting, it will provide execessive voltage drop in line. all of above. draw a starting current many times its rated full load current. damage the armature and commutator. provide execessive voltage drop in line. all of above. draw a starting current many times its rated full load current. damage the armature and commutator. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 230 V, 50 Hz, 4 pole single phase induction motor is rotating in the clockwise ( forward ) direction at a speed of 1425 rpm. If the rotor resistance at standstill is 7.8 Ω. Then the effective rotor resistance in the backward branch of the equivalent circuit will be 4 Ω. 10 Ω. 8 Ω. 2 Ω. 4 Ω. 10 Ω. 8 Ω. 2 Ω. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Commonly used starters of cage motor is both A and B. star delta. None of these DOL. both A and B. star delta. None of these DOL. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When the armature current of 5 Amp is flowing through the dc motor the torque produced is 47 Nm. Keeping the speed constant if the armature current is increased to 7 amp, calculate the new torque. Assume losses to be constant. 38.5 Nm. 27.73 Nm . 65.8 Nm. 74 Nm. 38.5 Nm. 27.73 Nm . 65.8 Nm. 74 Nm. 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 Increase. None of these. Remains same. Decrease. Increase. None of these. Remains same. Decrease. ANSWER DOWNLOAD EXAMIANS APP
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