Electrical Machines For 250 volt DC Shunt Motor the armature and field resistance are 0.5 ohm and 250 ohm respectively. What will be the back e.m.f. produced when it takes a load current of 21A. 240 V. 280 V. 220 V. 150 V. 240 V. 280 V. 220 V. 150 V. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the increase in the torque expressed as percentage of initial torque, if current drawn by the dc series motor is increased from 10A to 11A? 11% 41% 21% 10% 11% 41% 21% 10% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements regarding the magnetization characteristics of a dc generator : 1. It represents the variation of field flux with field current. 2. Variation of open-circuit terminal voltage with field current is independent of speed 3. It is non-linear from zero to rated field current 4. It helps to determine the critical field resistance at a given speed 5. It always starts from the origin Which of these statements are correct ? 1 and 4 2, 3 and 4 1, 2 and 5 3 and 5 1 and 4 2, 3 and 4 1, 2 and 5 3 and 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A dc shunt motor has external resistance Ra and Rf in the armature and field circuits respectively. Armature current at starting can be reduced by keeping Ra maximum and Rf maximum Rf maximum and Ra minimum Ra minimum and Rf minimum Ra maximum and Rf minimum Ra maximum and Rf maximum Rf maximum and Ra minimum Ra minimum and Rf minimum Ra maximum and Rf minimum 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 will remains same. Decrease.d increase. none of these. remains same. Decrease.d increase. none of these. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following is done in speed control of DC motor by field flux control? Inserting an additional resistance in the field circuit. Inserting an additional resistance in the armature circuit. Inserting resistance to armature circuit and field circuit. Any of above. Inserting an additional resistance in the field circuit. Inserting an additional resistance in the armature circuit. Inserting resistance to armature circuit and field circuit. Any of above. ANSWER DOWNLOAD EXAMIANS APP
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