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 Decrease.d none of these. increase. remains same. Decrease.d none of these. increase. remains same. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The polarity of a DC generator can be reversed by increasing field current. reversing field electric current as well as direction of rotation. any of above. reversing the field current. increasing field current. reversing field electric current as well as direction of rotation. any of above. reversing the field current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following are variable losses? hysteresis loss armature copper loss eddy current loss shunt field copper loss hysteresis loss armature copper loss eddy current loss shunt field copper loss ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines φA DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the speed when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 960 RPM 970 RPM 940 RPM 920 RPM 960 RPM 970 RPM 940 RPM 920 RPM ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The shaft of induction motor should be hollow. stiff. flexible. any of these. hollow. stiff. flexible. any of these. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature resistance of a permanent magnet dc motor is 0.8 Ohm. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the same source will be 88.8%. 59.2%. 57.1%. 48.0%. 88.8%. 59.2%. 57.1%. 48.0%. ANSWER DOWNLOAD EXAMIANS APP
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