Electrical Machines What is/are the necessary conditions for voltage build up in self excited generator? Field winding resistance should be less than critical resistance. All of these Poles should contain residual flux. Field winding should be properly connected to armature winding. Field winding resistance should be less than critical resistance. All of these Poles should contain residual flux. Field winding should be properly connected to armature winding. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Copper brushes in DC machine are used in both of above cases. where high voltage and low current. None of these where low voltage and high currents are involved. in both of above cases. where high voltage and low current. None of these where low voltage and high currents are involved. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For a DC Shunt Motor having armature resistance of 0.5 Ω and 2 A armature current at no-load, when the armature current is changed to 20 A at loaded condition the speed is 1000 r.p.m. What is the speed at no-load? 1037.5 r.p.m. 1130 r.p.m. 4575.4 r.p.m. none of above. 1037.5 r.p.m. 1130 r.p.m. 4575.4 r.p.m. none of above. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements : For a level compounded dc generator to run at constant voltage, the series field mmf must effectively compensate 1. armature reaction mmf 2.armature resistance drop 3. brush contact voltage drop Which of these statements is/are correct ? 2 alone 1 and 2 1, 2 and 3 1 and 3 2 alone 1 and 2 1, 2 and 3 1 and 3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC series motor must started on no load because it would Not develop starting torque. Draw more current without producing sufficient torque. Run at dangerously high speed. Fail to start without load. Not develop starting torque. Draw more current without producing sufficient torque. Run at dangerously high speed. Fail to start without load. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In case of a DC Shunt motor if the load is decreased to some extent, what will happen to its speed? The speed will increase abruptly. The speed will remains almost constant. The speed will increase in proportion to reduction in load. The speed will increase gradually. The speed will increase abruptly. The speed will remains almost constant. The speed will increase in proportion to reduction in load. The speed will increase gradually. ANSWER DOWNLOAD EXAMIANS APP
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