Electrical Machines What is the necessity of copper brushes in a dc motors? None of these. To convert alternating supply current to direct current. To increase the flux cutting by the rotor. To absorb the mechanical shocks produced during running condition. None of these. To convert alternating supply current to direct current. To increase the flux cutting by the rotor. To absorb the mechanical shocks produced during running condition. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In which of the following, voltage regulation may be zero or negative leading power factor unity power factor lagging power factor All of these leading power factor unity power factor lagging power factor All of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the source voltage of a DC motor is increased, which of the following will decrease? Starting torque. Operating speed. Starting torque, operating speed, full load current. Full load current. Starting torque. Operating speed. Starting torque, operating speed, full load current. Full load current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 220 ,V 15 , kW 100 rpm shunt motor with armature resistance of 0.25 , W has a rated line current of 68 A and a rated field current of 2.2 A. The change in field flux required to obtain a speed of 1600 rpm while drawing a line current of 52.8 A and a field current of 1.8 A is 36.36% decrease 18.18% increase 36.36% increase 36.36% increase 36.36% decrease 18.18% increase 36.36% increase 36.36% increase ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3-phase 6 pole 50 Hz induction motor is running at 5% slip.What is the speed of the motor? 1000 rpm 900 rpm 950 rpm 850 rpm 1000 rpm 900 rpm 950 rpm 850 rpm ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines An ideal DC generated is one that has _____________ voltage regulation. positive. zero. low. negative. positive. zero. low. negative. ANSWER DOWNLOAD EXAMIANS APP
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