Electrical Machines The residual magnetism of a self-excited dc generator is lost. To build up its emf again the armature connection must be reversed the field winding connection must be reversed the field winding must be replaced field winding must be excited by low voltage dc supply the armature connection must be reversed the field winding connection must be reversed the field winding must be replaced field winding must be excited by low voltage dc supply ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A voltmeter gives 120 oscillations per minute when connected to the rotor of an induction motor. The frequency is 50Hz. The slip of the motor is 5% 4% 25% 2% 5% 4% 25% 2% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A compound dc generator is delivering full load current at a terminal voltage of 230 V. Its series-field winding gets short circuited. If its terminal voltage 1. becomes more than 230 V, it is overcompounded generator 2. becomes more than 230 V, it is differentially compounded generator 3. becomes less than 230 V, it is overcompounded generator 4. becomes less than 230 V, it is differentially compounded generator 5. becomes less than 230 V, it is level compounded generator From these, the correct answer is 2,3 1, 4, 5 1, 4 2, 3, 5 2,3 1, 4, 5 1, 4 2, 3, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC series motor must started on no load because it would Fail to start without load. Run at dangerously high speed. Not develop starting torque. Draw more current without producing sufficient torque. Fail to start without load. Run at dangerously high speed. Not develop starting torque. Draw more current without producing sufficient torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 240 V DC series motor takes 40 A when giving its rated output at 1500 rpm. Its resistance is 0.3 ohms. The value of resistance which must be added to obtain rated torque at 1000 rpm is 2.2 ohms. 6 ohms. 1.9 ohms. 5.7 ohms. 2.2 ohms. 6 ohms. 1.9 ohms. 5.7 ohms. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In speed control of DC shunt motor by varying field flux, what may be the value of field regulator? 2 ohm. 10 ohm 0.2 ohm 100 ohm 2 ohm. 10 ohm 0.2 ohm 100 ohm ANSWER DOWNLOAD EXAMIANS APP
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