Electrical Machines In a DC generator, if P be the number of poles and N be the rpm of the rotor, then frequency of magnetic reversals will be PN/2. PN/3000. PN/60. PN/120. PN/2. PN/3000. PN/60. PN/120. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 230 volt dc motor has an armature winding resistance of 0.5 ohm. Calculate the emf induced by the motor if the full load armature current is 23 ampere. 120 volt. 220.4 volt. None of these. 218.5 volt. 120 volt. 220.4 volt. None of these. 218.5 volt. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A commutator in DC machines can 1. provide half-wave rectification 2. Provide full-wave rectification 3. convert ac to dc 4. Convert dc to ac 5. provide controlled full-wave rectification From these, the correct answer is 2, 3, 4, 5 1, 2, 3 2, 3, 4 2, 3 ,5 2, 3, 4, 5 1, 2, 3 2, 3, 4 2, 3 ,5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Skewing of cage rotors offers the following advantages locking tendency is reduced. less noise. all of below. uniform torque. locking tendency is reduced. less noise. all of below. uniform torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC series motor must started on no load because it would Draw more current without producing sufficient torque. Not develop starting torque. Fail to start without load. Run at dangerously high speed. Draw more current without producing sufficient torque. Not develop starting torque. Fail to start without load. Run at dangerously high speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3-φ alternator has negligible stator resistance. A short circuit test is conducted on this alternator. At a particular speed, a field current of If1 is required to drive the rated armature current. If the speed of the alternator is reduced to half, the field current required to maintain rated armature current Would be equal to If1/2. Would be equal to If1. Cannot be predicted due to insufficient data. Woud be equal to 2If1. Would be equal to If1/2. Would be equal to If1. Cannot be predicted due to insufficient data. Woud be equal to 2If1. ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS