(a) Transposing any two leads from the slip rings. Transposing any two line leads. (c) None of the above
(a) true. false
(a) By reversing the leads of main winding. (b) By reversing the leads of auxiliary winding. (a) and (b) both are true. (d) None of the above
true. (b) false
true. (b) false
(a) 90 degrees out of phase. (b) In the same phase. 180 degrees out of phase. (d) None of the above
(a) To increase the field current. (b) To decrease the field current. Not to affect the current passing through HOLD ON coil even if any change in the field current takes place. (d) None of above
(a) A.C. series motor. (b) Induction motor. D.C. series motor. (d) Synchronous motor
(a) D.C. shunt motor. (b) Squirrel cage induction motor. D.C. series motor. (d) A.C. series motor
(a) Magnetic losses are equal to mechanical losses. Armature copper losses are equal to constant losses. (c) Field copper losses are equal to constant losses. (d) Stray losses are equal to copper losses
true. (b) false
(a) The effect of magnetic field set up field current. The effect of the magnetic field set up by armature current. (c) The effect of the magnetic field set up by back e.m.f. (d) None of the above
(a) Eliminate armature reaction. Bring out mechanical balance of armature. (c) Eliminate reactance voltage. (d) None of above
To avoid unequal distribution of current at the brushes there by helping to get sparkles commutation. (b) To avoid harmonics developed in the machine. (c) To avoid noise developed in the machine. (d) To avoid overhang
(a) True. false
(a) quick reversal of current in the coil under commutation. (b) Armature reaction. Reactance voltage. (d) High resistance of the brushes
(a) To neutralize the reactance voltage only. To neutralize the reactance voltage and cross-magnetizing effect of armature reaction. (c) To neutralize the cross-magnetizing effect of armature reaction only. (d) None of the above
(a) There is no need to step up the d.c. voltage. (b) Losses in the d.c. circuit are high. Faraday`s law is not valid as the rate of change of flux is zero. (d) Harmonics developed in the transformer will cause distortion in the voltage
true. (b) false
(a) true. false