(a) Internal characteristic of generator. (b) External characteristic of generator. Magnetic characteristic or open circuit characteristic of generator. (d)Total characteristic of generator.
(a) armature. (b) load. field. (d) brushes.
(a) 33.3% of its output rating. 86.6% of its output rating. (c) 48.6% of its output rating. (d) 100% of its output rating.
true. b)false.
(a) To prevent mechanical vibrations. (b) To produce large flux. Because it carries the load current which is much higher than shunt field current for the same rating of d.c machines. (d) To provide strength.
(a) Because it is difficult to fabricate solid core. (b) Because laminated core provides high flux density. To avoids eddy current and hysteresis losses. (d) To increase the main flux.
(a) Back e.m.f. is equal to applied voltage. (b) Back e.m.f is equal to zero. Back e.m.f. is equal to half the applied voltage. (d) None of the above.
D.C. shunt motor. (b) D.C. series motor. (c) Cumulative compound motor. (d) None of the above.
(a) Half of the speed of the motors when connected in parallel. One-fourth of the speed of motors when connected in parallel. (c) Same as in parallel. (d) Rated speed of any one of the motors.
(a) Equal to the torque when they are connected in parallel. (b) Half of the torque when they are connected in parallel . Four times of the torque when they are connected in parallel. (d) Twice of the torque when they are connected in parallel.
(a) They are not self-starting. Initially there is no back e.m.f. and armature current is very high which is to be avoided by using high resistance starter. (c) To overcome back e.m.f.. (d) None of the above.
(a) By varying field current only. (b) By varying field current or armature resistance. (c) By varying supply voltage only. (b) or (c).
true. (b)false.
true. (b) false.
(a) Laminations of the transformer. Magnetostriction. (c) Oil of the transformer. (d) Walls of the tanks.
(a) Proportional to 1/sinθ, where θ is the angle measured in electrical degrees between the point in the question and centre of the pole. Proportional to 1/cosθ, where θ is same as defined in (a). (c) Proportional to sinθ. (d) Proportional to cosθ.
(a) Constant current device. Constant main flux device. (c) Constant voltage device. (d) Constant power device.
(a) Self-starting with zero torque. (b) Self-starting with high torque. Self-stating with small torque than rated torque. (d) None of the above.
(a) Increase proportionately. (b) Remains almost constant. (c) Increase slightly. Reduce slightly.
(a) ratings. (b) leakage reactance. (c) efficiency. per unit impedance.