Synopsis of Electrical Engineering

Important multiple choice questions on Electrical Machines 1.        To eliminate the single phasing torque in an ac servomotor, the rotor must have a)       Both high resistance and reactance. b)        High resistance. c)        High reactance. d)       Large air-gap 2.        If a single-winding single-phase motor is running in a particular direction a)       Both the rotating fields (rotating in opposite directions) have the same strength. b)       Forward rotating field is slightly stronger than the backward field. c)        Forward rotating field is much stronger than the backward field. d)       Backward field is stronger than the forward field. 3.        A single-winding single phase motor has a)       Low starting torque b)       Zero starting torque c)        High starting torque d)       Starting torque equal to full-load torque 4.        A single phase stator winding when excited with ac voltage produces a)       A single rotating field r

Important Multiple Choice Questions in Electrical Machines 1.        In an electromechanical energy conversion device, the developed torque depends upon A)      Stator field strength and torque angle B)       Stator field and rotor field strengths C)       Stator field and rotor field strengths and the torque angle D)      Stator field strength only 2.        Consider the following statements: The use of interpoles in dc machines is to counteract the                                 I.             Reactance voltage                               II.             Demagnetizing effect of armature mmf in the commutating zone                             III.             Cross-magnetizing effect of armature mmf in the commutating zone Which of these statement(s) is/are correct? A)      1 &2 B)       2&3 C)       1&3 D)      3 alone 3.        The current drawn by a 220V DC motor of armature resistance 0.5 ohm and back emf 200V is A)      40A