This set of Electrical Machines Multiple Choice Questions & Answers (MCQs) focuses on “Operating (or Performance) Characteristics of Induction Motors”. 1. A 10 kW, 400 V, 3-phase, 4-pole, 50 Hz induction motor develops the rated output at rated voltage with its slip rings shorted. The maximum torque equal to twice the full load torque occurs … Read more
This set of Electrical Machines Questions and Answers for Experienced people focuses on “Analysis of the Equivalent Circuit”. 1. Below is the torque slip characteristic of the induction machine. What can be inferred from it? a) R22 > R21 b) R22 < R21 c) R22 = R21 d) R22 = -R21 2. Choose the most … Read more
This set of Electrical Machines Multiple Choice Questions & Answers (MCQs) focuses on “Equivalent Circuit”. 1. Stator equivalent circuit for polyphase induction motor is? a) b) c) d) 2. The actual rotor equivalent of an induction motor is best depicted by? a) b) c) d) 3. Rc in the below circuit represents? a) core loss … Read more
This set of Electrical Machines Multiple Choice Questions & Answers (MCQs) focuses on “Induction Motor Phasor Diagram”. 1. The rotor of the slip ring induction motor is connected to an ac source and stator is short circuited. If the rotating magnetic field is rotates clockwise, the rotor rotates in _________ a) anticlockwise b) clockwise c) … Read more
This set of Electrical Machines Multiple Choice Questions & Answers (MCQs) focuses on “Losses and Efficiency”. 1. Insertion of external resistance in the squirrel cage induction motor _________ a) increases torque b) decreases torque c) increases torque for some seconds and then decreases d) does not affect 2. Insertion of external resistance in the squirrel … Read more
This set of Electrical Machines Multiple Choice Questions & Answers (MCQs) focuses on “Rotor EMF, Current and Power”. 1. Rotor leakage reactance for a three phase slip ring induction motor with slip ‘s’ is? a) s(x2) b) (x2)/s c) x2 d) (x2)(s2) 2. In an induction motor, when the number of stator slots is equal … Read more
This set of Electrical Machines Multiple Choice Questions & Answers (MCQs) focuses on “Rotor Frequency”. 1. Slip is defined as _________ (Ns as the synchronous speed and Nr is the rotor speed) a) Ns-Nr/Ns b) Ns-Nr/Nr c) Nr-Ns/Ns d) Ns-Nr 2. For a 4 pole three phase induction motor having synchronous speed of 1500 rpm … Read more
This set of Electrical Machines Questions and Answers for Campus interviews focuses on “Flux and MMF Phasors and Waves in Induction Motors”. 1. A three phase induction motor is not self starting. a) True b) False 2. Mark the correct waveform for the emf produced in an induction motor and the resultant flux density wave … Read more
This set of Electrical Machines Multiple Choice Questions & Answers (MCQs) focuses on “Principle of Operation”. 1. The rotor of a three phase induction motor can never attain synchronous speed. a) True b) False 2. The direction of rmf when a single phase supply is given to stator of three phase induction motor is? a) … Read more
This set of Electrical Machines Multiple Choice Questions & Answers (MCQs) focuses on “Induction Motor as a Transformer”. 1. An induction motor can be said analogous to _________ a) transformer b) synchronous motor c) universal motor d) stepper motor 2. A 3-phase induction motor with its rotor blocked behaves similar to a _________ a) transformer … Read more
