Dr. A.P.J. Abdul Kalam University MTECH I SEM (PS) Advance Course in Electrical Machines (MTPS-105) Dec 2020 Question Paper

Dr. A.P.J. Abdul Kalam University

Master of Technology

First Semester Main Examination, Dec-2020

Advance Course in Electrical Machines (MTPS-105)

Time: 3:00 Hrs ___ Max Marks 70

Note : Attempt any five questions out of eight. All questions carry equal marks.

Q.1 (a) Explain the basic reason of using transformation in electrical machines.

(b) Give the steady state and transient analysis of DC machine and obtain the

expression of speed in term of other parameter, draw its characteristics also.

Q.2 (a) Describe the steady state operation using Krons primitive model and

equivalent circuit of three phase induction motor.

(b) Derive voltage and torque equation for steady state operation of single

phase induction motor.

Q.3 (a) Obtain the transformation equation for rotating three phase winding of

synchronous machine.

(b) Derive simplified equations of a synchronous machine with two damper

coils.

Q.4 (a) Explain the construction and working principle of scharge motor.

(b) Explain how Park’s transformation transforms in a, b, c variable to d, q, o

variable?

Q.5 (a) Draw the equivalent circuit for a polyphase induction motor and state what

is represented by the various parameter involved in this circuit?

(b) Derive voltage and power equation for salient alternator using diagram.

Q.6 (a) Discuss the problems of power system analysis.

(b) Explain line to line short circuit analysis of generator.

Q.7 (a) A 3 – phase, 4 – pole, 50Hz induction motor develops an electrical torque of

7

50 Nm at a slip of 0.10 under no load, the motor is running with slip of 0.01. If a

load torque 30 Nm is suddenly applied to the motor shaft.

Find the

i) Speed as a function of time.

ii) Total inertia of motor and connected load is 6 kgm2

(b) Explain dynamic performance of three phase induction motor.

Q.8 Write short note on :- (3.5 mark each)

(a) Cross Field Commutator Machine.

(b) Scharge Motor.

(c) Application of approximate method to power system analysis.

(d) Polyphase Induction Motor

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