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Reg. No. Name:

B4B101 Pages: 2

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY

FOURTH SEMESTER B.TECH DEGREE EXAMINATION, MAY 2017

EE 202 SYNCHRONOUS AND INDUCTION MACHINES (EE)

Max. Marks: 100 Duration: 3hours

جم فح سپ و

PARTA

Answer all questions. 5 marks each.
Write any four advantages of short pitched winding in alternators.
Explain the ASA method of determining voltage regulation of alternator.
Describe how synchronisation can be achieved using a synchroscope.
Draw the phasor diagram of a three phase Induction Motor at standstill and when
operating at a Full load slip,‘s‘
What is meant by cogging in three phase Induction motor? How can it be eliminated?
Design a three step starter for a three phase,400V wound rotor Induction motor. Full Load
slip is 3% and maximum starting current is limited to full load value. Rotor resistance per
phase is 0.015 62.

. Compare the operation of Induction generator and synchronous generator.

Explain the principle of operation of Synchronous Induction motor.

PART 8
Answer any two questions.10 marks each.
Graph sheet permitted.

Derive from the fundamentals, generalised equation of the EMF generated in a non
salient pole synchronous generator, taking into account the effect of 5" and 7% harmonic
components. (10)

. Explain the effect of armature flux on main field flux when an alternator is operating at

(i) Lagging pf

(ii) Unity pf.
State the reason of accounting the effect of armature reaction as a fictitious
reactance in calculations. (10)

. A 3phase, 6000V star connected alternator has the following OCC at normal speed.

Field Ampere (A)

Terminal voltage 5000 | 6000 | 7000

With armature short circuited and full load current flowing, the field current is 17A and

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