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Seat No.: Enrolment
GUJARAT TECHNOLOGICAL UNIVERSITY
PDDC SEMESTER-II EXAMINATION WINTER 2018
Subject Code:X21101 Date: 05/01/2019
Subject Name: Electrical Engineering
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt Any five questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1

Explain construction features and working principle of DC generator.
07

Explain construction and working principle of 3-phase induction motor.
07
Q.2

Explain the types of DC motors with diagram.
07

Why 1-phase induction motor is not self start? How it make self start?
07
Q.3

Explain construction and working principle of 1-phase transformer.
07

What are the methods to control speed of DC motors. Explain in details.
07
Q.4

What are the conditions for parallel operation of alternators? Explain synchronizing of alternators.
07

Explain torque-slip characteristics of 3-phase induction motor with suitable diagram.
07
Q.5

Why starter is used in DC motor? Explain 3-point starter with figure.
07

Explain construction and working principle of synchronous motor.
07
Q.6

Discuss the characteristics of DC shunt and series motor.
07

Explain 1-phase transformer on no load and load condition with vector diagrams.
07
Q.7

Derive an equation for the e.m.f. induced in an alternator. Also derive expressions for the pitch factor and distribution factor.
07

Explain the construction and working principle of repulsion motor and universal motor.
07