Download GTU BE/B.Tech 2019 Summer 5th Sem Old 150901 Electrical Machine Ii Question Paper

Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Summer 5th Sem Old 150901 Electrical Machine Ii Previous Question Paper

1
Seat No.: ________ Enrolment No.___________

GUJARAT TECHNOLOGICAL UNIVERSITY

BE - SEMESTER ? V(OLD) EXAMINATION ? SUMMER 2019
Subject Code:150901 Date:19/06/2019

Subject Name:Electrical Machine - II

Time:02:30 PM TO 05:00 PM Total Marks: 70

Instructions:

1. Attempt all questions.

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.

Q.1 (a) Explain the Parallel operation of 3-phase transformer. 07
(b) Discuss different methods of speed control of 3?phase Induction motor.

07

Q.2 (a) Explain cogging effect and crawling effect in detail.

07
(b) Explain the polarity test in 3-phase Transformer. 07
OR
(b) Why we require starters for 3- phase induction motors? Explain Auto-
transformer starter with necessary circuit diagram.

07

Q.3 (a) Describe the construction and working of a double-cage induction motor.

07
(b) Explain principle, advantages and applications of Linear Induction Motor. 07
OR
Q.3 (a) Why a 1-phase induction motor is not self starting? Explain the starting
methods for single phase induction motor in brief.
07
(b) Explain Scott connection for transformer with diagram. 07

Q.4 (a) Discuss the doubly fed induction motor with its advantages and
disadvantages.
07
(b) Explain the Sumpner?s test in 3-phase transformer. 07
OR
Q.4 (a) A squirrel cage induction motor when started by means of a star-delta starter
takes 180% of full load line current and develops 35% of full load torque at
starting. Calculate the starting torque and current in terms of full load values,
if an auto transformer with 75% tappings were employed.
07
(b) Discuss the construction, working principle and applications of shaded pole
induction motor.
07

Q.5 (a) Explain working principle, construction of Repulsion motor.

07
(b) Explain construction of welding transformer. How does it differ from power
transformer?

07
OR
Q.5 (a) Explain working principle and construction of scharge motor. 07
(b) Explain the construction, working principle and applications of induction
generator.
07

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