Download GTU BE/B.Tech 2019 Winter 3rd Sem Old 131701 Electrical Machines Question Paper

Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 3rd Sem Old 131701 Electrical Machines Previous Question Paper

1
Seat No.: ________ Enrolment No.___________

GUJARAT TECHNOLOGICAL UNIVERSITY

BE - SEMESTER ?III (Old) EXAMINATION ? WINTER 2019
Subject Code: 131701 Date: 03/12/2019

Subject Name: Electrical Machines
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) Derive an equation for induced EMF of transformer and explain significance of
transformation ratio
07
(b) Explain open-circuit and short circuit test on single phase transformer. 07

Q.2 (a) Explain condition for parallel operation of two three-phase transformers. 07
(b) Explain three-phase to two phase conversion using transformer. 07
OR
(b) Explain V-V connection of three phase transformer. 07

Q.3 (a) Explain torque-speed characteristics of three phase induction motor. 07
(b) Derive an equation for starting torque and running torque of three phase induction
motor
07
OR
Q.3 (a) Write different starter used for three phase induction motor and explain any one. 07
(b) Explain chording factor and distribution factor for alternator. 07

Q.4 (a) Draw vector diagram of loaded alternator with different power factor. 07
(b) Explain power stages and losses of three phase induction motor. 07
OR
Q.4 (a) On what bases DC generators are classified? Classify and explain DC generators. 07
(b) Write short note on Armature Reaction in DC generators. 07

Q.5 (a) Explain different characteristics of Dc shunt generator. 07
(b) Explain different methods of starting single phase induction motor. 07
OR

Q.5 (a) Explain ward-Leonard method of speed control of DC shunt motor 07
(b) Write short note on autotransformer. 07

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