Download GTU BE/B.Tech 2019 Winter 7th Sem Old 170902 Electrical Machine Design I Question Paper

Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 7th Sem Old 170902 Electrical Machine Design I Previous Question Paper

1
Seat No.: ________ Enrolment No.___________

GUJARAT TECHNOLOGICAL UNIVERSITY

BE - SEMESTER ?VII (Old) EXAMINATION ? WINTER 2019
Subject Code: 170902 Date: 26/11/2019

Subject Name: Electrical Machine Design-I
Time: 10:30 AM TO 01:00 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) Discuss the factors affecting the selection of number of poles in D. C. Machine 07
(b) Derive output equation of 3 ?? core type transformer. 07

Q.2
(a)
Prepare a technical note on classification of insulating materials as per
temperature range.
07

(b)
What is design optimization? Derive necessary condition for designing a
transformer with minimum cost.
07


OR
(b) Write a Short Note on Duty Cycle. 07

Q.3
(a)
With the help of neat sketch, explain the effect of armature reaction on air gap
flux in case of D.C. machine.
07

(b) Explain diff. cooling methods used for oil immersed transformer. 07
OR
Q.3
(a) Explain Commutation in dc machine. Explain how interpole improves it. 07

(b)
Explain effect of change in frequency on losses, voltage & leakage impedance
of transformer.
07

Q.4
(a)
Estimate the leakage reactance of concentric winding in core type transformers
clearly stating the assumptions used.
07

(b) Briefly explain the principles of core design of a current transformer. 07


OR
Q.4
(a)
Discuss the factors affecting the selection of specific magnetic and specific
electric loadings in dc machine design.
07

(b) Discuss the behavior of a C.T. under system short circuit. 07

Q.5
(a) Explain steps to design shunt field winding of a D. C. machine. 07

(b)
Explain the reasons behind providing LV winding near to transformer core and
why tapings are provided on HV side.
07
OR
Q.5
(a)
What is window space factor? Explain how it varies with..
(1) kVA rating and (2) kV rating
07

(b)
Explain guidelines used for the selection of number of armature slots in D.C.
machine design.
07

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