Download GTU BE/B.Tech 2019 Winter 8th Sem Old 180901 Commissioning Of Electrical Equipments Question Paper

Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 8th Sem Old 180901 Commissioning Of Electrical Equipments Previous Question Paper

1
Seat No.: ________ Enrolment No.___________

GUJARAT TECHNOLOGICAL UNIVERSITY

BE - SEMESTER ?VIII (Old) EXAMINATION ? WINTER 2019
Subject Code: 180901 Date: 27/11/2019

Subject Name: Commissioning Of Electrical Equipments
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 Breakdown voltage (BDV) test of Transformer oil.
State properties of Transformer oil.
04
03
(b) Explain working of Lightning Arrester.
Discuss Testing & Commissioning of Lightning Arrester.
02
05

Q.2 (a) Discuss in detail Murray loop test for locating cable faults. 07
(b) Explain in brief power frequency voltage withstand test, impulse voltage
withstand test & vibration test on bus bar.
07
OR
(b) Explain Mechanical endurance and impulse testing of Circuit breakers. 07

Q.3 (a) What is Earthing? Describe factor affecting Earth Resistance. 07
(b) Explain Hopkinson?s Test of D.C. Machine. 07
OR
Q.3 (a) State importance voltage drop test.
How voltage drop test is performed on DC machine?
07
(b) Explain measurement of DC and AC Resistance of Armature and Field winding
of synchronous machines.
07

Q.4 (a) Explain Vibration and Noise measurement of synchronous machines. 07
(b) List methods of drying out of electrical equipment.
Explain any one method in detail.
02
05
OR
Q.4 (a) For the following conditions explain in detail troubles, causes and its remedies
for 3-? squirrel cage induction motor.
i) Motor fails to start ii) Motor runs at 1/7th synchronous speed. iii) Motor heats
up.
07
(b) Define: ?slip? for an Induction motor. Describe in detail method of measurement
of slip of an induction Motor.
07

Q.5 (a) Write the significance of Polarization Index Number.
Explain drying out procedure of Power Transformer.
02
05
(b) Discuss causes of troubles and failure of Transformers and their remedy. 07
OR

Q.5 (a) Differentiate between type test and routine test.
Explain any two routine test of Power transformer with circuit diagram.
03
04
(b) Explain the significance of partial discharge measurement and tan delta test in
case of transformer?
07

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