Dr.A.P.J.Abdul Kalam University BE LATERAL III SEM ALL BRANCH Electrical Drives [EX-701] Dec - 2020 Question Papers

Dr.A.P.J.Abdul Kalam University

Bachelor of Engineering

Third Semester Main Examination, Dec-2020

Electrical Measurements and Instrumentation [EX-221]

Branch: EX

Time: 3:00 Hrs Max Marks 70

Note: 1. Attempt any five questions out of eight.

          2. All questions carry equal marks.

Q.1 (a) Define the terms-

(i) Accuracy (ii) Precision

(iii) Static sensitivity (iv) Reliability

(b) What do you mean by calibration curve? Explain loading effects due to shunt connected and series connected instruments.

Q.2 (a) Explain the construction and working of D’arsonal Galvanometer.

(b) Explain why PMMC instruments are the most widely used instruments. Discuss their advantages and disadvantages.

Q.3 (a) Explain with the help of block diagram the working of Digital voltmeter.

(b) Write down the difference between current transformer and potential transformer. Also explain their working.

Q.4 (a) Describe the constructional details and working of an electrodynamometer type of wattmeter. Discuss the main sources of errors in electrodynamometer type instruments.

(b) Explain the measurement of power using

(i) Three wattmeter method (ii) CTs and PTs

Q.5 (a) Explain the construction and operation of single phase and three phase

electronic energy meter.

(b) What is Phantom loading? Explain with example. Also describe the

testing by phantom loading for energy meters

Q.6 (a) Describe the circuit diagram of a series type ohm meter. Explain how it is

designed. Why are series type ohm meter preferred over shunt type ohm

meters?

(b) What is a B-H curve in terms of magnetic material? Write down its

characteristics?

Q.7 Write short notes on (Any Two):

(i) Lloyd fisher square method (ii) Economics of measurement system

(iii) Kelvin’s double bridge (iv) Maximum demand meter

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