SPPU Electrical Engineering (Semester 3)
Electrical Measurements and Instrumentation
December 2016
Total marks: --
Total time: --
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

Solve any one question from Q.1(a,b)& Q.2(a,b)
1(a) What are the different methods of damping used in analog indicating instruments? List their advantages and disadvantages.
6 M
1(b) Explain the construction and working of a megger with the help of a neat diagram.
6 M

2(a) Two ammeters X and Y have resistance of 1.2Ω and 1.5Ω respectively and they give full scale defelction with 15. The ammeters along with shunts are connected in parallel and then placed in a circuit in which the total current flowing 15A. Calculate the current in amperes indicated by ammeter X.
6 M
2(b) With a circuit diagram derive the equation for balance in the case of Maxwell's inductance bridge. Draw the phasor diagram for balance conditions.
6 M

Solve any one question fromQ.3(a,b)& Q.4(a,b)
3(a) When twwo wattmeters method is used for measurement of power in a three phase balanced circuit, comments upon the readings of the two wattmeters under following conditions.
i) When the power factor is unity.
ii) When the power factor is zero.
iii) When the power factor is 0.5 lagging.
6 M
3(b) A three phase, two element energy meter has a constant of 0.2 revolutions of disc per kwh. The meter is being used with a potential transformer of ration 22kV/220 V and a current transformer of ratio 100/5 A. If the line voltage is 220 V, current is 10 A, time to complete 10 revolutions is 30 seconds on unity power factor, determine the error expressed as a percentage of the correct reading.
7 M

4(a) A wattmeter reads 5.54 kW when it's current coil's connected in the red phase and it's voltage coil is connected between red phase and neutral of a symmetrical three phase system supplying a balanced load of 30A at 400 V. What will be the reading of the instrument if the connection of current coil remains unchanged and voltage coil is connected between yellow and blue phases? The phase sequence is RYB.
7 M
4(b) Explain how the following adjustments are made in a single pahse induction type energy meter.
i) Lag adjustment
ii) Adjustment for friction compensation
iii) Creep
iv) Overload compensation.
7 M

Solve any one question from Q.5(a,b) & Q.6(a,b)
5(a) Draw and explain block diagram of Digital Storage Oscilloscope.
7 M
5(b) Explain capactive transducers for pressure measurement with a neat diagram.
6 M

6(a) Describe briefly how the following measurements an be made with a neat diagram.
i) Frequency
ii) Phase angle
iii) Voltage
6 M
6(b) Explain Mcleod gauge for measurement of pressure.
7 M

Solve any one question from Q.7(a,b) Q.8(a,b)
7(a) Explain nucleanic method for level measurement with a suitable diagram.
6 M
7(b) What are the types of strain gauge? Explain foil strain gauge.
6 M

8(a) Explain hydraulic method for measurement of level.
6 M
8(b) Explain the construction and principle of working of a Linear Variable Differential Transformer (LVDT). Explain how the magnitude and direction of displacement of core an LVDT detected?
6 M

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