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NEE-101/Mr.B.K.Verma, Mr.Gaurav Sharma, Ms.Kavya Mittal, Mr.Gaurav Singh, Mr. Bhupesh Kr. Pal

Date: 13/11/2013 Page-1

SHRI RAMSWAROOP MEMORIAL COLLEGE OF ENGG. & MANAGEMENT

B.Tech. [SEM I (CE,EC,EE,EN)]

QUIZ TEST-2 (Session: 2013-14)

ELECTRICAL ENGINEERING

(NEE-101)

Roll No.

(To be filled by the Student) Note: Attempt All Questions.

Part – A (Questions from Tutorial Sheet) [10 Marks]

Q1) A three phase load consist of three similar inductive coils, each of resistance 50 ohm and inductance of

0.3H. The supply is 415V, 50Hz. Calculate, (a) line current, (b) power factor and (c) total power

When load is (i) star connected (ii) delta connected. [Q- 01] [2.5+2.5] Q2) Explain the principal and operation of PMMC instrument. [Q-10] [5]

Part – B [20 Marks]

Q3) Short answer type question: (a) Define term magnetic leakage in magnetic circuit. [1]

(b)State Faraday’s law of EMI. [1]

(c) What do you understand by Variable loss in transformer? [1]

(d) What do you mean by reluctance in magnetic circuit? [1]

(e) Write down the use of 1:1 turn ratio transformer. [1]

Q4) Refer to the circuit shown and find: (i) rms current through source (ii) power factor (iii) power

dissipated. [2+1+2]

AC 141.4 sin 377t

1000 ohm 1 H

10µF2.35H

Q5) An iron bar 30 cm long and 2 cm in diameter is bent into a circular shape. It is then wound with 500 turns

of wire. Calculate the current required to produce a flux of 0.5mWb in magnetic circuit. (µr of iron= 400.)

[5]

Academic/26

Refer/WI/ACAD/18

Time: 1 Hour Max. Marks: 30


Date: 13/11/2013 Page-2

Q6) A 11000/230V, 150 KVA, single phase 50 Hz transformer has core loss of 1.4 KW and full

load copper loss of 1.6 KW. Determine

(i) KVA loading for maximum efficiency and value of maximum efficiency at unity power factor

(ii) The efficiency at 50% of full load at 0.8 power factor lagging. [3+2]

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Date: 13/11/2013 Page-1





(NEE-101)

Roll No.



Q1) A balanced three phase star connected, 210 kW load takes a leading current of 160 A when connected

across a balance three phase, 1.1 kV, 50 Hz supply. Find the load circuit parameter per phase. [Q-02] [2+3]

Q2) A permanent magnet moving coil instrument gives full scale reading of 25mA when a potential difference

across its terminal is 75mV. Show how it can be used (a) as an ammeter for a range 0-100A (b) as a

voltmeter for a range 0-75V. Also find Multiplying power of the shunt and voltage amplification.

[Q-20] [2+2+1]


Q3) Short answer type question: (a) Define term magnetic fringing in magnetic circuit. [1]

(b)Write down the importance of hysteresis loop. [1]

(c) What do you understand by Constant loss in transformer? [1]

(d) What do you mean by permeance in magnetic circuit? [1]

(e) A 11000/400V transformer has secondary resistance of 0.02 ohm, find its equivalent resistance referred

to primary side. [1]


Dissipated. [2+1+2]

AC 141.4 sin 377t

1000 ohm 1 H

10µF2.35H

Academic/26

Refer/WI/ACAD/18



Date: 13/11/2013 Page-2



[5]





-------------------X--------------------


Date: 13/11/2013 Page-1





(NEE-101)

Roll No.



Q1) A delta connected load draws a current of 15A at a lagging power factor of 0.85 from a 400V, three phase 50Hz supply. Find the resistance and inductance of each phase. [Q-03] [2+3] Q2) Describe with the diagram, the construction of a repulsion type moving iron instrument with particular

reference to the mean used for deflection, control and damping. [Q-18] [5]


Q3) Short answer type question: (a) Why transformer core are laminated? [1]

(b) Explain, why transformer does not work on dc. [1]

(c) What do you understand by iron loss in transformer? [1]

(d) What do you mean by residual magnetic flux in hysteresis loop? [1]

(e) A 22000/800V transformer has secondary resistance of 0.05 ohm, find its equivalent resistance referred

to primary side. [1]


Dissipated. [2+1+2]

AC 141.4 sin 377t

1000 ohm 1 H

10µF2.35H



[5]

Academic/26

Refer/WI/ACAD/18



Date: 13/11/2013 Page-2





-------------------X--------------------


Date: 13/11/2013 Page-1





(NEE-101)

Roll No.



Q1) Three capacitors, each of 150 µF, are connected in delta to a 400V, 3-phase 50Hz supply. What will be

capacitance of each of the three capacitors such that when connected in star across the same supply, the

line current remains the same? [Q-13] [5] Q2) A balanced three phase load consist of three coils, each having resistance of 6 ohm and inductive reactance

of 8 ohm. Determine line current and power absorbed when coils are (a) star connected (b) delta connected

across 400V, 3 phase supply. [Q-17] [2.5+2.5]


Q3) Short answer type question: (a) What factor to be considered to reduce hysteresis loss in transformer? [1]

(b) Write down tow similarities between electric and magnetic circuit. [1]

(c) What do you understand by leakage reactance in transformer? [1]

(d) What do you mean by coercive force in hysteresis loop? [1]

(e) A 11000/400V transformer has primary side resistance of 8 ohm, find its equivalent resistance referred

to secondary side. [1]


Dissipated. [2+1+2]

AC 141.4 sin 377t

1000 ohm 1 H

10µF2.35H



Academic/26

Refer/WI/ACAD/18



Date: 13/11/2013 Page-2

[5]





-------------------X--------------------


Date: 13/11/2013 Page-1





(NEE-101)

Roll No.



Q1) The power input to a 200V, 50Hz, 3 phase motor running on full load at an efficiency of 90% is measured

by two wattmeter which indicates 300kW and 100kW respectively. Find (a) The input power (b) power

factor (c) line current and power output. [Q-08] [1+2+2] Q2) Explain the different methods available for measuring power in a 3-phase load (star or delta connected).

[Q-14] [5]


Q3) Short answer type question: (a) Show the variation of transformer efficiency with load power factor. [1]

(b) Write down tow differences between electric and magnetic circuit. [1]

(c) What do you understand by winding resistance in transformer? [1]

(d) What do you mean by magnetic hysteresis? [1]

(e) Write down the condition for maximum efficiency of transformer. [1]


Dissipated. [2+1+2]

AC 141.4 sin 377t

1000 ohm 1 H

10µF2.35H



[5]

Academic/26

Refer/WI/ACAD/18



Date: 13/11/2013 Page-2





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