Hall Ticket No Question Paper Code: AEE017
INSTITUTE OF AERONAUTICAL ENGINEERING
(Autonomous)
Four Year B.Tech III Semester End Examinations (Regular) November, 2018
Regulation: IARE R16
ELECTRICAL TECHNOLOGY
Time: 3 Hours Max Marks: 70
Answer ONE Question from each Unit
All Questions Carry Equal Marks
All parts of the question must be answered in one place only
UNIT I
1. Determine the transient response of current and voltage in R-L series circuit using differential
equations.
A coil of inductance 50 mH and resistance 5Ω is connected to a 110 DC supply. Determine
The final value of current The value of current after 4 ms The value of the voltage
across the resistor after 6 ms.
2. Brief the procedure to solve differential equations by using Laplace transforms.
A series RC circuit has a step input V applied to it. Use Laplace transforms to determine an
expression for the current i flowing in the circuit given that when time t i 0.
UNIT II
3. Explain the hybrid parameters of a two port network.
For a series connected two port network, show that the overall impedance parameter matrix is
simply the sum of impedances matrices of each individual network.
4. Derive the expressions for transmission parameters using terminal variables shown in the
Figure 1.
Figure 1
Find the Z-parameters for the two-port network shown in Figure 2.
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Figure 2
UNIT III
5. Classify the types of attenuators and briefly explain any two types of attenuators.
A symmetrical -attenuator pad has a series arm of 500
resistance and each shunt arm of 1 k

resistance. Determine The characteristic impedance The attenuation (in dB) produced by
the pad.
6. Derive the values of C and cutoff frequency of constant k low pass filter.
Design a symmetrical lattice attenuator to have characteristic impedance of 800 Ω and attenuation
of 20 dB.
UNIT IV
7. Derive the armature torque expression of a dc motor.
A 240 4-pole shunt motor has N 1500 rpm, output 15 HP, Ia 50 Ra 0.1
Ish
1A. Brush drop 1V/brush, winding wave, Z 540. Find useful torque, total torque, and
useful flux per pole, rotational losses and efficiency.
8. Explain the classification of DC generators with neat circuit diagrams.
A shunt generator supplies a 20 kW load at 200 V through cables of resistance, R 100 m
. If
the field winding resistance, Rf 50
and the armature resistance, Ra 40 m
determine
The terminal voltage The e.m.f. generated in the armature.
UNIT V
9. Derive the emf equation of the transformer.
A 200KVA, single phase transformer has an efficiency of 98% at full load. The maximum efficiency
occurs at 3/4th full load. Calculate:
i. The iron losses
ii. The copper losses at full load
iii. The efficiency at half load assuming a power factor of 0.8 at all loads.
10. Draw and explain the approximate equivalent circuit of a transformer with reference to the
primary side.
A single phase, 250/500V transformer gave the following results:
Open Circuit test: 250V, 1A, 80W (on low voltage side.)
Short circuit test: 20V, 12A, 100W (with low voltage winding short circuited)
Draw the equivalent circuit by showing all the circuit constants.
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