RTU 2016 Question Paper Semester VI Electronics and Communication Engineering Industrial Electronics

orlf osJ a*re

Roll No.
TotalNoofPages:
CN tr
m 6E6053
o
\o
B. Tech. Vf-Sem. (Main/Back) Exam., ApriUM ay-2016
Electronics & Communication Engineering
EI
\0 6EC3A Industrial Electronics
Common with AI, EC, EI

Time: 3 Hours
Maximum Marks: 80
Min. Passing Marks (Main & Back): 26
Instrucfions to Candidate s : -

Attempt any five questi.ons; selecting one question
from each unit. All
Questions carry equal marks. schematic diagrams must be shown
wherever necessary- Any data you
feer missing may suitabry be assumed
and stated clearly.
units of quantities used/ carcurated must be stated crearly.
use of following supporting material is permitted during
examination.
(Mentioned inform No. 205)
1. NIL
2. NIL

Q.1 (a) Describe the reverse recovery characteristics of power diode
and derive
expression of reverse recovery time.
t8l
(b) Latching current for an SCR, inserted in between
- a dc voltage source of 200V
and the load is 100mA. Compute the minimum
width of gate pulse current
required to turn on SCR in case of load consist
of _ t8l
(i) R = 20Q in series with L = 0.2H
(ii) R = 20O in series with L = 2.0H

[6E60s3] Page 1 of3
161401

q
Q'1 (a) Draw the basic structure of IGBT
and explain its working.
(b) Define the following terms l8l
_

t8l
(i) Critical rate of rise of voltage.

(ii) Finger voltage.

UNIT-II
Q'2 (a) A single phase bridge converter
is connected to RLE Load.
For continuous road
current draw the source
voltage, output voltage,
load current, source current
function of time. as a

(b) Explain the working of
single phase half wave
circuit with RL a"ra :"'j
freewheeling diode.
t6l
oR
Q.2 (a) Explain in detail three phase
converrers.
(b) Describe voltage control technique t8l
in inverter.
t8]
UNIT.III
Q'3 (a) what is class C chopper?
Explain the basic operating
principle of crass c
chopper with circuit diagram.
(b) A step up chopper has input t6l
voltage 220v & output
vortage 660v. If the non
conducting time of thyristor
chopper is r00us, compute
the pulse width. tt01
OR
Q'3 (a) Explain the circuit diagram of
switch mode power supply.
(b) Differenriate between step t10l
up & step down chopper.
t6l

[6E60s3]
Page 2 of3
I6t4ol

UNIT-IV
Q.4 (a) Define the term Dc motor. How can
we control the speed of 2-phase
induction
motors?
(b) Explain chopper control in DC t8l
series motor.
tSl
OR
Q'4 (a) Explain circuit diagram, quadrant diagram and waveforms
of singre phase half
wave converter drives.
t8l
(b) A Three phase 400v, 15kw, 1440 rpm,
50 Hzstar connected induction motor
leakage impedance of 0'4
+ J l.6Q stator impedance and rotational
losses are
assumed negrigibre. If this
motor is energized from r20
Hz400v, 3_phase source
then calculate -
(i) Motor speed at rated load t8l
(ii) The slip at which maximum Torque
occurs.

UNIT.V
Q.5 Write short note on the following _
(a) Permanent magnet stepper motor.
(b) Induction heating control. t8l
t8l
OR
Q.5 Write short note on the following _
(a) Variable reluctance stepper motor.
(b) Hybrid stepper moror. t8l
t8l

[6E60s3] Page 3 of3
[61{ol ffi