Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 4th Semester (Fourth Semester) 2015-16 409NEE Electric Machine Automatic Control Question Paper
(Following Paper ID and Roll No. to be ?lled in your
Answer Books)
RollNoJ IilIJ l I I l
B. TECH
Theory Examination (Semester-IV) 2015-16
ELECTRIC MACHlN E & AUTOMATIC CONTROL
Time : 3 Hours Max. Marks : 100
Section-A
1. Attempt ALL questions. All parts carry equal marks
(2X10=20)
(a) De?ne e?iciency and voltage regulation of transformer.
(b) What are different applications of DC motor?
(c) Draw the torque slip characteristic of 3 ? (I) induction
motor.
((1) De?ne step angle of a stepper motor. State its
signi?cance.
(e) What are the types of test signals? Give their
representation
(1) Write the analogous electrical elements in force current
analogy for linear mechanical system
(g) What are asymptotes? How will you ?nd the angle of
asymptotes?
(1L P.T.O.
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(h) De?ne PID controller.
(i) Using Routh criterion determine the stability of the
system represented by characteristic equation:
s? +8s3+16s2 +5=0-
(1) Write advantages and disadvantages of autotransformer.
Section-B
2. Attempt any FIVE of the following. (10X5=50)
(a) Explain in detail Open circuit test and Short circhit test
of a single phase transformer.
(b) How do you determine the step angle of a stepper
motor ? what are the factors to be taken into
account ?
(c) The open loop transfer function of a unity feedback
. ? K (s + 9)
transfer system IS g1ven by G(S) = S(S2 + 4s +11)
Sketch the root locus.
(d) Obtain f - v and f ? i analogous of the given system in
?g. 1. Also write the di?erential equations.
K] Lr' Bl
M1
K ? Ki
2 LFG)
M2
1?2
Fig. 1
(2)
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(e) Sketch the polar plot of the following:
(1) G
= s(1 +s)(l + 2s)
10(s + 1)
0 G =
(u) (S) s +10
(t) The open loop transfer ?mction of a unity feedback
transfer ?mction is given by.
G(s) = K
s(1 + Ts)
(1) Find by what ?ctor gain K is to be reduced so that
overshoot is reduced ?om 60% to 15%.
(i1) Find by what ?ctor gain K is to be reduced so that
damping ratio is increased ?om 0.1 to 0.6
(g) A DC series motor runs at 1000 rpm, on 220 V supply
drawing a current of 20 A. The total resistance of the
rmchine is 0.15 9. Calculate the value of extra resistance to
be connected in series with motor circuit that will reduce the
speed to 300 rpm The torque then being halfof the previous
value. Assume ?ux proportional to current.
(h) WhatisaTransforrmr?Explaindi??erenttypes oftransformers
and di?'erent losses in a transformer. How can the losses be
. . . 1?
_ (3) P.T.O.
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Section-C
Note : Attempt any TWO of the following. (15X2=30)
3. Explain in detail various methods used for speed control
of do motor.
4. What do you understand by Bode plot? What is its
importance?
Draw the Bode plot for the transfer function:
161+0.5
G(s)= 2 ( S)
s (1+0.125s)(l+0.1s)
From the graph detelmine
(i) Phase cross over ?equency
(i1) Gain cross over ?'equency
(iil) Phase Margin
(iv) Gain Margin
(v) System stability
5. (1) Discuss conversion ??om 3 phase to 2 phase using
Scott connection.
(i1) Sketch the Root Locus for the given unity feedback
system-
G(s) = _._K_____
S(S + 2)(s +1)
(4)
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This post was last modified on 29 January 2020