Download AKTU B-Tech 4th Sem 2015-16 NEE 401 Electro Mechanical Energy Conversion Ii Question Paper

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 NEE 401 Electro Mechanical Energy Conversion Ii Question Paper

Printed Pages: 4 - NEE-401
(Following Paper ID and Roll No. to be ?lled in your
Answer Books)
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B.TECH.
Theory Examination (Semester?IV) 2015-16
ELECTRO-MECHANICAL ENERGY CONVERSION?II
Time : 3 Hours Max. Marks : 100
Section-A
1. All questions are mandatory. (10X2 = 20)
(i) What do you mean by positive and negative voltage
regulation of a synchronous alternator?
(ii) Explain the basic role of damper winding in synchro?
nous machines.
(iii) Write the main application of the three phase
synchronous motor.
(iv) What do you understand by term mechanical
vibration in a synchronous machine?
(v) Explain the equivalent circuit of a single phase
induction motor.
(1) P.T.O.
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(vi) Explain the principle of operation of a three phase induc-
tion motor.
(vil) State the terms cogging and crawling in three phase in-
duction motor.
(viii) Give various application of three phase Induction motors.
(ix) Draw the V?curve and inverted V-curve of a
synchronous motor.
(x) What are the im?portances of armature reaction in three
phase synchronous machine?
Section-B
Attempt any ?ve questions. (5X10 = 50)
(a) Exfwlain the constructional features and working prin-
ciple of the synchronous motor and develop the Torque
expression of synchronous motor.
(b) Discuss the working principle of capacitor start
capacitor run motor and also explain its equivalent
circuit.
(c) Explain the principle of operation of a universal motor.
Draw and explain its operational characteristics.
(2)
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(d)
(e)
(f)
(g)
(h)
Discuss the working principle of AC series motor.
Also explain its characteristics and applications in a
3-phase induction motor show that
Rotor cunent ??equency = slip X supply frequency
Discuss the various methods of starting of a 3-phase
induction motor.
Discuss the various methods of starting of a 3-phase
induction motor.
A 3-phase, 4-pole, 60 Hz induction motor has a slip
of 5% at no load, and 7% at ?lll load. Determine the
following :
(i) The relative speed between stator surface and
rotor ?eld.
(ii) The relative speed between stator ?eld and
rotor ?eld.
(iii) The relative speed between stator surface and
rotor surface.
State & explain the MMF method for calculation of
voltage regulation of synchronous alternator.
(3) P.T.0.
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Section-C
Attempt any two questions. (2X15 = 30)
3. State & explain forward and backward revolving ?eld
theory associated with single phase induction motors.
Also draw & explain its torque?speed characteristics.
4. State & explain two reaction theories applicable to
cylindrical synchronous machine. Also give the real
power and reactive power ?ow equations of the cy?
lindrical machine.
5. A 220V, 50 Hz, 6 pole, single phase induction motor has
the following circuit model parameters as
follows:
R1M 3.6 ohms
R2 6.8 ohms
XN+X2 15.6 ohms
X0 96 ohms
The rotational losses of the motor axe estimated to be 75
watts. At a motor of 940 rpm, determine the line current,
power factor, shaft power and e?ieiency.
_ (4)
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