DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
23041-ELECTRICAL
MACHINES II
STAFF-IN-CHARGE: N.SURESH
KUMAR
IMPORTANT QUESTIONS
UNIT-I
1. Explain the
constructional details of turbo alternator [OCT 2014] [APRIL 2015] [OCT 2015]
2.
Derive the EMF Equation of an Alternator. (12)[APRIL
2013] [OCT 2014]
3.
What are the advantages of Hydrogen cooling. (12)[OCT
2013] [APRIL 2015]
4.
Why cooling is necessary on alternators? Explain any
one method of cooling of alternator. [APRIL 2014] [OCT 2015]
5.
Explain the basic principles of salient pole type alternator with the
help of a neat diagram. (12) [OCT 2013]
6.
Explain the constructional details of stator and rotor
of a salient pole Alternator with neat diagram.[APRIL 2013]
7.
Compare the constructional features of squirrel cage salient
pole rotor with diagram (any 6 points)[APRIL 2014]
8.
Explain the methods adopted to obtain sine wave shape
of emf induced in the alternator. [OCT 2014]
UNIT-II
1.
An alternator has the following data (i) 3 phase alternator (ii) no. of
poles =8 (iii) distribution factor=.985 (iv) flux/pole=.040 Wb (v) no. of slots
on the armature=90 (vi) no. of conductor/slot=8 (vii) full pitched winding
(viii) speed of alternator=600rpm. Determine the no load terminal voltage. [OCT 2013] [APRIL
2014]
2.
Explain the synchronizing of alternator by dark lamp method.[APRIL 2013] [APRIL 2014] [OCT
2014]
3.
What are the causes of voltage drop in alternator? Draw the vector
diagram of a loaded alternator and determine the voltage regulation.[APRIL
2013]
4.
Explain load sharing of two alternator[OCT 2013]
5.
Explain the synchronizing of alternator by bright lamp method. [OCT
2015]
6.
Explain the effects of changing excitation of
alternator [OCT 2014]
7. Explain the following
i) synchronizing of alternator ii)Necessity of parallel operation of alternator
iii) Advantages of parallel operation of alternator iv)Conditions of parallel
operation of alternator [April 2015]
8. Explain Armature
reaction of an Alternator [APRIL 2015]
9. Explain the vector
diagrams of alternator for led lag and unity power factor [OCT 2015]
10. Draw neat circuit diagram and briefly explain open
circuit and short circuit test.
11. An alternator has the following data (a). Number of
phases is 3 (b)Number of slots on the Armature is 90 (c)Number of poles is10 (d)Number
of conductor per slot is 8 (e)Distribution factor is 0.965 (f)full pitched
winding (g)flux per pole is 0.040 wb (h)speed of alternator is 600 rpm (i)Connection
is star. Determine No Load Terminal voltage.
UNIT-III
1. Explain No load and
Blocked rotor test of 3 phase induction motor. [OCT 2013] [APRIL 2014]
2. Explain how rotating
magnetic field is produced in 3 phase induction motor by explaining the
principle of its operation by means of a neat diagram. [OCT 2013] [OCT 2014]
3. Compare squirrel case
and slip ring Induction Motor[APRIL 2013]
4. Explain the
construction and principle of operation of induction motor. [April 2015]
5. Explain star delta
starter with the help of the control diagram.[APRIL 2013] [APRIL 2014]
6. Auto transformer
starter [OCT 2014]
7. DOL starter [APRIL
2015]
8. Explain the speed
control of induction motor by injected emf method [OCT 2015]
9. Condition for maximum
starting torque of an induction motor
[OCT 2015]
10.
Explain Rotating
Magnetic Field produced by 3 phase 2 pole system
11.
Explain Rotor
Resistance starter with a neat diagram
UNIT-IV
1.
Explain the double field revolving theory for single
phase induction motor with neat diagram and why 1 phase induction motor not
self starting? [OCT
2013] [OCT 2014]
2.
Explain the different methods of starting of 3 phase
synchronous motor [APRIL 2014] [April 2015]
3.
Explain principle of working Split Phase Induction
Motor [APRIL 2013] [OCT 2015]
4.
Explain ‘V’ Curve and Inverted ‘V’ curve of
synchronous motor.[APRIL 2013]
5. Explain effect of
excitation on armature current and power factor of a synchronous motor. [OCT 2013]
6. Construction and
principle of operation of a synchronous motor. [OCT 2014]
7.
Single phase capacitor start induction motor [APRIL
2014]
8.
Explain capacitor Start and Run Motor with a neat
diagram [April 2015]
9.
Effect of change in excitation of synchronous motor.
[OCT 2015]
UNIT-V
1.
Explain any six points to be followed in installation
and commissioning of induction motor. [OCT 2013] [OCT 2014]
2.
Explain any one method of Oil Purification[APRIL 2013]
[OCT 2014]
3.
Write any six points for the common troubles and their
remedies for induction motor starters [APRIL 2013] [April 2015]
4.
Explain the following tests 1)Voltage test
2)continuity test 3)short circuit test [APRIL 2014] [April 2015]
5.
Working of single phase prevention relay [APRIL 2014]
6.
a)What are the transformer troubles? Explain their
causes.
b)What are the
transformer noises? Explain their remedies. [OCT 2015]
7. What are the causes
of noise and vibration of an Induction Motor [OCT 2013]
8.
Explain the causes and remedies for following motor
troubles:
i)
Motor starts in wrong direction
ii)
Motor produces excessive noise
iii)
Rotor runs at half speed
iv)
Bearings are over hot
[OCT 2015]
9. Explain Transformer Earthing and Measurement of Earth
Resistance.
***ALL THE BEST ***
