Download Question Bank - Saraswathi Velu College of Engineering

5124-SARASWATHI VELU COLLEGE OF ENGINEERING
DEPARTMENT OF ELECTRONICS & COMMUNICATION ENGINEERING
QUESTION BANK
REGULATION: 2013
Subject
: ELECTRICAL ENGINEERING
SubjectCode : EE 6352
UNIT-1
D.C.MACHINES
PART-A
1.
2.
3.
4.
5.
6.
7.
8.
9.
List the main parts of DC Machine?
List the main constituents of a stator of DC Machine?
What are the functions of brushes and bearings in a DC Machine?
What is meant by excitation and methods of excitation of a DC Machine?
List the different variable and construct losses in an electrical machine?
What is the significance of back emf?
Draw the N-T and Ta-Ia characteristics of various types of DC Motor?
The outer frame of a DC Machine serves double purpose what are they?
What are the merits and demerits of swinburne’s test to predetermine the efficiency of a
DC Machine?
10. Name any two non-loading methods of testing of DC Machine?
PART-B
1. i) Describe with neat sketch the construction features of a DC Machine, stating material
uses of each component?
ii) Derive the emf equation of DC Machine, how can its direction be obtained?
2. Explain the open circuit and load characteristics of DC generators?
3. Explain the various types of DC motors with suitable diagram showing the connection of
field coils to armature?
4. i) Explain the swinburne’s test to predetermine the efficiency of a DC Machine?
ii) Explain the speed control methods of DC shunt motor?
5. A shunt machine connected to a 200v mains has a armature resistance of 0.15ohm and the
field resistance is 100ohm. Find the ratio of its speed as a generator to its speed as a
motor. The line current in each case being 75A.
UNIT-2
TRANSFORMERS
PART-A
1. What is the function of a transformer?
2. What is an Ideal transformer?
3. What are the turns ratio and transformation ratio of transformer?
4. Draw the no-load phasor diagram of transformer?
5. How does change in frequency affect the operation of a transformer?
6. Draw equivalent and approximate equivalent circuit of a transformer?
7. Define the regulation of a transformer?
8. Define transformer?
9. Write short notes on impedance test?
10. Define all-day efficiency?
PART-B
1. Explain the construction and working principle of single phase transformer?
2. Define voltage regulation. Draw the phasor diagram of lagging power factor and
determine voltage regulation?
3. Develop the equivalent and approximate equivalent circuit of transformer?
4. i) Derive the emf equation of transformer? ii) Describe the tests to determine the core loss
and full load copper loss of a single phase transformer?
5. The OC and SC tests on a 4KVA, 200/400V, 50Hz single phase transformer gave the
following results.
OC test LV side: 200V, 1A, 100W
SC test with LV side shorted: 15V, 10A, 85W.
Determine the parameters of the equivalent circuit reffered to LV side
UNIT-3
INDUCTION MOTORS
PART-A
1.
2.
3.
4.
5.
6.
7.
Draw the Y-▲starter diagram of 3 phase cage induction motor?
Draw the equivalent circuit methods of induction motor?
Name the speed control methods of induction motor?
What are the different types of starters to be used in 3 phase induction motor?
Why the slots on the induction motor are usually skewed?
Why single phase induction motor not self starting?
What are the classification of single phase induction motor based on the construction and
method of starting?
8. How can the reversal of rotation of poly phase induction motor be attained?
9. Draw the torque-slip characteristics of induction motor with increasing values of rotor
resistance?
10. In which type of motor can resistance be introduced in the rotor circuit? What is the
effect of it?
PART-B
1. i) Explain rotor resistance speed control of a 3phase induction motor?
ii) Develop the equivalent circuit of 3phase induction motor?
2. i) Draw the torque slip characteristics of an induction motor and explain different
operating modes?
ii) Explain the construction features of squirrel cage rotor and slipring rotor?
3. i) Explain double revolving field theory as applied to a single phase induction motor?
ii) Describe Kramar system of speed control for 3phase induction motor?
4. Draw the torque versus speed characteristics curve and explain the relation between
torque and slip before and after max.torque?
5. A 37.3KW, 4 pole, 50Hz induction motor has friction and winding losses of 3320W. The
stator losses equal the rotor losses. If the motor is delivering full load power output at the
speed of 1440rpm. Calculate the synchronous speed, slip, mechanical power developed
by the motor, rotor copper loss, power transferred from stator to rotor stator power input
and efficiency.
UNIT- 4
SYNCHRONOUS AND SPECIAL MACHINES
PART-A
1. Compare synchronous generator and dc generator?
2. Which type of synchronous machine is used with hydralic turblues? What is their
operating speed ranges?
3. Define Kd and Kc ?
4. Define voltage regulation of alternator?
5. What are the advantages of synchronous motor?
6. What are the different types of stepper motor?
7. Name the methods to determine voltage regulation of alternators?
8. Mention the special features on synchronous machines?
9. What are the factors that contribute reduction in terminal voltage of a loaded alternator?
10. Write some advantages of hystersis motor over induction motor?
part-b
1. i) What are the advantages of having stationary armature winding in 3phase induction
motor?
ii) Explain construction of a silent pole and smooth cylindrical synchronous machine?
2. i) Derive the emf equation of an alternator?
ii) Explain principle of operation of operation of hysteresis motor?
3. i) Describe the construction and principle of reluctance motor?
ii) Explain the construction and operation of stepper motor?
4. i) Explain in detail mmf method of obtaining the regulation of an alternator?
ii) Explain the procedure for POTIER method to calculate the voltage regulation?
5. a 600V, 600KVA single phase alternator has Ra=0.3ohm. an exciting current of 5A
produces an emf of 400V, on open circuit and an armature current of 200A on short
circuit.
(A) Calculate synchronous impedance and reactance.
(B) The full load regulation with 0.8 PF lagging.
UNIT-5
TRANSMISSION AND DISTRIBUTION
PART-A
1. Mention the advantages of EHVDC system?
2. Give the advantages of cables component to overhead transmission lines?
3. Name the types of insulators and its application?
4. What is the level of voltage for (a) generation, (b) transmission and (d) distribution
5. List the various types of cables and the operation voltage for each type?
6. Write some important advantages of dc transmission over ac transmission?
7. Name few insulting materials used in cables?
8. List the over head line insulators?
9. What is di-electric stress in a cable?
10. Mention the different types of substation?
PART-B
1. i) Discuss the type of insulators?
ii) Explain the classification of substation?
2. i) Explain the generation, transmission and distribution structure of electric power
system?
ii) Compare DC and AC transmission?
3. i) Explain the types of HVDC links?
ii) Sketch and explain suspension type insulator?
4. Draw a single line diagram showing the essential parts in a modern power system
behavior and explain the components?
5. i) explain in detail about various types of cables with diagram
ii) Write short notes on
a) Radial distribution system
b) Insulating material for cables
c) Pole-mounted substation
d) Pin type insulators