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B.E question bank for power electronics

EE1353 – POWER ELECTRONICS

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
ACADEMIC YEAR 2010-2011 / EVEN SEMESTER
QUESTION BANK
SUBJECT CODE & NAME: EE1353 – POWER ELECTRONICS
YEAR / SEM: III/VI
UNIT-I (POWER SEMICONDUCTOR DEVICES)
PART-A
1. What are the different methods to turn on the thyristor?
2. Define latching current.
3. Define holding current.
4. What is a snubber circuit?
5. Why IGBT is very popular nowadays?
6. What is the difference between power diode and signal diode?
7. What are the advantages of GTO over SCR?
8. What losses occur in a thyristor during working conditions?
PART-B
1. Draw the two transistor model of SCR and derive an expression for anode
current. (8)
2. Explain the characteristics of SCR (8)
3. Describe the various methods of thyristor turn on. (16)
4. Explain the operation of MOSFET and IGBT (16)
UNIT II (PHASE-CONTROLLED CONVERTERS)
PART-A
1. What is the function of freewheeling diodes in controlled rectifier?
2. What is commutation angle or overlap angle?
3. What are the advantages of six pulse converter?
4. What is meant by commutation?
5. What are the types of commutation?
6. Mention some of the applications of controlled rectifier.
7. What are the different methods of firing circuits for line commutated converter?
8. What is meant by natural commutation?
9. What is meant by forced commutation? In this commutation, the current
flowing through
PART-B
EE1353 – POWER ELECTRONICS

1. Describe the working of 1 fully controlled bridge converter in the Rectifying
mode and inversion mode. And derive the expressions for average output
voltage and rms output voltage. (16)
2. Describe the working of 3 fully controlled bridge converter in the Rectifying
mode and inversion mode. And derive the expressions for average output
voltage and rms output voltage. (16)
3. Describe the working of Dual converter. (16)
4. Derive the expressions for average output voltage and rms output voltage
of 1 semiconverter. (16)
UNIT III (DC TO DC CONVERTERS)
PART-A
1. What is meant by dc chopper?
2. What are the applications of dc chopper?
3. What are the advantages of dc chopper?
4. What is meant by step-up and step-down chopper?
5. What is meant by duty-cycle?
6. What are the two types of control strategies?
7. What is meant by TRC?
8. What are the two types of TRC?
9. What is meant by PWM control in dc chopper?
PART-B
1. Describe the principle of step-up chopper. Derive an expression for the
average output voltage in terms of input dc voltage & duty cycle. (16)
2. Describe the working of four quadrant chopper. (16)
3. Explain the working of current commutated chopper with aid of circuit diagram
and necessary waveforms. Derive an expression for its output voltage. (16)
4. Explain the working of voltage commutated chopper with aid of circuit diagram
and necessary waveforms. Derive an expression for its output voltage. (16)
UNIT IV (INVERTERS)
PART-A
1. What is meant by inverter?
2. What are the applications of an inverter?
3. What are the main classification of inverter?
4. Why thyristors are not preferred for inverters?
5. Give two advantages of CSI.
6. What is meant a series inverter?
7. What is meant a parallel inverter?
8. What are the applications of a series inverter?
9. What is meant by McMurray inverter?
10. What are the applications of a CSI?
EE1353 – POWER ELECTRONICS

11. What is meant by PWM control?
12. What are the advantages of PWM control?
PART-B
1. Describe the operation of series inverter with aid of diagrams. Describe an
expression for output frequency, current and voltages. What are the
disadvantages of basic series inverter? (16)
2. State different methods of voltage control inverters. Describe about PWM
control in inverter. (16)
3. Explain the operation of 3 bridge inverter for 180 degree mode of operation
with aid of relevant phase and line voltage waveforms. (16)
UNIT V (AC VOLTAGE CONTROLLER)
PART-A
1. What does ac voltage controller mean?
2. What are the applications of ac voltage controllers?
3. What are the advantages of ac voltage controllers?
4. What are the disadvantages of ac voltage controllers?
5. What are the two methods of control in ac voltage controllers?
6. What is the difference between ON-OFF control and phase control?
7. What is meant by cyclo-converter?
8. What are the two types of cyclo-converters?
9. What is meant by step-up cyclo-converters?
10. What is meant by step-down cyclo-converters?
11. What are the applications of cyclo-converter?
PART-B
1. Explain the operation of multistage control of AC voltage controllers with neat
diagram. (16)
2. Explain the operation of 1 AC voltage controller with RL load. (16)
3. Explain the operation of 1 sinusoidal AC voltage controller. (16)
4. For a 1 voltage controller, feeding a resistive load, draw the waveforms of
source voltage, gating signals, output voltage and voltage across the SCR.
Describe the working with reference to waveforms drawn. (16)

question bank for psa

POWER SYSTEM ANALYSIS

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
POWER SYSTEM ANALYSIS
QUESTION BANK
UNIT – I THE POWER SYSTEM – AN OVERVIEW AND MODELLING
PART – A
(TWO MARK QUESTIONS)
1.
What is a single line diagram?
2.
A generator rated at 30 MVA, 11 kV has a reactance of 20%. Calculate it’s per unit reactance for a base of 50 MVA and 10 kV
3.
Define per unit value.
4.
Draw equivalent π circuit of a transformer.
5.
Write the equation for per unit impedance.
6.
Represent a short transmission line of 3 phase into its equivalent single phase circuit.
7.
Write any two advantages of per-unit representation.
8.
What is the need for system analysis in planning and operation of power system?
9.
How is generator in transient analysis represented?
10.
What are the advantages of per unit system?
11.
List the different components of power system.
12.
What is a bus?
13.
What are the approximations made in reactance diagram?
14.
How are the base values chosen in per unit representation of a power system?
15.
Write the equation converting the p.u. impedance expressed in one base to another base.
16.
What is bus impedance matrix?
17.
Define primitive matrix.
PART – B
1. Draw the reactance diagram for the power system shown in Fig.1. Neglect resistance and use a base of 100 MVA, 220 kV in 50 Ω line. The ratings of the generator, motor and transformer are given below.


POWER SYSTEM ANALYSIS
Generator: 40 MVA, 25 kV, X” = 20%
Synchronous motor : 50 MVA, 11 kV, X” = 30%
Y – Y Transformer : 40 MVA, 33/220 kV, X = 15%
Y - Δ 30 MVA, 11/220 kV, (Δ/Y), X = 15% (16)
2. Draw the structure of an electrical power system and describe the components of the system with typical values (16)
3. Obtain the per unit impedance (reactance) diagram of the power system shown in Fig.3
Fig. 3
One-line representation of a simple power system.
Generator No. 1: 30 MVA, 10.5 kV, X” = 1.6 Ohm
Generator No. 2: 15 MVA, 6.6 kV, X” = 1.2 Ohm
Generator No. 3: 25 MVA, 6.6 kV, X” = 0.56 Ohm
Transformer T1 (3phase) : 15 MVA, 33/11 kV, X = 15.2 Ohm per phase on HT side
Transformer T2 (3phase) : 15 MVA, 33/6.2 kV, X = 16 Ohm per phase on HT side
Transmission line : 20.5 Ohm/phase
Load A : 15 MW, 11kV, 0.9 p.f. lagging
Load B : 40 MW, 6.6 kV, 0.85 lagging p.f. (16)
4. Explain the modeling of generator, load, transmission line and transformer for power flow,
short circuit and stability studies. (16)
5. Choosing a common base of 20 MVA, compute the per unit impedance (reactance) of the
components of the power system shown in Fig.5 and draw the positive sequence
impedance (reactance) diagram.
Fig. 5
Gen 1 : 20 MVA, 10.5 kV, X” = 1.4 Ohm
Gen 2 : 10 MVA, 6.6 kV, X” = 1.2 Ohm
Tr 1 : 10 MVA, 33/11 kV, X = 15.2 Ohm per phase on HT side
Tr 2 : 10 MVA, 33/6.2 kV, X = 16.0 Ohm per phase on HT side
Transmission line : 22.5 Ohms per phase (16)
6. Draw the reactance diagram using base of 100 MVA, 220 kV in 50Ώ line.

POWER SYSTEM ANALYSIS
Generator : 40 MVA, 25 kV,, X” = 20%
Synchronous motor : 50 MVA, 11 kv, X” = 30%
Star-Star transformer : 40 MVA, 33/220 kV, X = 15%
Star-delta transformer : 30 MVA, 11/220 kV, X = 15%. (16)
7. (i) What are the step by step procedures to be followed to find the per-unit impedance
diagram of a power system? (4)
(ii) Draw the structure of an electrical power system and describe the components of the
system with typical values. (12)
8. Write short notes on:
(i) Single line diagram (5)
(ii) Change of base. (5)
(iii) Reactance of synchronous machines. (6)
9. A 120 MVA, 19.5 kV Generator has a synchronous reactance of 0.15 p.u and it is
connected to a transmission line through a Transformer rated 150 MVA, 230/18 kV
(star/delta) with X = 0.1 p.u.
(i)
Calculate the p.u reactance by taking generator rating as base values (5)
(ii)
Calculate the p.u reactance by taking transformer rating as base values. (5)
(iii)
Calculate the p.u reactance for a base value of 100 MVA and 220 kV on H.T side of transformer. (6)

POWER SYSTEM ANALYSIS
UNIT – II - POWER FLOW ANALYSIS
PART- A
1.
What is the information that is obtained from load flow study?
2.
Write the need for slack bus/swing bus.
3.
What are the three classes of buses of a power system used in power flow analysis? What are the quantities to be specified and to be computed for each class during power flow solution?
4.
What is a slack bus?
5.
What is meant by acceleration factor in Gauss-Seidel load flow solution and its best value?
6.
What is P-Q bus in power flow analysis?
7.
What do you mean by flat voltage start?
8.
What do you mean by an Infinite bus?
9.
What are the constraints to be satisfied to solve load flow equation for a given bus load configuration?
10. What technique is used to solve load flow problems using Zbus (Bus impedance matrix)?
11. Define load bus.
12. What are the disadvantages in reactive power compensation by shunt capacitors and how it can be overcome?
13. What is off-nominal transformer ratio?
14. What is regulating Transformer and boosting Transformer?
15. How a load flow study is performed?
16. Compare Gauss-Seidel method, Newton-Raphson method and FDPF method with respect
to number of iteration taken for convergence and memory requirements.
PART – B
1. Derive load flow algorithm using Gauss – Seidel method with flow chart and discuss the advantages of the method. (16)
2. Derive load flow algorithm using Newton-Raphson method with flow chart and state the
importance of the method. (16)
3. Explain clearly the algorithmic steps for solving load flow equation using Newton – Raphson method (polar form) when the system contains all types of buses. Assume that the generators at the P-V buses have adequate Q Limits. (16)
4. Explain the step by step procedure for the NR method of load flow studies. (16)
5. Find the bus admittance matrix for the given network. Determine the reduced admittance
matrix by eliminating node 4. The values are marked in p.u. (16)
POWER SYSTEM ANALYSIS
6. Find the bus impedance matrix for the system whose reactance diagram is shown in fig. All the impedances are in p,u. (16)
7. (i) Derive the power flow equation in polar form. (8)
(ii)Write the advantages and disadvantages of Gauss-Seidel method and
Newton-Raphson method. (8)
8.
Explain the step by step computational procedure for the Gauss-Seidel
method of load flow studies. (16)
9. The parameters of a 4-bus system are as under:
Bus code Line impedance Charging admittance
(pu) (pu)
1-2 0.2 + j 0.8 j 0.02
2-3 0.3 + j 0.9 j 0.03
2-4 0.25 +j 1.0 j 0.04
3-4 0.2 + j 0.8 j 0.02
1-3 0.1 + j0.4 j 0.01
Draw the network and find bus admittance matrix. (16)
10. Explain the step by step computational procedure for the Gauss-Seidel method of load flow studies. (16)
11. With a flow chart, explain the NR Iterative method for solving load flow problem. (16)
12. (i) Compare Gauss-Seidel method and Newton-Raphson method of load flow studies (6)
(ii) Fig.12 shows a three bus power system.
Bus 1 : Slack bus, V= 1.05/00 p.u.
Bus 2 : PV bus, V = 1.0 p.u. Pg = 3 p.u.
Bus 3 : PQ bus, Pl = 4 p.u., Ql = 2 p.u.
Carry out one iteration of load flow solution by Gauss Seidel method.
Neglect limits on reactive power generation. (10)
POWER SYSTEM ANALYSIS
UNIT – III - SYMMETRICAL FAULT ANALYSIS
PART- A
1.
Write the relative frequency of occurrence of various types of faults.
2.
Find the fault current in Fig.2, if the pre-fault voltage at the fault point is 0.97 p.u.?
Fig .2
3.
What are the assumptions made in short circuit studies of a large power system network?
4.
What are the reactance used in the analysis of symmetrical faults on the synchronous machines as its equivalent reactance?
5.
What is the reason for Transients during short circuits?
6.
Define short circuit MVA.
7.
How do short circuits occur in a power system?
8.
Mention two objectives of short circuit analysis.
9.
What is short circuit capacity of a network bus? Define the same.
10.
List the various types of shunt faults.
11.
What is the need for short circuit analysis?
PART – B
1. A generator is connected through a transformer to a synchronous motor the sub transient reactance of generator and motor are 0.15 p.u. and 0.35 p.u. respectively. The leakage reactance of the transformer is 0.1 p.u. All the reactances are calculated on a common base. A three phase fault occurs at the terminals of the motor when the terminal voltage of the generator is 0.9 p.u. The output current of generator is 1 p.u. and 0.8 p.f. leading. Find the sub transient current in p.u. in the fault, generator and motor. Use the terminal voltage of generator as reference vector. (16)
2. Explain the step by step procedure for systematic fault analysis using bus impedance matrix. (16)
3. A 60 MVA, Y connected 11 KV synchronous generator is connected to a 60 MVA, 11/132 KV Δ/Y transformer. The sub transient reactance X”d of the generator is 0.12 p.u. on a 60 MVA base, while the transformer reactance is 0.1 p.u. on the same base. The generator is unloaded when a symmetrical fault is suddenly placed at point p as shown in Fig. 3 Find the sub transient symmetrical fault current in p.u. amperes and actual amperes on both side of the transformer. Phase to neutral voltage of the generator at no load is 1.0 p.u. (16)

POWER SYSTEM ANALYSIS
Fig. 3
4. A three –phase transmission line operating at 33 KV and having a resistance and reactance of 5 Ohms and 15 Ohms respectively is connected to the generating station bus-bar through a 5000 KVA step up transformer which has a reactance of 0.05 p.u. Connected to the bus-bars are two alternators, are 10,000 KVA having 0.08 p.u. reactance and another 5000 KVA having 0.06 p.u. reactance. Calculate the KVA at a short circuit fault between phases occurring at the high voltage terminals of the transformers. (16)
5. A synchronous generator and a synchronous motor each rated 25 MVA, 11 KV having 15% sub-transient reactance are connected through transformers and a line as shown in fig. The transformers are rated 25 MVA< 11/66 KV and 66/11 KV with leakage reactance of 10% each. The line has a reactance of 10% on a base of 25 MVA, 66 Kv. The motor is drawing 15 MW at 0.5 power factor leading and a terminal voltage of 10.6 KV. When a symmetrical 3 phase fault occurs at the motor terminals. Find the sub-transient current in the generator, motor and fault. (16)
6. A three phase power of 700 MW is to be transmitted to a substation located 315 kM from the source of power. For a preliminary line design assume the following parameters:
Vs = 1.0 p.u., Vr + 0.9 p.u. ٨ = 5000 km ; zc = 320 Ώ, and Ś = 36.870 .
(i)
Based on the practical line load ability equation, determine a nominal voltage level for
the transmission line. (8)
(ii)
For the transmission voltage level obtained in (i) Calculate the theoretical maximum
power that can be transferred by the transmission line. (8)
7. A 25,000 KVA, 13.8 kV generator with X”d = 15% is connected through a transformer to a bus which supplies four identical motors as shown in Fig. 7 The sub transient reactance X”d of each motor is 20% on a base of 5000 KVA, 6.9 kV. The three-phase rating of the transformer is 25,000 KVA, 13.8/6.9 kV, with a leakage reactance of 10%. The bus voltage at the motors is 6.9 kV when a three-phase fault occurs at point p. for the fault specified, determine (i) the sub transient current in the fault (ii) the sub transient current in breaker A and (iii) the symmetrical short-circuit interrupting current in the fault and in breaker A. (16)

POWER SYSTEM ANALYSIS
Fig.7 one line diagram
8
Determine Zbus for the network shown below in Fig. 8 where the impedances labeled 1 through 6 are shown in per unit. Preserve all buses. (16)
Fig. 8
Fig. 8 Branch impedances are in p.u. and branch numbers are in parentheses.
8.
With a help of a detailed flowchart, explain how a symmetrical fault can be analyzed using
Zbus ? (16)
9.
(i) For the radial network shone below a three phase fault occurs at F. Determine the fault current and the line voltage at 11 kV bus under fault conditions. (6)

POWER SYSTEM ANALYSIS
(ii) Explain the procedure for making short-circuit studies of a large power system networks using digital computers. (10)
10.
Two synchronous machines are connected through three phase transformers to the transmission line shown in Fig.11 the ratings and reactance of the machines and transformers are
Machine 1 and 2 : 100 MVa, 20kV; X”d = X1 = X2 = 20%
X0 = 4%, Xn = 5%
Transformers T1 and T2 : 100 MVA, 20 Δ/345 YkV ; X = 8%.
On a chosen base of 100 MVA, 345 kV in the transmission line circuit the line reactances are X1 = X2 = 15% and X0 = 50%. Draw each of the three sequence networks and find the zero sequence bus impedance matrixes by means of Zbus building algorithm. (16)


POWER SYSTEM ANALYSIS
UNIT – IV - SYMMETRICAL COMPONENTS AND
UNBALANCED FAULT ANALYSIS
PART- A
1.
Draw the equivalent sequence network diagram for a single phase to ground fault in a power system.
2.
Draw the zero sequence equivalent network diagram for a 3 phase star connected alternator with reactance earthing.
3.
Write the symmetrical components of three phase system.
4.
Draw the equivalent sequence network for a Line-Line bolted fault in a power system.
5.
What is a sequence network?
6.
What are unsymmetrical faults?
7.
Draw the zero sequence network of a star-connected alternator with zero sequence impedance zgo when the neutral is grounded through an impedance zn .
8.
Draw the equivalent sequence network diagram for a single phase to ground fault in a power system.
9.
Compute the following in polar form 0120
1a
i.ja ii. 21aa
10. Draw the zero sequence diagram of a synchronous generator with neutral grounded
11. Draw the negative sequence diagram of a synchronous machine
PART- B
1.
Derive the expression for fault current in Line-to-Line fault on an unloaded generator in terms of symmetrical components. (16)
2.
Determine the fault current and MVA at faulted bus for a line to ground (solid) fault at bus 4 as shown in Fig.2
Fig.2
G1, G2 : 100 MVA, 11kV, X+ + X- = 15%, X0 = 5%, Xn = 6%
T1 T2 : 100 MVA, 11kV/220 kV, Xl\leak = 9%
L 1,L2 : X+ = X- = 10%, X0 = 10% on base of 100 MVA. Consider a fault at phase a’. (16)
POWER SYSTEM ANALYSIS
3.
A single line to ground fault occurs on bus 4 of the system shown in Fig.3
(i) Draw the sequence networks and (12)
(ii) Compute the fault current. (4)
Fig. 3
Gen 1 and 2 : 100 MVA, 20kV; X’ = X’ ’ 20% ; X0 = 4%; Xn = 5%.
Transformer 1 and 2 : 100 MVA, 20/345 KV; Xleakage = 8% on 100 MVA
Tr. Line : X’ = X’ = 15% X0 = 50% on a base of 100 MVA, 20 kV.
4.. Draw the Zero sequence diagram for the system whose one line diagram is shown in fig.
(16)
5.
Two synchronous machines are connected through three-phase transformers to the transmission line as given below in Fig. 5. The ratings and reactance of the machines and transformers are
Machines 1 and 2 : 100 MVA, 20 Kv; X”d = X 1 = X2 = 20%
X0 = 4%; Xn = 5%.
Transformers T1 and T2 : 100 Mva, 20y/345 YkV ; X= 8%
Both transformers are solidly grounded on two sides. On a chosen base of 100 MVA, 345 kV in the transmission line circuit the line reactance are X1 =X2 = 15% and X0 = 50%. The system is operating at nominal voltage without prefault currents when a bolted (Zf = o) single line-to-ground fault occurs on phase A at bus (3) Using the bus impedance matrix for each of the three sequence networks, determine the sub transient current to ground at the fault. (16)

POWER SYSTEM ANALYSIS
Fig.5
6.
Determine the positive, negative and zero sequence networks for the system shown in Fig. 6. Assume zero sequence reactance for the generator and synchronous motors as 0.06 p.u. current limiting reactors of 2.5 Ώ are connected in the neutral of the generator and motor No.2 The zero sequence reactance of the transmission line is j 300 Ώ. (10)
Fig. 6
7.
Develop the connection of sequence network when a line to line fault occurs in a power network. (16)
8.
Derive the expression for fault current in double line to ground fault on unloaded generator. Draw an equivalent network showing the inter connection of networks to simulate double line to ground fault (16)

POWER SYSTEM ANALYSIS
UNIT- V - POWER SYSTEM STABILITY
PART - A
1.
On what basis do you conclude that a given synchronous machine has lost stability
2.
Define infinite bus in a power system.
3.
What is power system stability?
4.
State equal area criterion.
5.
Write the swing equation used for stability analysis of power system.
6.
Write any two assumptions made to simplify the transient Stability problems.
7.
Write the swing-equation for a single synchronous machine connected to an infinite bus
8.
Write the concept of critical clearing angle.
9.
Define steady state stability limit.
10.
State equal area criterion.
11.
In a 3-machine system having ratings S1 S2 and S3 and inertia constants M1 M2 and M3, what is inertia constant M and H of the equivalent system?
12.
List any two methods of improving the transient stability limit of power system.
13.
Define swing curve. What is the use of swing curve?
14.
Write the power-angle equation of a synchronous machine connected to an Infinite bys and also the expression for maximum power transferable to the bus.
15.
Define critical clearing time.
PART- B
1.
Derive swing equation used for stability studies in power system. (16)
2.
Explain the modified Euler method of analyzing multi machine power system for stability with a neat flow chart. (16)
3.
(i) Derive swing equation for a synchronous machine. (8)
(ii) A 50 Hz generator is delivering 50% of the power that it is capable of delivering through a transmission line to an infinite bus. A fault occurs that increases the reactance between the generator and the infinite bus to 500% of the value before the fault. When the fault is isolated, the maximum power that can be delivered is 75% of the original maximum value. Determine the critical clearing angle for the condition described. (8)
4. Find the critical clearing angle for clearing the fault with simultaneous opening of the
breakers 1 and 2. The reactance values of various components are indicated on the
diagram. The generator is delivering 1.0 p.u. power at the instant preceding the fault. The
fault occurs at point p as shown in the figure.
(16)
5 In the system shown in Fig. 5 a three phase static capacitive reactor of reactance 1 p.u. per phase in connected through a switch at motor bus bar. Calculate the limit of steady

state power with and without reactor switch closed. Recalculate the power limit with capacitance reactor replaced by an inductive reactor of the same value. (16)
Fig.5
Assume the internal voltage of the generator to be 1.2 pu. and motor to be1.0 p.u.
6. Describe the Runge-Kutta method of solution of swing equation for multi-machine
systems. (16)
7. (i) Derive the swing equation of a synchronous machine swinging against an infinite bus. Clearly state the assumption in deducing the swing equation. (10)
(ii) The generator shown in Fig. 7 is delivering power to infinite bus. Take Vt = 1.1 p.u. Find the maximum power that can be transferred when the system is healthy. (6)
Fig. 7
9.
(i) A 2-pole 50 Hz, 11kV turbo alternator has a ratio of 100 MW, power factor 0.85
lagging. The rotor has a moment of inertia of 10,000 kgm2. Calculate H and M. (6)
(ii)A three phase fault is applied at the point P as shown below. Find the critical clearing angle for clearing the fault with simultaneous opening of the breakers 1 and 2. The reactance values of various components are indicated in the diagram. The generator is delivering 1.0 p.u. power at the instant preceding the fault. (10)
10. Describe the equal area criterion for transient stability analysis of a system. (16)

question bank for emd

EE 1352 - ELECTRICAL MACHINE DESIGN

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
ACADEMIC YEAR 2010-2011 / EVEN SEMESTER
QUESTION BANK
SUBJECT CODE & NAME: EE 1352 - ELECTRICAL MACHINE DESIGN
YEAR / SEM : III / VI
UNIT I
FUNDAMENTAL CONCEPTS
Part – A (2 MARKS)
1. What are the main dimensions of a rotating machine?
2. Define gap contraction factor for slots.
3. Define total gap contraction factor.
4. What is Carter’s Co-efficient? What is its usefulness in the design of dc machine?
5. What is the effect of salient poles on the air gap mmf?
6. Define Field form factor.
7. List the methods used for estimating the mmf for tapered teeth.
8. What is real and apparent flux density?
9. In which way the air gap length influence the design of machines?
10. What is magnetic leakage and leakage co-efficient?
11. What is fringing flux?
12. What are the differences between leakage flux and fringing flux?
13. What is magnetic circuit and what are it’s constituents.
14. Define gap contraction factor for ducts.
15. What is tooth top leakage flux?
16. What is Zig – Zag leakage flux?
17. What is skew leakage flux?
18. How will you minimize the leakage flux?
19. Define slot space factor.
20. Discuss the parameters governing the selection of conductor dimensions.
Part – B (16 MARKS)
1. a) Discuss in detail about the cooling methods adopted in transformers. (10)
b) What are the advantages of hydrogen as a better cooling medium for turbo
alternators? (6)

2. a) Discuss about the various types of thermal ratings of the electrical machines
(10)
b) Discuss about the various Insulating materials and their grades. (6)
3. a) Explain in detail about the MMF calculation for tapered Teeth. (10)
b) Discuss in detail about the real and apparent flux densities. (6)
4. a) Write about specific magnetic loading and specific electric loading. (8)
b) Explain about the cooling of Turbo alternators. (8)
5. a) What are the direct and indirect cooling methods used in electrical
machines (8)
b) Derive an equation for the slot leakage reactance (8)
6. a) Discuss in detail about the unbalance magnetic pull. (8)
b) Explain about the air gap reluctances in different types of armature slots (8)
UNIT II
DC MACHINES
Part – A (2 MARKS)
1. Define specific magnetic loading.
2. Define specific electric loading.
3. What is output equation?
4. Write the expressions for output coefficients
5. List the factors that influence the separation of D and L of a dc machine.
6. What is square pole criterion?
7. List the various L/ ratios used for separation of D and L in induction motor.
8. In a dc machine what are the limiting values of armature diameter?
9. What is un-balanced magnetic pull and how its ill-effects can be overcome?
10. What are the factors that affect the size of rotating machines?
11. What are the factors that decide the choice of specific magnetic loading?
12. .What are the factors that decide the choice of specific electric loading?
13. What is magnetization curve?
14. What are the factors that modify the reluctance of air gap
15. What are the problems encountered in estimating the mmf for teeth?
16. What factor decides the number of turns in a winding?
17. How the area of cross-section of a conductor is estimated?
18. What are the ranges of specific magnetic loading and specific electric loading in dc
machine?
19. What are the factors to be considered for the selection of number of poles in a dc
machine?
20. What are the parameters that are affected by the number of poles?
21. List the advantages and disadvantages of large number of poles.
22. Why square pole is preferred?
23. State the difference between the armature winding of dc machine and the stator
winding of ac machine.
24. Define winding pitch.
25. What is back pitch?
26. What is front pitch?
27. Define commutator pitch.
EE 1352 - ELECTRICAL MACHINE DESIGN

28. What is equalizer connection?
29. What are the factors to be considered for estimating the length of air gap in dc
machines?
30. What are the effects of armature reaction?
31. How the polarities of inter pole are decided.
32. What is the effect of interpole on main pole?
33. What is the fundamental requirement of a good insulating material?
34. What is the importance of temperature as a factor in the life of insulating
materials?
35. Why mineral insulating oils are the most widely used liquid insulation.
36. Why large size machines have large rating time constant?
37. Why ac armature winding is always made short-pitched.
38. Why equalizer connections are necessary for the armature winding of a dc machine
with lap winding.
39. Why the voltage wave form of an ac armature winding contains harmonics. ?
40. Why the conductor eddy current loss increases if embedded deeper in the slot.
Part – B (16 MARKS)
1. a) A 4 pole, 25 HP, 500 V, 600 rpm series motor has an efficiency of 82%.
The pole faces are square and the ratio of pole arc to pole pitch is 0.67.
Take Bav = 0.58 Wb/m2 and ac = 17000 amp.cond/m. Obtain the main
dimensions of the core. (12)
b) Enumerate the procedure for shunt field design (4)
2. a) A 4 pole, 400 V, 960 rpm, shunt motor has an armature of 0.3 m in diameter and
0.2 m in length. The commutator diameter is 0.22 m. Give full details of a
suitable winding including the number of slots, number of commutator segments
and number of conductors in each slot for an average flux density of
approximately 0.55wb/m2Wb / m2 in the air gap. (12)
b) Find the main dimension and number of poles of a 37 kW, 230V, 1400 rpm,
shunt motor so that a square pole face is obtained. The average gap density is
0.5 wb/m2 and the ampere conductors / meter are 22000. The ratio
of pole arc to pole pitch is 0.7 and the full load efficiency is 90% (4)
3. i) Derive the out put equation of a DC machine. (10)
ii) Distinguish between lap winding and wave winding. (6)
4. i) Determine the total commutator losses for a 1000kw, 500V, 800rpm, 10 poles
generator. Given that commutator diameter is 1.0m, current density at brush
contact =75x10-3 A/mm2 brush pressure = 14.7kv/ m2, co efficiency of
friction = 0.28, brush contact drop= 2.2V. (10)
ii) Discuss the significance of specific loadings in the design of DC machines. (6)
EE 1352 - ELECTRICAL MACHINE DESIGN

5. i) Design a suitable commutator for a 350kw, 600rpm, 440V, 6poles DC generator
having an armature diameter of 0.75m. The number of slots is 288. Assume
suitable values where it’s necessary? (10)
ii) Discuss the choice of poles and speed in DC machine. (6)
6. i) List out the procedure involved in design of shunt field winding and series field
winding? (10)
ii) Find the main dimension and number of poles of a 37 kW, 230V, 1400 rpm,
shunt generator so that a square pole face is obtained. The average gap
density is 0.7 wb/m2 and the ampere conductors / meter are 25000. The ratio of
pole arc to pole pitch is 0.7 and the full load efficiency is 90 % (6)
7. Determine the shunt field winding of a 6-pole, 440V, dc generator allowing a drop
of 15 % in the regulator. The following design date are available, mmf per pole =
7200 AT; mean length of turn = 1.2 m; winding depth = 3.5 cm; watts per sq.cm. of
cooling surface = 650. Calculate the inner, outer and end surfaces of the
cylindrical field coil for cooling. Take diameter of the insulated wire to be 0.4 mm
greater than the bare wire. Assume 2 micro – ohm / cm as the resistivity of copper
at the working temperature. (16)
8. Determine the diameter and length of armature core for a 55kW, 110V, 1000 rpm,
4 pole shunt generator, assuming specific electric and magnetic loadings of
26000 amp.cond. / m and 0.5 Wb / m2 respectively. The pole arc should be about
70% of pole pitch and length of core about 1.1 times the pole arc. Allow 10
ampere for the field current and assume a voltage drop of 4 volts for the
armature circuit. Specify the winding to be used and also determine suitable
values for the number of armature conductors and slots. (16)
UNIT III
TRANSFORMERS
Part – A (2 MARKS)
1. What is the cause of noise in transformer?
2. Why the area of yoke in a transformer is kept 15-20% more than that of core?
3. What are the salient features of a distribution transformer?
4. In transformers, why the low voltage winding is placed near the core?
5. Why circular coils are preferred in transformers?
6. What are the advantages and disadvantages of stepped cores?
7. What do you mean by stacking factor? What is its usual value?
8. What is tertiary winding?
9. List the different methods of cooling of transformers.
10. How the heat dissipation is improved by the provision of cooling tubes?
11. In mines applications transformer with oil cooling should not be used why?
12. What are the important properties of steel used in transformer core?
13. What are the advantages and disadvantages of using higher flux density in the core?
14. Why the cross section of yoke is taken greater than core section.
15. What are the types of windings, commonly used for LV winding.
16. What are the draw backs of sandwich winding?
17. Name a few insulating materials that are used in transformers.
18. How iron losses occurring in transformers can be minimized.
19. Mention clearly the condition for maximum efficiency for a transformer
20. Why the efficiency of a transformer is so high?
21. Mention the main function of cooling medium used in transformers.
Part – B (16 MARKS)
1. i) Estimate the main dimensions including winding conductor area of a 3 phase
delta-star core type transformer rated at 300KVA, 6600/400 V, 50 Hz. A suitable
core with 3 steps having a circumscribing circle of 0.25m diameter and leg spacing
of 0.4 m is available. EMF / turn = 8.5 V, = 2.5 A /mm2, kw= 0.28 and Sf = 0.9
(stacking factor) (10)
ii) Derive the output equation of a single phase transformer. (6)
2. i) Determine the main dimensions of the core, the number of turns, the cross
sectional area of conductors in primary and secondary windings of a 100 kVA, 2200
/ 480 V, 1-phase, core type transformer, to operate at a frequency of 50 Hz, by
assuming the following data. Approximate volt per turn = 7.5 volt. Maximum flux
density = 1.2 Wb / m2. ratio of effective cross – sectional area of core to square of
diameter of circumscribing circle is 0.6. Ratio of height to width of window is 2.
Window space factor = 0.28. Current density = 2.5 A/mm2. (10)
ii) Explain how to estimate the no-load current of a three phase transformer. (6)
3. i) A 250 kVA, 6600 / 400 V, 3-phase core type transformer has a total loss of 4800
watts on full load. The transformer tank is 1.25 m in height and 1 m x 0.5 m in plan.
Design a suitable scheme for cooling tubes if the average temperature rise is to be
limited to 35°C. The diameter of the tube is 50 mm and are spaced 75 mm from
each other. The average height of the tube is 1.05 m. (10)
ii) Describe about the effect of frequency on Iron losses. (6)
4. i) Derive the voltage per turn equation of a transformer. (8)
ii) Discuss about the various methods of cooling of power transformer. (8)
5. i) Determine the core and yoke dimensions for a 250 kVA, 50Hz, single phase, core
type transformer, Emf per turn = 12 V, the window space factor = 0.33, current
density = 3A / mm2 and Bmax = 1.1 T. The distance between the centers of the
square section core is twice the width of the core. (6)
ii) Calculate the dimensions of the core, the number of turns and cross sectional
area of conductors in the primary and secondary windings of a 250 kVA, 6600 / 400
V, 50 Hz, single phase shell type transformer. Ratio of magnetic to electric loadings
= 560 x 10-8, Bm = 1.1 T, = 2.5 A / mm2, Kw = 0.32, Depth of stacked core / width
of central limb = 2.6; height of window / width of window = 2.0. (10)
6. i) A 375 kVA, single phase core type transformer operating on 6.6 kV / 415V is to be
designed with approximately 7.5V per turn and a flux density of 1.1 T. Design a
suitable core section and yoke section using two sizes of stampings. The width of
smaller stampings may be approximately 0.62 times the larger stampings. State the
assumptions made. (6)
ii) The tank of a 500 kVA, 50Hz, 1-phase, core type transformer is 1.05 x 0.62 x 1.6
m high. The mean temperature rise is limited to 35°C. The loss dissipating surface
of tank is 5.34 m2. Total loss is 5325 W. Find the area of tubes and number of tubes
needed. (10)
7. The tank of 1250 kVA, natural oil cooled transformer has the dimensions length,
width and height as 0.65 x 1.55 x 1.85 m respectively. The full load loss = 13.1 kW,
loss dissipation due to radiations = 6 W / m2-°C, loss dissipation due to convection =
6.5 W / m2°C, improvement in convection due to provision of tubes = 40%,
temperature rise = 40°C, length of each tube = 1m, diameter of tube = 50mm. Find
the number of tubes for this transformer. Neglect the top and bottom surface of the
tank as regards the cooling. (16)
UNIT IV
THREE PHASE INDUCTION MOTORS
Part-A (2 marks)
1. Why does induction motor designed with high specific electric loadings have smaller
over load capacity?
2. Why the harmonic leakage flux in squirrel cage induction rotor is not present?
3. Why the length of air gap in induction motor is kept minimum possible?
4. Why do die-cast rotors is extensively used in making 3 phase cage induction motor?
5. Why do 3 phase squirrel cage induction motor finds wide application in industry?
6. What is hot spot temperature?
7. What is the advantage of having wound rotor construction?
8. What is rotating transformer?
9. What is integral slot winding and fractional slot winding?
10. What types of slots are preferred in induction motor?
11. List the undesirable effects produced by certain combination of rotor and stator slots.
12. What are the advantage and disadvantage of large air gap length in induction motor?
13. What are the factors which influence the power factor of an induction motor?
14. What are the criteria used for the choice for number of slots of an induction machine?
15. What are the factors to be considered for estimating the length of air gap in induction
motor?
16. List out the methods to improve the power factor of an induction motor?
17. Why the air gap of an induction motor is made as small as possible?
18. What happens if the air-gap of an induction motor is doubled?
19. What is the condition for obtaining the maximum torque in case of 3 phase induction
motor?
20. What are the special features of the cage rotor on induction machine?
.
Part-B (16 Marks)
1. Estimate the main dimension, air gap length, stator slots, slots / phase and cross
sectional area of stator and rotor conductors for three phase, 15HP, 400V, 6 pole,
50Hz, 975 rpm induction motor. The motor is suitable for star – delta starting. Bav
= 0.45 wb/m2. ac = 20000 AC/m. L / = 0.85. = 0.9 , P.F = 0.85. (16)
2. A 15 kW, three phase, 6 pole, 50 Hz, squirrel cage induction motor has the
following data, stator bore dia = 0.32m, axial length of stator core = 0.125 m,
number of stator slots = 54, number of conductor / stator slot = 24, current in each
stator conductor = 17.5 A, full load P.F = 0.85 lag. Design a suitable cage rotor
giving number of rotor slots section of each bar and section of each ring. The full
speed is to be 950 rpm, use copper for rotor bar and end ring conductor.
Resistivity of copper is 0.02 m. (16)
3. A 90 kW, 500V, 50 Hz, three phase, 8 pole induction motor has a star connected
stator winding accommodated is 63 slots with a 6 conductors / slot. If slip ring
voltage, an open circuit is to be about 400V at no load find suitable rotor winding.
Calculate number of rotor slots, number conductors / slot, coil span, number of
slots per pole. P.F = 0.9 and the efficiency is 0.85 (16)
4. Determine the approximate diameter and length of stator core, the number of
stator slots and the number of conductors for a 20 kW, 400V, 3 phase, 4pole,
1200rpm, delta connected induction motor. Bav =0.5T, = 0.82, ac = 26,000
amp.cond/m, power factor = 0.8, L/ = 1, double layer stator winding. (16)
5.
6. Estimate the main dimensions, air-gap length, stator slots, stator turns per phase
and cross sectional area of stator and rotor conductors for 3 phase, 110 kW,
3300V, 50 Hz, 10 poles, 600 rpm, Y connected induction motor, Bav = 0.48 Wb/m2,
ac = 28,000 amp.cond/m, L/ = 1.25, = 0.9, power factor = 0.86. (16)
7. Design a cage rotor for a 18.8HP, 3phase, 440V, 50Hz, 1000rpm, induction motor
having full load efficiency of 0.86, power factor = 0.86, D=0.25m, L=0.14m, Zss/Ss=
54. Assume missing data if any. (16)
UNIT V
SYNCHRONOUS MACHINES
Part – A (2 MARKS)
1. State three important features of turbo alternator rotors.
2. Why salient pole construction is rejected for high speed alternators.
3. What material user for the construction of turbo alternator rotor.
4. What is run-away speed?
5. What is approximately the run away speed of Kaplan turbine.
6. Write the expression for the output coefficient of synchronous machine.
7. What are the advantages of designing the alternators with higher flux density?.
8. What are the disadvantages of designing the alternators with higher gap flux density?
9. Why semi- closed slots are generally preferred for the stator of induction motors.
10. What is the effect of specific magnetic loading on the size of the machine?
11. What is the effect of specific electric loading on t he copper losses?
12. Write down the main consideration in the selection of specific loadings for the design
of induction motor.
13. What is critical speed of alternator?
14. What are the functions of damper winding?
15. What is Short Circuit Ratio (SCR)?
16 What is the effect of SCR on synchronous machine performance?
17. Why it is necessary to cool an electrical machine?
18. What is limiting factor for the diameter of synchronous machine?
19. Discuss how ventilation and cooling of a large high speed alternator is carried out.
20. Mention the factors to be considered for the design of field system in alternator.
Part – B (16 Marks)
1. Determine the main dimension for 1000 kVA, 50 Hz, three phase, 375 rpm alternator.
The average air gap flux density = 0.55 wb/m2 and ampere conductors / m = 28000.
Use rectangular pole. Assume a suitable value for L / in order that bolted on pole
construction is used for which machine permissible peripheral speed is 50 m/s. The
runway speed is 1:8 times synchronous speed. (16)
2. Find main dimension of 100 MVA, 11 kV, 50 Hz, 150 rpm, three phase water wheel
generator. The average gap density = 0.65 wb/m2 and ampere conductors / m are
40000. The peripheral speed should not exceed 65 m/s at normal running speed in
order to limit runaway peripheral speed. (16)
3. Determine suitable number of slots conductors / slot for stator winding of three phase,
3300V, 50 Hz, 300 rpm alternator, the diameter is 2.3m and axial length of core =
0.35 m. Maximum flux density in air gap should be approximately 0.9 wb / m2.
Assume sinusoidal flux distribution use single layer winding and star connection foe
stator. (16)
4. Determine for 500kVA, 6600V, 20Hz, 500 rpm and connected three phase salient
pole machine diameter, core length for square pole face number of stator slots and
number of stator conductors for double layer winding. Assume specific magnetic
loading = 0.68 tesla, ac = 30000 AC/m and Kws = 0.955. (16)
5. A 1000 kVA, 3300V, 50Hz, 300 rpm, three phase alternator has 180 slots with 5
conductors / slot ,single layer winding with full pitch coil is used. The winding is star
connected with one circuit / phase. Determine specific electric loading and magnetic
loading, IF stator core is 0.2 m and core length = 0.4 m. Using same loading
determine the data for 1250 kVA, 3300V, 50 Hz, 250 rpm, three phase star connected
alternator having 2 circuits / phase. (16)
6. Determine for a 15 MVA, 11kV, 50 Hz, 2pole, star connected turbo alternator (i) airgap
diameter, (ii) core length, (iii) number of stator conductors, from the given data
Bav= 0.55 Wb/m2, ac = 36000 amp.cond/m, = 5A/mm2, synchronous speed ns = 50
rps, Kws = 0.98, peripheral speed = 160 m/s. (16)
OTHER IMPORTANT QUESTIONS
1. Discuss the requirements of high conductivity materials.
2. Write notes on temperature gradient in conductors placed in slots, with the help of
equations
3. Writes notes on classification of insulating materials.
4. Derive the voltage per turn equation for a single phase transformer.
5. Derive an expression to find the specific slot permeance of a fully opened rectangular
slot.
6. What are the various types of synchronous machines based on rotor construction?
Bring out the constructional differences between them.
7. Discuss the effects of short circuit ratio on the performance of a synchronous machine.
8. Explain the concept of determining the temperature gradients in conductors placed in
slots
9. What are the limitations of design of electrical apparatus? Explain them.
10. Explain the various factors that affected by the selection of number of poles in DC
machines.
11. Explain the design of rotor bars and slots.
12. Explain the choice of specific magnetic and electric loadings of synchronous
machines.
13. Explain the design of induction motors using circle diagram.
14.i Discuss the factors that influence the choice of number of poles o f a dc machine
ii.Design a shunt field coil of a dc motor from the following data.
Field ampere turns/pole=9000, Mean length of turn=1.4 m, Depth of coil=35*10-3m
Voltage across field coil=40V, Receptivity of wire=0.021 ohm/m and mm2.
Thickness of insulating varnish=0.2mm, Power dissipation from total surface of the
coil <700w/m2 Check your design for power dissipation
15. i. How do you estimate the ampere turns required for an interpole with compensating
winding
ii. A 4 poles 25hp, 500V, 600rpm series motor have an efficiency of 82%. The pole
faces are square and ratio of pole arc to pole pitch is 0.67. Take Bav=0.55wb/m2
and ampere conductors are 1 7000 amp.cond/m. obtain the main dimensions of
the core and particulars of a suitable armature winding.
16. i. Derive the relation ship between real and apparent flux densities
ii Determine the mmf required for the air gap of a dc machine having open slots,
given the following particulars. Slot pitch=4.3cm; gross core length=48cm; air gap
length= 0.6cm; slot opening=2.1cm; pole arc=18cm; flux per pole=0.056wb. There
are 8 ventilating ducts each of 1.2cm wide. The data given below is applicable for
slots and ducts.
Ratio slot opening/gap length
1 2 3 3.5 4
Carter’s coefficient
0.15 0.28 0.37 0.41 0.43
17. i.. Derive the expression for temperature rise – time curve for an electrical
machine
ii. A single phase transformer is on full load for 1 ½ hrs, no load for 1 hour and
25% overload for 1 hour. Calculate the temperature rise at the end of the period if
the temperature rise s of 20oC and 35oC occur at 1 hour and 2 hours respectively
on full load. The temperature starts from cold in both the cases. Take full load
copper loss as 2.5times the core loss.
18 . i. Obtain the expression for leakage reactance of a single phase core type
transformer
ii. Calculate the no load current of a 400V, 50Hz single phase core type
transformer the of which are follow as; Length of mean magnetic path =200cm,
Gross core section=100cm2, joints equivalent to 0.1mmair gap. Maximum flux
density 0.7 tesla, specific core loss at 50 Hz and 0.7 tesla, stacking factor 0.9,
density of core material 7.5*103Kg/m3
19. i. What are the factors to be considered in the selection of magnetic and electric
loading in a 3 ph induction motor?
ii. Estimate the main dimensions, air gap length, No. of stator slots, stator
turns/phase and cross sectional area of stator conductors for a 3 phase, 20 HP,
400V, 6 pole, 50 Hz, 970 rpm induction motor suitable for a star delta starting.
Assume magnetic and electric loading as 0.45 wb/m2 and 23000 ac/m
respectively, ratio of core length to pole pitch 0.85, full load efficiency 0.88 and
power factor 0.89.
20. i. Explain the dispersion coefficient and how does it affect the performance of
induction motor.
ii. Calculate the equivalent resistance of rotor per phase referred to stator for the
following data o f a 400V, 3 phase, 4 pole, 50 Hz cage motor. Stator slots 48,
conductors per slot 30, rotor slots 53, one bar per rotor slot, length of each bar 12
cm, area of bar 0.6220cm2, mean diameter of end rings 18cm, area of ring 1.5cm2.
Full pitch winding with phase spread for stator. Specific resistance is 0.021 /m
length per mm area.
21. i. Prove that with usual notations that the KVA rating o f a synchronous generator
is given by the following relation. KVA=1.11 Kw Bav ac L Va *10-3
Where Va= peripheral speed in m/sec
ii. Design suitable values of diameter and length of a 75 MVA, 11KV, 50 Hz,
3000rpm, 3phase, star connected alternator. Also determine the value of flux,
conductor/slot, number of turns/phase and size of alternator conductor.
Given: Average gap density=0.6 Tesla, Ampere cond/m=50000, Peripheral speed
= 180 m/sec, Winding factor=0.95, Current density=6A/mm2
22. A 1250 KVA, 3 phase, 6600V salient pole alternator has the following data.
Air gap diameter= 1.6m, length of core=0.45m, number of poles=20, armature
ampere conductors per meter=28000, ratio of pole pitch=28mm, current density in
damper bars 3A/mm2. Design a suitable damper winding for the machine.

question bank mcs

EE1354 – MODERN CONTROL SYSTEMS
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
QUESTION BANK
SUBJECT CODE & NAME : EE1354-MODERN CONTROL SYSTEMS
YEAR / SEM : III / VI
UNIT – I
STATE SPACE ANALYSIS OF CONTINUOUS TIME SYSTEMS
PART – A
1. What are the drawbacks in transfer function model analysis?
2. What is State and state variable?
3. What are the advantages of state space analysis?
4. What is a state vector ?
5. Write the state model of nth order system?
6. The state model of a linear time invariant system is given by
7. What is State diagram?
8. Draw the block diagram representation of state Model ?
9. What are the advantages of state space modeling using physical variable?
10. What are phase variables?
11. Write the properties of state transition matrix.
12. Write the solution of homogeneous state equations.?
13.Write the solution of non- homogeneous state equations.?
14.What are eigen values and eigen vectors?
15.Write any two properties of eigenvalues.
16.What is similarity transformation?
17.Define controllability and observability.
18.What is pole placement by state feed back?
19. What is state observer?
20.What is the need for state observer?
21.Derive the transfer function of the following state model.
22.What are the possible state assignment for the following electrical
system?
23.What is canonical form of state model?
24.What is meant by diagonalization?
PART – B
1. (i) Define controllability and observability .Explain both of them with the help
of Kalman’s test. (8)
(ii)Determine controllability and observability of the system described by
2. (a)Clearly explain the limitations of the classical control method. Define state,
state variables and state space. (8)
(b)Develop the state model of linear system and draw the block diagram of
state model . (8)
3. (a)State the duality between controllability and observability. (8)
(b)A linear dynamical time invariant system represented by x=Ax+Bu
4. (a)Construct a state model for a system characterized by the differential
equation
(b)What are the advantages and disadvantages of state space analysis.(8)
5. (a)State and explain the observability theorem (8)
(ii)The state model of a system is given by x = A x+ B u, Y= cx
.where A= (8)
6. (8)
(ii) What are the requirements of a good physiological transducer and explain
the operation of any two types of physiological transducers with relevant
sketches? (8)
7. Draw the structure of a living cell of our body and explain in its constituents
detail. (16)
8. (i)Explain the working of Piezoelectric transducer as arterial pressure sensor.
(8)
(ii) Explain how Piezo electric transducer produces Ultrasonic waves. (8)
8.Write short notes on:
(i)Strain guage type chest transducer (8)
(ii)Transducer as respiration sensor (8)
UNIT – II
Z-TRANSFORM AND SAMPLED DATA SYSTEMS
PART – A
1. What is sampled data control system?
2. Explain the terms sampling and sampler.
3. What is meant by quantization?
4. State (shanon’s )sampling theorem
5. What is zero order hold ?.
6. What is region of convergence?
7. Define Z-transform of unit step signal?
8. Write any two properties of discrete convolution.
9. What is pulse transfer function?
10. What are the methods available for the stability analysis of sampled data
control systems.?
11. What is bilinear transformation?
PART - B
1. (i)solve the following difference equation
2 y(k) – 2 y(k-1) + y (k-2) = r(k)
y (k) = 0 for k<0 and
r(k) = {1; k= 0,1,2
{0;k<0 (8)
(ii)check if all the roots of the following characteristics equation lie with in the
circle.
Z4–1.368Z3+0.4Z2+0.08Z+0.002=0 (8)
2. (i)Explain the concept of sampling process. (6)
(ii)Draw the frequency response of Zero-order Hold (4)
(iii)Explain any two theorems on Z-transform (6)
3. (i)Draw the buffer amplifier circuit and explain its working (8)
(ii)Explain the working of a Chopper amplifier (8)
4. Explain the working of (i)EEG Recorder (ii)EMG System (16)
5. Describe in detail about the clinical significance ,lead configuration, recording
methods and waveforms of ECG. (16)
6. Describe in detail about the basic components of a biomedical system?
(16)
7. What are the electrodes used in biomedical and explain the types of
electrodes in detail with diagrams (16)
8. (i)Explain any four types of surface electrodes in detail (8)
(ii)Describe in detail the needle-electrodes and its types (8)
UNIT – III
STATE SPACE ANALYSIS OF CONTINUOUS TIME SYSTEMS
PART – A
1. Write the properties of the state transition matrix of discrete time systems.
2. Define BSR Measurement.
3. How is the blood pressure measured in the indirect method.
4. Briefly mention the uses of gas analyzers.
5. What is called Respiratory rate?
6. What is called Cardiac Output?
7. Explain the principle of sphygmomanometer
8. What are the methods involved in direct blood pressure measurement?
9. What is pH Value of Arterial blood and Venous blood?
10. Define Apnoea.
11. What is the principle of working of Electromagnetic blood flow meter?
12. What is Spiro meter?
13. Define MVV, FVC, and FRC?
14. What are the different sounds made by the heart?
PART – B
1. Explain the concept of linear observer design and pole placement by state
feedback on discrete time systems. (16)
2. Explain with relevant equations the working and measurement produce of
Plethysmograph?. (16)
3. With suitable figures explain How pH ,Pco2 ,and Po2 are measured? (16)
4. i) Explain any one method of measuring blood pressure. (8)
ii) Explain about ESR and GSR measurements (8)
5. Describe in detail a method to determine Total Lung capacity (16)
6. Draw a circuit diagram of a pH meter and explain its working details. (16)
7. i) Explain the Working principle of a electromagnetic type blood flow meter.
(8)
ii) Define Cardiac output.Discuss a technique to determine Cardiac output
(8)
8. i) Explain the Principle of operation of an Ultrasonic blood flow meter (8)
ii) Expl;ain the origin of different heart sounds. (8)
UNIT – IV
NONLINEAR SYSTEMS
PART – A
1. What are linear and nonlinear systems? Give examples.
2. How nonlinearities are introduced in the systems?
3. What are the methods available for the analysis of nonlinear system?
4. What is the principle of X-ray machine? Give the characteristics of X- Ray
radiation ?
5. What is the principle of Endoscopy?
6. Name the different types of bio-telemetry system.
7. Distinguish between Fluoroscopy and Radiography.
8. Mention the classifications of Artifact
9. What are the types of Thermography?
PART – B
1. Draw the block diagram of Computer tomography scanner and explain its
operation with emphasis on image reconstruction. (16)
2. What is an Endoscope? List the types of commonly available endoscopes.
with schematic diagram explain the working of endoscopic laser coagulator
(16)
3. Explain the working of X ray Machine? (16)
4. (i)Explain the different elements involved in Biotelemetry circuits. (8)
(ii)Explain about Patient Monitoring system (8)
5. Explain in detail about the basic principle of Thermography.With neat
diagram explain the different parts of the Thermal Imaging system. (16)
6. (i)Write the principle of NMR? (4)
(ii)Explain with block diagram the MRI (8)
(iii)Applications of MRI (4)
7. Explain the concepts of Ultrasonography and mention its types. (16)
UNIT – V
MIMO SYSTEMS
PART – A
1. What is the use of Biphasic D.C. defibrillators?
2. What is the principle of bubble oxygenetors.
3. Why do use heart – lung machine?
4. What is the purpose of Audiometer?
5. What is a pacemaker? What are the different modes of operation of Cardiac
pacemakers?
6. What are the differences between Hemodialysis and Peritonial dialysis?
7. What are the requirements for a blood pump?
8. What is meant by dialysis?
9. What is ventilator?
10. What are the drawbacks of a.c.defibrillators?
PART – B
1. (i)Give the difference between internal and external pacemaker (8)
(ii)Give short note on Double square pulse defibrillator. (8)
2. Why do we require Heart-lung machine? Draw a block diagram of it and
explain its working. (16)
3. Draw the block diagram of synchronized D.C.defibrillator and explain its
working. (16)
4. List the different types of waveforms used for stimulation of Muscle and
nerves? Draw the block diagram of a typical Electrotherapeutic stimulator and
explain. (16)
5. Write short notes on:
i) Short wave diathermy
ii) Microwave diathermy. (16)
6. Discuss different types of defibrillators with a neat sketch. (16)
7. Explain the process of dialysis with diagrams. How does this technique play a
useful role in medical field? Give a few examples and state the limitations of
this technique. (16)
8. Draw a circuit diagram of a Peripheral nerve stimulator and explain it and also
discuss the different types of stimulator waveforms. (16)
9. i) Explain the principle of working of Ventilators. (8)
ii) Explain about audiometers in bio-medical instrumentation. (8)

questions

EC1354 VLSI DESIGN
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
QUESTION BANK
SUB.NAME : VLSI DESIGN SUBJECT CODE : EC 1354
BRANCH : EEE YEAR / SEMESTER : III / VI
______________________________________________________________ _
UNIT – I
MOS TRANSISTOR THEORY AND PROCESS TECHNOLOGY
PART-A
1. What is meant by “Epitaxy”?
2. What is isolation?
3. What is the special feature of Twin-Tub process?
4. What are the various processes used in SOI?
5. What is siliside?
6. What is LDD?
7. What is LOCOS?
8. Give the advantages of IC?
9. What is Depletion mode Device?
10. Name the four generations of Integration Circuits?
11. Name the types of Integrated Circuits?
12. Give the basic process for IC fabrication.
13. What are the various steps in Silicon wafer preparation?
14. What are the advantages of Silicon-on-Insulator process?
15. What are the advantages of CMOS process?
16. What are the different MOS layers?
17. Why NMOS technology is preferred more than PMOS technology?
18. What are the different operating regions an MOS transistor?
PART-B
1. a) Explain the operation of NMOS Enhancement transistor? (8)
b) Derive the Threshold voltage for NMOS Enhancement transistor? (8)
2. a) Explain about the body effect of MOS transistors. (6)
b) Derive the design equations for MOS devices (4)
c) What do you mean by channel length modulation (6)
3. a) Explain the second order effects with their equations. (10)
b) Explain small signal AC characteristics with its design equations. (6)
4. Explain the fabrication of PMOS transistor and its substrate fabrication Process.
(16)
5. Explain different fabrication process of CMOS transistor (16)
UNIT-II
INVERTERS AND LOGIC GATES
PART-A
1. Define noise margin.
2. Define Rise Time.
3. What is body effect?
4. What is low noise margin?
5. What is stick diagram?
6. What are Lambda (O) - based design rules?
7. Define a super buffer.
8. Give the CMOS inverter DC transfer characteristics and operating regions
9. Give the various color coding used in stick diagram?
10. Define Delay time
11. Give the different symbols for transmission gate.
12. Compare between CMOS and bipolar technologies.
13. What are the static properties of complementary CMOS Gates?
14. Draw the circuit of a nMOS inverter
15. Draw the circuit of a CMOS inverter


PART-B
1. List out the layout design rule. Draw the physical layout for one basic gate and two
universal gates. (16)
2. Explain the complimentary CMOS inverter DC characteristics. (16)
3. Write short notes on:
(a) Noise Margin (10)
(b) Rise Time (3)
(c) Fall Time (3)
4. Briefly discuss about the following:
a) Pseudo-NMOS inverter (8)
b) Saturated Load inverters (4)
c) Cascade inverter (4)
5. a. Explain the concept of static and dynamic CMOS design (8)
b. Explain the construction and operation of transmission gates (8)
UNIT III
CIRCUIT CHARACTERISATION AND PERFORMANCE ESTIMATION
PART-A
1. What are the issues to be considered for circuit characterization and performance
estimation?
2. Give the formula for resistance of a uniform slab of conducting material.
3. What are the factors to be considered for calculating total load capacitance on the
output of a CMOS gate?
4. What are the components of Power dissipation?
5. What is meant by path electrical effort?
6. Define crosstalk.
7. Define scaling.
8. What are the factors to be considered for transistor scaling?
9. Define constant voltage scaling.
10. What are the sources to be considered for design margin?


PART-B
1. Explain in detail about the following:
a) Resistance estimation (8)
b) Inductance estimation (8)
2. Explain about routing capacitance with neat diagram. (16)
3. With neat diagram explain about power dissipation. (16)
4. Briefly explain about the following:
a) CMOS transistor sizing (8)
b) Design margining (8)
5. Explain about scaling of MOS transistor dimensions and charge sharing. (16)
UNIT –IV
VLSI SYSTEM COMPONENTS CIRCUITS AND SYSTEM
LEVEL PHYSICAL DESIGN
PART-A
1. Write the difference between encoder and priority encoder.
2. Draw the CMOS implementation of 4-to-1 MUX using transmission gates.
3. Give the verilog coding for 4-bit magnitude comparator.
4. Draw the wheel floor plan
5. What is meant by clock distribution?
6. Design a circuit for finding the 9's compliment of a BCD number using 4-bit
binary adder and some external logic gates
7. What is physical verification?
8. Mention the levels at which testing of a chip can be done
9. What are the approaches in design for testability?
10. What is known as boundary scan register?
11. Design a set of CMOS gates to implement the sum function.
PART-B
1. Give the design procedure for 8 bit carry look ahead adder. (16)
2. Design a multiplier for the given sequence: (16)
EC1354 VLSI DESIGN
Kings College of Engineering, Punalkulam
a1 a2 a3 a4 a5 x b1 b2 b3
3. Draw the basic physical design for the inverter AND, OR and half-adder. (16)
4. Explain in detail about manufacturing of test principles. (16)
5. Explain the concept of clock distribution and power distribution. (16)
UNIT – V
VERILOG HARDWARE DESCRIPTION LANGUAGE
PART – A
1. What is Verilog?
2. What are identifiers?
3. What are gate primitives?
4. What is a FPGA?
5. Give the two blocks in behavioral modeling.
6. Define FSM.
7. Give the XILINX FPGA architecture
8. What is Switch-level modeling?
9 What is an antifuse?
10. What are the different types of modeling Verilog?
PART-B
1. Design a 4-bit carry look ahead adder and write the verilog HDL for it. (16)
2. Design 4X1 multiplexer and write the HDL for it in all four modeling: (16)
3. Briefly explain behavioral modeling(all functions) with an example: (16)
4. Design and develop a project in HDL to compare x5x4x3x2x1x0 with y5y4y3y2y1y0.
Check the output by means of test bench. (16)
5. Explain the following with an example:
i) Tasks and functions (4)
ii) Test bench for multiplexer (4)
iii) Difference between always and initial (4)
iv) Blocking and non-blocking statements (4)
6. Explain with a neat sketch the architecture of CLB’S available in xilinx XC 3000
series FPGA (16)
----------------------------

tqm

MG 1301 TOTAL QUALITY MANAGEMENT
KINGS COLLEGE OF ENGINEERING, PUNALKULAM 1
KINGS
COLLEGE OF ENGINEERING
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
ACADEMIC YEAR 2011- 2012 / ODD SEMESTER
QUESTION BANK
SUBJECT CODE/NAME: MG1301 TOTAL QUALITY MANAGEMENT
YEAR / SEM: III / V
UNIT- I
INTRODUCTION
PART – A (2 MARKS)
1. Define Total Quality?
2. Define Quality?
3. What are the Dimensions of Quality?
4. Give the Basic Concepts of TQM?
5. Give the Principles of TQM?
6. Give the Obstacles associated with TQM Implementation?
7. Give the Analysis Techniques for Quality Costs?
8. Define Quality Costs?
9. Give the primary categories of Quality cost?
10. Give the typical cost bases?
11. How will you determine the optimum cost?
12. State the Quality Improvement Strategy?
13. Define Quality Planning?
14. Give the Objectives of TQM?
15. What is needed for a leader to be effective?
16. What is the important role of senior management?
17. What are the general duties of a quality council?
18. What does a typical meeting agenda contain after establishing the TQM?
19. What are the various quality statements?
20. Give the basic steps to strategic quality planning?
21. What is a quality policy?
MG 1301 TOTAL QUALITY MANAGEMENT
KINGS COLLEGE OF ENGINEERING, PUNALKULAM 2
PART – B
1. What is quality cost? Explain the techniques used for Quality cost? (16)
2. Explain the principles of TQM? (16)
3. Explain Deming Philosophy? (16)
4. Explain the barriers to TQM implementation? (16)
5. Explain the concepts of Leadership? (16)
UNIT- II
TQM PRINCIPLES
PART – A (2 MARKS)
1. What is a mission statement?
2. What is a vision statement?
3. What are the important factors that influenced purchases?
4. Give the need for a feedback in an organization?
5. List the tools used for feedback?
6. What are the activities to be done using customer complaints?
7. What are the elements of customer service?
8. Define Customer Retention?
9. Define Employee Involvement?
10. State Maslow’s Hierarchy of Needs?
11. State Frederick Herzberg’s Two-factor theory?
12. What does an employee want?
13. What are the concepts to achieve a motivated work force?
14. Define Empowerment?
15. What are the three conditions necessary to create the empowered environment?
16. What are the types of teams?
17. What are the characteristics of successful teams?
18. What are the decision-making methods?
19. What are the stages of team development?
20. Give some common team problems?
21. What are the common barriers to team progress?
22. Give the steps involved in training process?
23. Define Recognition and Reward?
24. What are the types of appraisal formats?
25. What are the benefits of employee involvement?
MG 1301 TOTAL QUALITY MANAGEMENT
KINGS COLLEGE OF ENGINEERING, PUNALKULAM 3
26. What are the basic ways for a continuous process improvement?
27. What are the three components of the Juran Trilogy?
28. What are the steps in the PDSA cycle?
29. What are the phases of a Continuous Process Improvement Cycle?
30. Define 5S?
31. What is a Kaizen?
32. What are the three key elements to a partnering relationship?
33. What are the three types of sourcing?
34. What are the ten conditions for the selection and evaluation of suppliers?
35. What are the characteristics used to measure the performance of a particular process?
36. Give the six basic techniques for presenting performance measures?
37. Give the usage of an effective recognition and reward system?
38. How will you improve the performance appraisal system?
39. What are the typical measurements frequently asked by managers and teams?
PART – B
1. Explain Juran trilogy for Continuous Process Improvement? (16)
2. Explain the PDSA cycle? (16)
3. Explain Kaizen principle? (16)
4. Explain how the employee will be involved in doing a process? (16)
UNIT- III
STATISTICS PROCESS CONTROL
PART – A (2 MARKS)
1 Define Statistics?
2. What is a measure of central tendency?
3. What is Measures of dispersion?
4. What is a normal curve?
5. What is the use of the control chart?
6. Give the objectives of the attribute charts?
7. Define Six Sigma Problem Solving Method?
8. What are the new seven management tools?
9. Give the seven tools of quality?
10. Give the usage of C&E diagrams?
11. Define Six Sigma?
12. What are the various histogram shapes?
13. Differentiate Population & Sample?
14. Give the sources of variation?
MG 1301 TOTAL QUALITY MANAGEMENT
KINGS COLLEGE OF ENGINEERING, PUNALKULAM 4
15. Define Run chart?
16. Define Control chart?
17. What are the various patterns of scatter diagrams?
18. What is the procedure for constructing the tree diagram?
19. Give at least five standard formats of matrix diagram?
20. What are the benefits of an activity network diagram?
PART – B
1. Explain the QC or SPC tools? (16)
2. Explain the Seven Management Tools? (16)
3. Plot the control chart for variables and attributes (16)
4. Explain the concepts of Six Sigma? (16)
UNIT- IV
TQM TOOLS
PART – A (2 MARKS)
1. Define Benchmarking?
2. Enumerate the steps to benchmark?
3. What are the types of benchmarking?
4. What is a QFD?
5. What are the benefits of QFD?
6. What are the steps required to construct an affinity diagram?
7. What are the parts of house of quality?
8. How will you build a house of quality?
9 .Define FMEA?
10. What are the stages of FMEA?
11. What are the goals of TPM?
12. Give the seven basic steps to get an organization started toward TPM?
13. What are the major loss areas?
14. What are the generic steps for the development and execution of action plans in
benchmarking?
15. What are the phases of QFD process?
16. What are the several types of FMEA?
17. Define TPM?
MG 1301 TOTAL QUALITY MANAGEMENT
KINGS COLLEGE OF ENGINEERING, PUNALKULAM 5
PART – B
1. Explain the Bench marking Process and reasons to Benchmark? (16)
2. Explain the QFD process? (16)
3. Explain the House of Quality in Quality Function Deployment? (16)
4. What is FMEA? Explain the stages of FMEA? (16)
UNIT- V
QUALITY SYSTEMS
PART – A (2 MARKS)
1. Give the ISO 9000 Series of Standards?
2. What is the need for ISO 9000?
3. Give some other quality systems?
4. Give the objectives of the internal audit?
5. What are the requirements of ISO 14001?
6. What are the benefits of ISO 14000?
7. What are the four elements for the checking & corrective action of ISO 14001?
8. What are the seven elements for the implementation & operations of ISO 14001?
9. What are the four elements for the planning of ISO 14001?
10. Give the types of Organizational Evaluation Standards?
11. Give the types of Product Evaluation Standards?
12. Define Quality Audits?
13. Analyze TQM?
14. What are the benefits of ISO?
15. Give the ISO 9001 requirements?
16. What are the methods of actual audit?
PART – B
1. Explain the elements of ISO 9000:2000? (16)
2. Explain the implementation and documentation of Quality System? (16)
3. Explain the requirements of ISO 14000? (16)
4. Explain the Benefits of ISO 14000? (16)
5. Discuss about ISO 9000:2000 Quality Systems? (16)
MG 1301 TOTAL QUALITY MANAGEMENT
KINGS COLLEGE OF ENGINEERING, PUNALKULAM 6
6. Why is ISO 9000 important? Explain briefly. (16)

em2

EE1301- ELECTRICAL MACHINES - II
KINGS COLLEGE OF ENGINEERING, PUNALKULAM 1
KINGS
COLLEGE OF ENGINEERING
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
ACADEMIC YEAR 2011- 2012 / ODD SEMESTER
QUESTION BANK
SUBJECT CODE/NAME: EE1301-ELECTRICAL MACHINES – II
YEAR / SEM: III / V
UNIT – I
SYNCHRONOUS GENERATOR
PART –A (2 MARKS)
1. State the type of synchronous generator used in hydro electrical power station.
2. Name the main parts of synchronous generator.
3. Write down the EMF equation of Alternator.
4. Define regulation of Alternator.
5. Name the different methods of determining the voltage regulation of synchronous
generator.
6. What is the speed of a 4 pole 50Hz Synchronous machine?
7. State the other two names of AC generator?
8. Define Synchronous speed.
9. What are the components of synchronous impedance?
10. How can a DC generator be converted into an alternator?
PART –B
1. Find the no load phase and line voltages of a star connected 3 phase, 6 pole
alternator which runs at 1200 rpm, having flux per pole of 0.1wb sinusoidally
distributed. It’s stator has 54 slots having double layer winding. Each coil has 8 turns
and the coil is chorded by 1 slot. (16)
2. The open circuit and short circuit readings for a 3 phase, star connected 1000kVA,
2000V, 50Hz, synchronous generator are:
Field
amperes
10 20 25 30 40 50
OC
terminal
voltage(V)
800 1500 1760 2000 2350 2600
SC
armature
current(A)
- 200 250 300 - -
EE1301- ELECTRICAL MACHINES - II
KINGS COLLEGE OF ENGINEERING, PUNALKULAM 2
The armature effective temperature is 0.2Ω per phase. Draw the characteristics
curves and estimate the full-load percentage regulation at 0.8pf lagging and 0.8pf
leading. (16)
3. A 3300V, 3phase star connected alternator has a full load current of 100A. On
short circuit a field current of 5A was necessary to produce full load current. The emf
on open circuit for the same excitation was 900V. The armature resistance was 0.8
Ω/phase. Determine the full load voltage regulation for (1)0.8pf lagging (2)0.8pf
leading. (16)
4. A 3 phase, 50Hz star connected 2000kA for a certain field excitation. With the
same excitation, the open circuit voltage was 900V. The resistance between a pair of
terminals was 0.12 Ω. Find the full load regulation at UPF and 0.8pf lagging. Draw
the phasor diagrams. (16)
5. A 3 phase 16 pole alternator has a star connected winding with 144 slots and 10
conductors per slot. The flux per pole 0.04wb and is sinusoidally distributed. The
speed is 375 rpm. Find the frequency, phase emf and line emf. The coil span is 160ο
electrical. (16)
6. (a) Describe the principle and construction of slow speed operation generator with
neat diagram (8)
(b) Derive the emf equation of alternator. (8)
7. What are the methods of determining regulation of alternator? Discuss each briefly
(16)
8. Explain the procedure for POTIER method to calculate voltage regulation of
alternator (16)
9. For a salient pole synchronous machine, prove the d-axis synchronous reactance
Xd, can be obtained from its OCC and SCC. Neglect armature resistance. (16)
10. Explain the condition for parallel operation of 3 phase alternator with neat
diagram (16)
EE1301- ELECTRICAL MACHINES - II
KINGS COLLEGE OF ENGINEERING, PUNALKULAM 3
UNIT- II
SYNCHRONOUS MOTOR
PART –A (2 MARKS)
1. What are the main parts of synchronous motor?
2. Explain why synchronous motor has no starting torque.
3. What is synchronous capacitor?
4. Synchronous motor always runs at synchronous speed why?
5. What is hunting?
6. What are V-Curves?
7. What are the uses of damper windings in a synchronous motor?
8. How do you operate the synchronous motor at any desired pf?
9. What will be the pf when the synchronous motor is operated at under excited conditions?
10. What are the different methods of starting synchronous motor?
PART-B
1. (a) Explain the methods of starting synchronous motor against high-torque loads.
(8)
(b) Explain various torques associated with synchronous motor. (8)
2. (a) Draw the equivalent circuit and phasor diagram of a synchronous motor. (8)
(b) Explain the significance of V and inverted V curves. (8)
3. (a). Explain the working of synchronous motor with different excitations (8)
(b) List out the main characteristic features of synchronous motor. (8)
4. Discuss the following
(i) Constant excitation circle (8)
(ii) Constant power circle (8)
5. Derive the mechanical power developed per phase of a synchronous motor (16)
6. A 3300V,3 phase synchronous motor running at 1500 rpm has its excitation kept
constant corresponding to no-load terminal voltage of 3000V. Determine the power
input, power factor and torque developed for an armature current of 250A if the
synchronous reactance is 5 Ω per phase and armature resistance is neglected. (16)
7. A synchronous motor having 40% reactance and negligible resistance is to be
operated at rated voltage at UPF,0.8pf lag,0.6pf lag, 0.8pf lead and 0.6pf lead. What
are the values of induced emf. (16)
8. A 75 kW,400V, 4 pole, 3 phase, star connected synchronous motor has a
resistance and synchronous reactance per phase of 0.04Ω and 0.4 Ω respectively.
EE1301- ELECTRICAL MACHINES - II
KINGS COLLEGE OF ENGINEERING, PUNALKULAM 4
Compute for full load 0.8pf lead the open circuit emf per phase and gross mechanical
power developed. Assume an efficiency of 92.5%. (16)
9. A 6600V,3 phase, star connected synchronous motor draws a full load current of
80A at 0.8pf leading. The armature resistance is 2.2 Ω and reactance of 22 Ω per
phase. If the stray losses of the machine are 3200w. Find (i) Emf induced
(ii)Output power (iii) Efficiency of the machine. (16)
10. A 2000V,3 phase, 4 pole, star connected synchronous motor runs at 1500rpm.
The excitation is constant and corresponding to an open circuit voltage of 2000V.
The resistance is negligible in comparison with synchronous reactance of 3.5 Ω/ph.
For an armature current of 200A.Determine (i) power factor (ii) power input (iii) torque
developed. (16)
UNIT - III
THREE PHASE INDUCTION MOTOR
PART- A (2 MARKS)
1. Name the two type of rotor of an induction motor?
2. What is the principle of operation of induction motor?
3. How will you change the direction of rotation of three phase induction motor?
4. What is Slip?
5. List the application of slip ring induction motor?
6. Why an induction motor is called asynchronous motor?
7. State the effect of rotor resistance on starting torque?
8. What is the crawling of an induction motor?
9. What is cogging?
10. How the power factor of an induction motor varies when its load increases?
PART B
1. Explain the construction and working of three phase induction motor. (16)
2. Explain the power flow diagram and torque slip characteristics of induction motor.
(16)
3. Derive the torque equation of a three phase induction motor (16)
4. Develope an equivalent circuit for three phase induction motor. State the
difference between exact and approximate equivalent circuit. (16)
5. The power input to the rotor of a 3 phase, 50 HZ, 6 pole induction motor is 80 KW
.The rotor emf makes 100 complete alternations per minute. Find
i. Slip
ii. Motor Speed
iii. Mechanical power developed
iv. Rotor copper loss per phase
EE1301- ELECTRICAL MACHINES - II
KINGS COLLEGE OF ENGINEERING, PUNALKULAM 5
v. Rotor resistance per phase if rotor current is 65 A
vi. Torque developed (16)
6. Derive the equation for torque developed by an induction motor .Draw a typical
torque – slip curve and deduce the condition for maximum torque. (16)
7. (a) A 3300V,10 pole ,50HZ three phase star connected induction motor has slip
ring rotor resistance per phase =0.015 ohm and standstill reactance per phase =0.25
ohm .If the motor runs at 2.5 percent slip on full load ,find.
i. Speed of the motor
ii. Speed at which the torque will be maximum
iii. The ratio of maximum torque to full load torque. (10)
(b) A 3 phase, 4 pole, 50 HZ induction motor is running at 1440 rpm. Determine the
slip speed and slip. (6)
8. A 3ph, 400 V IM, gave the test readings:
No load test: 400 V, 1250W, 9A
SC test: 150V, 4KW, 38A
Draw the circle diagram If the normal rating is 14.91 KW, find from the circle diagram,
the full load current and slip. (16)
UNIT- IV
STARTING AND SPEED CONTROL OF THREE PHASE INDUCTION
MOTOR
PART-A (2 MARKS)
1. What is the function of starter?
2. List the disadvantages of autotransformer starter.
3. What are the advantages of DOL starter?
4. Name the different methods of electric braking.
5. What are the advantages of dynamic braking of an induction motor?
6. What is the disadvantage of dynamic braking of an induction motor?
7. What is eddy current loss?
8. How does the slip vary with load?
9. Is it possible to start 3 phase slip ring induction motor on load?
10. What do you mean by negative slip?
PART B
1. With neat diagrams explains the working of any two types of starters used for
squirrel cage type 3 phase induction motor. (16)
2. Discuss the various starting methods of induction motors. (16)
EE1301- ELECTRICAL MACHINES - II
KINGS COLLEGE OF ENGINEERING, PUNALKULAM 6
3. Explain the different speed control methods of phase wound induction motor (16)
4. Explain the various schemes of starting squirrel cage induction motor. (16)
5. Explain the speed control of 3 phase squirrel cage induction motor by pole
changing. (16)
6. Discuss the theory of star – delta starter. (16)
7. Explain briefly the various speed control schemes of induction motors. (16)
8. Explain in detail the slip power recovery scheme. (16)
9. Explain the various techniques of sped control of induction motor from rotor side
control. (16)
10. Explain the cascade operation of induction motors to obtain variable speed. (16)
UNIT - V
SINGLE PHASE INDUCTION MOTORS AND SPECIAL MACHINES
PART- A (2 MARKS)
1. Name the application of AC series motor.
2. What is stepper motor?
3. What is the function of capacitor in a single phase induction motor?
4. What kind of motor is used in a mixie?
5. In which direction does a shaded pole induction motor run?
6. Why singe phase induction motor has low power factor?
7. What do you mean by split phase motor?
8. How will you change the direction of rotation of a repulsion motor?
9. What happens when the centrifugal switch fails to close?
10. Name the different classification of stepper motor?
PART - B
1. Give the classification of single phase motors .Explain any two types of single
phase induction motors. (16)
2. Explain the double field revolving theory for operation of single phase induction
motor. (16)
3. Explain the operation of shaded pole induction motor with diagram. (16)
EE1301- ELECTRICAL MACHINES - II
KINGS COLLEGE OF ENGINEERING, PUNALKULAM 7
4. Develop equivalent circuit of a single phase induction motor ignoring core losses.
(16)
5. Explain the working principle of single phase induction motor .Mention its four
applications. (16)
6. What is the principle and working of hysteresis motor? Explain briefly. (16)
7. Explain the construction and working of stepper motor. (16)
8. Explain the principle of operation and applications of reluctance motor. (16)
9. Explain the principle of operation and applications of repulsion motor and
hysteresis motor. (16)