QUESTION BANK
PART A
- State ohm’s law.
- State kirchoff’s law.
- Which law is applicable for branch current method?
- What is the matrix formation equation for mesh and
nodal method?
- Compare series and parallel circuits.
- A 5W and 15W
resistors are connected in series to the 50 V battery and 20 W
and 15 W
resistors are connected in parallel to the same battery. Determine the
total resistance value?
- Draw the phasor diagram for RL and RC circuits
- What is meant by network?
- What is called branch?
- What is called node?
- Define power factor?
- Mention the application of electrical circuits?
- List the methods for writing the circuit equation?
- What is the drawback in mesh method?
- What is the application of series circuits?
- Differentiate mesh and nodal analysis.
- What is meant by active element?
- Is the silicon diode, is uni-lateral element? Why?
- Give examples of passive elements?
- Differentiate active and passive elements?
- Two resistors are connected in parallel and a voltage
of 200volts is applied to the terminals. The total current taken is 25A
and the power dissipated in one of the resistors is 1500Watts. What is the
resistance of each element?
- Calculate
the equivalent resistance of the following combination of resistor and
source current.
- Compare AC and DC circuit
- Let Z=
(8+j6) Ω, convert this into polar form.
- Define
active and reactive power in AC circuits.
Part-B
1. Write the mesh
equations for the circuit shown in the figure and determine the current in 12W
resistor.
(12)
2. Apply mesh current method and determine currents through
the resistors of the network shown in figure.
(12)
3) Find the voltages V in the
circuit shown in figure which makes the current in the 10 W
resistor to be zero by using nodal analysis
4) A Wheat stone bridge circuit is
made up of the following resistors AB=3W BC=6W and
CD=15 W
and DA=7 W
.A 30 V battery is connected between
A&C.find the current through a 10W galvanometer connected
between B&D using loop method. (12)
5)
(i) Compare series and parallel
method (6)
. (ii) Derive the equation of nodal voltage
method by using 3 nodes and form the matrix. (6)
6. (i) Find the Equivalent resistance and the current in
each resistance.
(6)
(ii) Derive the
equation of 2 loop circuit and form the matrix using mesh current
method. (6)
7. Explain the following
(i)
active elements (ii)
passive elements
(iii)
bilateral&uni lateral (iv)open circuit
(v)short
circuit (vi)network (6X 2)
8.Derive the matrix equation for
3 loop circuit?
9. Write the mesh equation for the network shown in
figure by inspection and find the power absorbed by 8Ω resistor. (12)
10.Find the currents I1 ,
I2, I3 and the voltages Va and Vb
in the network of figure by using nodal analysis. (12)
UNIT II
PART-A
- State Super Position Theorem
- State Thevenins Theorem
- State Norton’s
Theorem
- State Maximum power transfer theorem
- State Millman’s Theorem
- State Reciprocity Theorem
- For the network shown in the following fig, convert
the voltage source into current source
- Draw the equivalent circuit for Norton’s theorem
- Compare Thevenin’s theorem and Norton’s theorem
- How to change the (a) current source into voltage
source (b) voltage source into current source?
- Give one example problem of voltage to current source
transformation?
- Which theorem is used to find the maximum power for a
linear/nonlinear network?
- With example explain the transformation of three
voltage source is in series with three resistance combination?
- Write the formula for star to delta transformation.
- Write the formula for delta to star transformation.
- Draw the phase angle diagram of R, Y, B in star
connection?
- Write the formula for finding the Thevenin’s
resistance
- What is the formula for load current in Norton’s
Theorem?
- Draw the equivalent circuit of Norton’s Theorem
- What is the current formula for Maximum power
transfer theorem?
- Draw the equivalent circuit for Thevenin’s theorem
- What are the steps followed in Compensation Theorem?
- When the maximum power transfer will occur?
- Which theorem is valid for linear circuit?
- Which theorem is applicable for linear / bilateral
networks?
PART-B
- (a) Find the Voltage Across the 2Ω resistor by using
super position theorem
(8)
(b)
Write the steps involved in the superposition theorems (4)
- Two generators with emfs 200 V and 250 V and armature resistance of 2 Ω
and
1Ω respectively are in
parallel supplying a load resistance of 10 Ω.find (a) current
Supplied by each generator
(b) load current and (c) load voltage. Use super
Position theorem (12)
- (a) For the circuit shown below find the Thevenin’s
equivalent circuit ,preserving terminals A and B .Calculate the current
through a 2 Ω resistor connected
across the terminals AB (8)
(b) Write the steps involved in the Thevenin’s theorem (4)
- (a) Explain reciprocity theorem (6)
(b)
Write the steps involved in the Norton’s theorem (6)
- (a) Write short notes on Maximum power transfer
theorem (4)
(b)
Find the voltage between points A&B in the fig below using Norton’s theorem
(8)
- (a) For the circuit of the fig find the value RL
for maximum power delivered to it.
Calculate also the maximum load power. (8)
(b) State the condition of Millman’s theorem for
voltage source (4)
- Use
superposition theorems to find the voltage across the terminals A and B
and also the current through RL
= 5 Ω (12)
- Write short notes on (i)Star to Delta conversion (6)
(ii)Delta to Star conversion (6)
and also derive the conditions
9. (i) Write short notes on substitution theorem (4)
(ii)
In the network shown in the fig (a) the 5 Ω resistor is changed to 8 Ω
determine the change in the current through (3+j4) Ω impedance using Thevenin’s
theorem. (8)
10. For the circuit shown in figure, determine the
load current by applying Thevenin’s
theorem.
(12)
Unit-3
PART-A
- Write the condition of resonance.
- Define band width.
- Draw the series resonance circuit and the phasor
diagram.
- Draw the parallel resonance circuit and the phasor
diagram.
- Compare series and parallel resonance circuits.
- Two inductively coupled coils have self inductance L1=45
mH and L2=150 mH. If the co-efficient of coupling is 0.5, (i)
find the value of mutual inductance between the coils and (ii) what is the
maximum possible mutual inductance?
- Define mutual inductance.
- Determine the value of capacitive reactance and
impedance at resonance. When
R = 10ohm, C =25µF and L
=10mH
- Define of quality factor.
- Define coefficient of coupling?
- Write about coupled circuits.
- For which condition, the net reactance is capacitive?
- Write the equation for maximum power absorption
- When the series A.C circuit is at resonance?
- Mention the relationship between Q-factor and
bandwidth
- A coil of resistance 2ohm and inductance 0.01H is
connected in series with capacitor C. If maximum current occurs at 25Hz
find C?
- What is resonance frequency and Bandwidth of a series
RLC circuit in which R=5ohm, L=40mH, C=1µF?
- Define Series Resonance
- What is meant by parallel resonance?
- Draw the reactance curves for inductive load
- In rectangular form,
what is the value of impedance and admittance
- Draw the frequency response of R-L circuit and
explain
- In a parallel RL circuit R=3ohm and XL =4ohm.What is the value
of admittance?
- What do you understand by damped frequency?
- What is the maximum possible mutual inductance of two
inductively coupled coils with self inductance L1=25mH and L2=100mH?
PART –B
1. (i) Derive
the resonant frequency of series circuit. (6)
(ii) Short notes on Q- factor and its
effect on band width. (6)
2. (i) Compare
series and parallel resonance circuits (6)
(ii) Give the short notes on (a)
co-efficient of coupling and (b) dot convention (6)
3. (i) Derive
the band width of RLC circuit. (6)
(ii) A coil having a resistance of 50 Ω and
an inductor of 0.2 H is connected in series with a variable capacitor across a
60 V, 50 Hz supply .Calculate the capacitance required to produce resonance and
the corresponding values of (a)current (b)voltage across the coil and the
capacitor (c)the power factor (d)Q-factor. (6)
4. (i) Derive
the Q-factor of parallel resonance circuit. (4)
(ii) One RLC circuit has R= 30 Ω, L=40 mH
and C= 50 µ₣. Find the resonant frequency .Under resonant conditions, Calculate
the current and voltage drops across the R, L, and C if applied voltage is 120
V. (8)
5. (i) A 50 Ω
resistor is connected in series with an inductor having internal resistance
,a
Capacitor and 100 V variable frequency
supply as shown in fig. At a frequency of
200Hz, the maximum current of 0.7A flows
through the circuit and voltage across the C is 200 V .Determine the circuit
constants (8)
(ii) Derive the resonant frequency of parallel
circuit. (4)
6. (i) A series
RLC circuit consists of 50 Ω resistance ,0.2 H inductance and 10 µ₣ capacitor
with the applied voltage of 20 V .Determine the resonant frequency, Q-factor of
the circuit and compute the lower and upper frequency limits and also find the
band width of the circuit. (8)
(ii) Write a short notes on multi winding
coupled circuit. (4)
7. (i) Give the
short notes on coupled circuit and inductively coupled circuit. (6)
(ii) Explain Q-factor and band width.. (6)
8. A series circuit consisting of a 12W resistor, 84.4mF capacitor and a variable inductor is connected to a 100V,
50 cycle source. a)For the condition of resonance, determine the inductance
current and voltage drop across the inductor, b) determine the inductance
current and the voltage drop across the inductor when this voltage drop is a
maximum,
(12)
9. A series RLC circuit with R=10W, L =10 mH & C=1µF has
an applied voltage of 200 V at resonant frequency. Calculate the resonant
frequency, the current in the circuit and the voltages a cross the elements at
resonance. Find also the quality factor and bandwidth.
(12)
10. A current source is applied to a parallel combination of R,
L & C, where R =10W,
L =1H, &
C=1m F.
A)
Compute the resonant
frequency.
B)
Find the quality
factor.
C)
Calculate the value of
the bandwidth.
Compute the lower and upper half frequency points of the
band width . (12)
Unit-4
Part-A:
- What is the difference between balanced and
unbalanced circuits?
- In the measurement of three phase power using two
wattmeter method, when both the wattmeter read same values, what is the
value of power factor of the load?
- Explain how to solve unbalanced neutral isolated
three phase load connected to a balanced supply?
- Give the relation connecting the power factor angle
with the two wattmeter readings.
- What is floating neutral?
- Write the types of unbalanced load?
- Write about symmetrical component method?
- What is meant by positive sequence component?
- What is meant by negative sequence component?
- What is zero sequence component?
- The two line currents taken by an unbalanced delta
connected load are
Ia=10
-120 A, Ib=5 150 A. What is the line current Ic?
- What is meant by phase sequence?
- Define positive phase sequence
- What are the identification colours of RYB?
- What are the main objectives of interconnection of
the phases?
- What are the types of interconnections?
- Write the relation between phase voltage and line
voltage in star connected system.
- Write the relation between phase voltage and line
voltage in delta connected system.
- Write the
condition for balanced star connected load
- Draw the
circuit diagram for balanced delta
connected load
- A balanced star connected load of (3-j4ohm)
impendance is connected to 400 V three phase supply. What is the real
power consumed?
- A symmetrical three phase, 400 V system supplies a
balanced mesh connected load. The current in each branch circuit is 20A
and the phase angle is 40 degree lag. Fine (a) the line current (b) the
total power
- What are the four
methods can be analyzed in unbalanced star connected load
- Define three phase balance load
- Explain balance supply system
Part-B
1. Explain three
phase power measurement by 2 wattmeter method for star and delta connected load
and determine the power equation and draw the phasor diagram.
(12)
2. (i) Explain
three phase power measurement by 3ammeter and 3 volt meter method
(6)
(ii) Give the short notes on balanced
star-delta and delta-star conversion. (6)
3. (i) Derive
the expression for balanced star connected load and draw the phaser diagram. (6)
(ii) Give the short notes on symmetrical
components and un-symmetrical components.
(6)
4. (i) Explain
three phase power measurement by 2 wattmeter method and determine the power
factor equation (6)
(ii)
Two wattmeter method is used to measure power in a 3 phase load, the wattmeter
readings are 400 W and -35 W .Calculate (i) total active power (ii) power
factor and (iii) reactive power (6)
5. (i) Derive
the expression for balanced delta connected load and draw the phasor diagram. (6)
(ii)A balanced star connected load of (3-j4)
Ω impedance is connected to 400 v three phase supply. What is the real power
consumed? (6)
6. (a) Derive
the expression for un balanced star connected load and draw the phaser
Diagram. (6)
(b) A balanced star connected load of (8+j6)
Ω /phase is connected to a 3 phase, 230 V, 50c/s supply. Find the line current,
power factor and power
(6)
7. (a) Derive
the expression for un - balanced delta connected load and draw the phaser
diagram.
(6)
(b) Derive the expression for total power
in a 3 phase balanced circuit. (6)
8. (i)A balanced
delta connected load takes a line current of 15 A when connected to a
balanced 3 phase 400 v system. A
wattmeter with its current coil in one line and
Potential coil between the two remaining
lines read 2000W. Describes the load
Impedance. . (6)
(ii) In a balanced 3 phase system, the power
is measured by 2 wattmeter method and the
Ratio of two wattmeter method is
2:1.Determine the power and power factor. .
(6)
9. (a) Derive the expression for 3 wire star connected unbalanced load. . (6)
(b) Derive the expression for 4 wire
star connected unbalanced load. (6)
Unit-5
Part-A
- Define transient response.
- Define forced response.
- Compare steady state and transient state
- Define transient state and transient time
- Draw the DC response of R-L circuit and the response
curve.
- Draw the DC response of R-C circuit and the response
curve
- Draw the DC response of R-L –C circuit and the
response curve
- Draw the sinusoidal response of R-L circuit and write
the differential equation.
- Draw the sinusoidal response of R-C circuit and write
the differential equation.
- Draw the sinusoidal response of R-L -C circuit and
write the differential equation.
- Define Laplace
transform.
- Write 2 properties of Laplace
transformations.
- Give an example for forced response
- Define source – free response
- Define Zero- Input response
- Define Zero – State response
- Write the boundary conditions for the inductance
- Write the boundary conditions for the capacitance
- What are the effects of switching on resistor
- Write the steps to be involved in the determination
of initial conditions
- Define damping ratio?
- Sketch the current given by i(t)= 5 – 4 e-20t
- What are the three cases involved in R-L-C transients
- Distinguish between free response and forced response
- Define a time constant?
Part-B
1. (i)Draw the
DC response of R-L circuit and derive the power equation of resistor and
inductor. . (6)
(ii)Draw the DC response of R-C circuit and
derive the power equation of resistor and capacitor. . (6)
2. Draw the DC
response of R-L-C circuit and derive the equation of over damped, under damped
and critically damped. (12)
3. The circuit
shown in figure consists of resistance, inductance and capacitance in
Series with a 100 V constant source. When
the switch is closed at t = 0, find the
Current transient. (12)
4. Draw the
sinusoidal response of R-L circuit and determine the current equation.(12)
5. Draw the
sinusoidal response of R-C circuit and determine the current equation(12)
6. Draw the
sinusoidal response of R-L-C circuit and determine the current equation
(12)
7. The circuit
consisting of a series RLC elements with R=10 Ω, L=0.5 H and C=200 µ₣ has a
sinusoidal voltage V=150 sin (200t+ Ф).If the switch is closed when Ф =30•
.Determine the current equation. (12)
8.(i) The
circuit consists of series RL elements with R= 150 Ω and L=0.5H. The switch is
closed when Ф=30•.Determine the resultant current when voltage=150
cos (100t+ Ф) V.
(6)
(ii) Write short notes on transient analysis. (6)
EE2151 CIRCUIT THEORY
QUESTION BANK
PART A
- State ohm’s law.
- State kirchoff’s law.
- Which law is applicable for branch current method?
- What is the matrix formation equation for mesh and
nodal method?
- Compare series and parallel circuits.
- A 5W and 15W
resistors are connected in series to the 50 V battery and 20 W
and 15 W
resistors are connected in parallel to the same battery. Determine the
total resistance value?
- Draw the phasor diagram for RL and RC circuits
- What is meant by network?
- What is called branch?
- What is called node?
- Define power factor?
- Mention the application of electrical circuits?
- List the methods for writing the circuit equation?
- What is the drawback in mesh method?
- What is the application of series circuits?
- Differentiate mesh and nodal analysis.
- What is meant by active element?
- Is the silicon diode, is uni-lateral element? Why?
- Give examples of passive elements?
- Differentiate active and passive elements?
- Two resistors are connected in parallel and a voltage
of 200volts is applied to the terminals. The total current taken is 25A
and the power dissipated in one of the resistors is 1500Watts. What is the
resistance of each element?
- Calculate
the equivalent resistance of the following combination of resistor and
source current.
- Compare AC and DC circuit
- Let Z=
(8+j6) Ω, convert this into polar form.
- Define
active and reactive power in AC circuits.
Part-B
1. Write the mesh
equations for the circuit shown in the figure and determine the current in 12W
resistor.
(12)
2. Apply mesh current method and determine currents through
the resistors of the network shown in figure.
(12)
3) Find the voltages V in the
circuit shown in figure which makes the current in the 10 W
resistor to be zero by using nodal analysis
4) A Wheat stone bridge circuit is
made up of the following resistors AB=3W BC=6W and
CD=15 W
and DA=7 W
.A 30 V battery is connected between
A&C.find the current through a 10W galvanometer connected
between B&D using loop method. (12)
5)
(i) Compare series and parallel
method (6)
. (ii) Derive the equation of nodal voltage
method by using 3 nodes and form the matrix. (6)
6. (i) Find the Equivalent resistance and the current in
each resistance.
(6)
(ii) Derive the
equation of 2 loop circuit and form the matrix using mesh current
method. (6)
7. Explain the following
(i)
active elements (ii)
passive elements
(iii)
bilateral&uni lateral (iv)open circuit
(v)short
circuit (vi)network (6X 2)
8.Derive the matrix equation for
3 loop circuit?
9. Write the mesh equation for the network shown in
figure by inspection and find the power absorbed by 8Ω resistor. (12)
10.Find the currents I1 ,
I2, I3 and the voltages Va and Vb
in the network of figure by using nodal analysis. (12)
UNIT II
PART-A
- State Super Position Theorem
- State Thevenins Theorem
- State Norton’s
Theorem
- State Maximum power transfer theorem
- State Millman’s Theorem
- State Reciprocity Theorem
- For the network shown in the following fig, convert
the voltage source into current source
- Draw the equivalent circuit for Norton’s theorem
- Compare Thevenin’s theorem and Norton’s theorem
- How to change the (a) current source into voltage
source (b) voltage source into current source?
- Give one example problem of voltage to current source
transformation?
- Which theorem is used to find the maximum power for a
linear/nonlinear network?
- With example explain the transformation of three
voltage source is in series with three resistance combination?
- Write the formula for star to delta transformation.
- Write the formula for delta to star transformation.
- Draw the phase angle diagram of R, Y, B in star
connection?
- Write the formula for finding the Thevenin’s
resistance
- What is the formula for load current in Norton’s
Theorem?
- Draw the equivalent circuit of Norton’s Theorem
- What is the current formula for Maximum power
transfer theorem?
- Draw the equivalent circuit for Thevenin’s theorem
- What are the steps followed in Compensation Theorem?
- When the maximum power transfer will occur?
- Which theorem is valid for linear circuit?
- Which theorem is applicable for linear / bilateral
networks?
PART-B
- (a) Find the Voltage Across the 2Ω resistor by using
super position theorem
(8)
(b)
Write the steps involved in the superposition theorems (4)
- Two generators with emfs 200 V and 250 V and armature resistance of 2 Ω
and
1Ω respectively are in
parallel supplying a load resistance of 10 Ω.find (a) current
Supplied by each generator
(b) load current and (c) load voltage. Use super
Position theorem (12)
- (a) For the circuit shown below find the Thevenin’s
equivalent circuit ,preserving terminals A and B .Calculate the current
through a 2 Ω resistor connected
across the terminals AB (8)
(b) Write the steps involved in the Thevenin’s theorem (4)
- (a) Explain reciprocity theorem (6)
(b)
Write the steps involved in the Norton’s theorem (6)
- (a) Write short notes on Maximum power transfer
theorem (4)
(b)
Find the voltage between points A&B in the fig below using Norton’s theorem
(8)
- (a) For the circuit of the fig find the value RL
for maximum power delivered to it.
Calculate also the maximum load power. (8)
(b) State the condition of Millman’s theorem for
voltage source (4)
- Use
superposition theorems to find the voltage across the terminals A and B
and also the current through RL
= 5 Ω (12)
- Write short notes on (i)Star to Delta conversion (6)
(ii)Delta to Star conversion (6)
and also derive the conditions
9. (i) Write short notes on substitution theorem (4)
(ii)
In the network shown in the fig (a) the 5 Ω resistor is changed to 8 Ω
determine the change in the current through (3+j4) Ω impedance using Thevenin’s
theorem. (8)
10. For the circuit shown in figure, determine the
load current by applying Thevenin’s
theorem.
(12)
Unit-3
PART-A
- Write the condition of resonance.
- Define band width.
- Draw the series resonance circuit and the phasor
diagram.
- Draw the parallel resonance circuit and the phasor
diagram.
- Compare series and parallel resonance circuits.
- Two inductively coupled coils have self inductance L1=45
mH and L2=150 mH. If the co-efficient of coupling is 0.5, (i)
find the value of mutual inductance between the coils and (ii) what is the
maximum possible mutual inductance?
- Define mutual inductance.
- Determine the value of capacitive reactance and
impedance at resonance. When
R = 10ohm, C =25µF and L
=10mH
- Define of quality factor.
- Define coefficient of coupling?
- Write about coupled circuits.
- For which condition, the net reactance is capacitive?
- Write the equation for maximum power absorption
- When the series A.C circuit is at resonance?
- Mention the relationship between Q-factor and
bandwidth
- A coil of resistance 2ohm and inductance 0.01H is
connected in series with capacitor C. If maximum current occurs at 25Hz
find C?
- What is resonance frequency and Bandwidth of a series
RLC circuit in which R=5ohm, L=40mH, C=1µF?
- Define Series Resonance
- What is meant by parallel resonance?
- Draw the reactance curves for inductive load
- In rectangular form,
what is the value of impedance and admittance
- Draw the frequency response of R-L circuit and
explain
- In a parallel RL circuit R=3ohm and XL =4ohm.What is the value
of admittance?
- What do you understand by damped frequency?
- What is the maximum possible mutual inductance of two
inductively coupled coils with self inductance L1=25mH and L2=100mH?
PART –B
1. (i) Derive
the resonant frequency of series circuit. (6)
(ii) Short notes on Q- factor and its
effect on band width. (6)
2. (i) Compare
series and parallel resonance circuits (6)
(ii) Give the short notes on (a)
co-efficient of coupling and (b) dot convention (6)
3. (i) Derive
the band width of RLC circuit. (6)
(ii) A coil having a resistance of 50 Ω and
an inductor of 0.2 H is connected in series with a variable capacitor across a
60 V, 50 Hz supply .Calculate the capacitance required to produce resonance and
the corresponding values of (a)current (b)voltage across the coil and the
capacitor (c)the power factor (d)Q-factor. (6)
4. (i) Derive
the Q-factor of parallel resonance circuit. (4)
(ii) One RLC circuit has R= 30 Ω, L=40 mH
and C= 50 µ₣. Find the resonant frequency .Under resonant conditions, Calculate
the current and voltage drops across the R, L, and C if applied voltage is 120
V. (8)
5. (i) A 50 Ω
resistor is connected in series with an inductor having internal resistance
,a
Capacitor and 100 V variable frequency
supply as shown in fig. At a frequency of
200Hz, the maximum current of 0.7A flows
through the circuit and voltage across the C is 200 V .Determine the circuit
constants (8)
(ii) Derive the resonant frequency of parallel
circuit. (4)
6. (i) A series
RLC circuit consists of 50 Ω resistance ,0.2 H inductance and 10 µ₣ capacitor
with the applied voltage of 20 V .Determine the resonant frequency, Q-factor of
the circuit and compute the lower and upper frequency limits and also find the
band width of the circuit. (8)
(ii) Write a short notes on multi winding
coupled circuit. (4)
7. (i) Give the
short notes on coupled circuit and inductively coupled circuit. (6)
(ii) Explain Q-factor and band width.. (6)
8. A series circuit consisting of a 12W resistor, 84.4mF capacitor and a variable inductor is connected to a 100V,
50 cycle source. a)For the condition of resonance, determine the inductance
current and voltage drop across the inductor, b) determine the inductance
current and the voltage drop across the inductor when this voltage drop is a
maximum,
(12)
9. A series RLC circuit with R=10W, L =10 mH & C=1µF has
an applied voltage of 200 V at resonant frequency. Calculate the resonant
frequency, the current in the circuit and the voltages a cross the elements at
resonance. Find also the quality factor and bandwidth.
(12)
10. A current source is applied to a parallel combination of R,
L & C, where R =10W,
L =1H, &
C=1m F.
A)
Compute the resonant
frequency.
B)
Find the quality
factor.
C)
Calculate the value of
the bandwidth.
Compute the lower and upper half frequency points of the
band width . (12)
Unit-4
Part-A:
- What is the difference between balanced and
unbalanced circuits?
- In the measurement of three phase power using two
wattmeter method, when both the wattmeter read same values, what is the
value of power factor of the load?
- Explain how to solve unbalanced neutral isolated
three phase load connected to a balanced supply?
- Give the relation connecting the power factor angle
with the two wattmeter readings.
- What is floating neutral?
- Write the types of unbalanced load?
- Write about symmetrical component method?
- What is meant by positive sequence component?
- What is meant by negative sequence component?
- What is zero sequence component?
- The two line currents taken by an unbalanced delta
connected load are
Ia=10
-120 A, Ib=5 150 A. What is the line current Ic?
- What is meant by phase sequence?
- Define positive phase sequence
- What are the identification colours of RYB?
- What are the main objectives of interconnection of
the phases?
- What are the types of interconnections?
- Write the relation between phase voltage and line
voltage in star connected system.
- Write the relation between phase voltage and line
voltage in delta connected system.
- Write the
condition for balanced star connected load
- Draw the
circuit diagram for balanced delta
connected load
- A balanced star connected load of (3-j4ohm)
impendance is connected to 400 V three phase supply. What is the real
power consumed?
- A symmetrical three phase, 400 V system supplies a
balanced mesh connected load. The current in each branch circuit is 20A
and the phase angle is 40 degree lag. Fine (a) the line current (b) the
total power
- What are the four
methods can be analyzed in unbalanced star connected load
- Define three phase balance load
- Explain balance supply system
Part-B
1. Explain three
phase power measurement by 2 wattmeter method for star and delta connected load
and determine the power equation and draw the phasor diagram.
(12)
2. (i) Explain
three phase power measurement by 3ammeter and 3 volt meter method
(6)
(ii) Give the short notes on balanced
star-delta and delta-star conversion. (6)
3. (i) Derive
the expression for balanced star connected load and draw the phaser diagram. (6)
(ii) Give the short notes on symmetrical
components and un-symmetrical components.
(6)
4. (i) Explain
three phase power measurement by 2 wattmeter method and determine the power
factor equation (6)
(ii)
Two wattmeter method is used to measure power in a 3 phase load, the wattmeter
readings are 400 W and -35 W .Calculate (i) total active power (ii) power
factor and (iii) reactive power (6)
5. (i) Derive
the expression for balanced delta connected load and draw the phasor diagram. (6)
(ii)A balanced star connected load of (3-j4)
Ω impedance is connected to 400 v three phase supply. What is the real power
consumed? (6)
6. (a) Derive
the expression for un balanced star connected load and draw the phaser
Diagram. (6)
(b) A balanced star connected load of (8+j6)
Ω /phase is connected to a 3 phase, 230 V, 50c/s supply. Find the line current,
power factor and power
(6)
7. (a) Derive
the expression for un - balanced delta connected load and draw the phaser
diagram.
(6)
(b) Derive the expression for total power
in a 3 phase balanced circuit. (6)
8. (i)A balanced
delta connected load takes a line current of 15 A when connected to a
balanced 3 phase 400 v system. A
wattmeter with its current coil in one line and
Potential coil between the two remaining
lines read 2000W. Describes the load
Impedance. . (6)
(ii) In a balanced 3 phase system, the power
is measured by 2 wattmeter method and the
Ratio of two wattmeter method is
2:1.Determine the power and power factor. .
(6)
9. (a) Derive the expression for 3 wire star connected unbalanced load. . (6)
(b) Derive the expression for 4 wire
star connected unbalanced load. (6)
Unit-5
Part-A
- Define transient response.
- Define forced response.
- Compare steady state and transient state
- Define transient state and transient time
- Draw the DC response of R-L circuit and the response
curve.
- Draw the DC response of R-C circuit and the response
curve
- Draw the DC response of R-L –C circuit and the
response curve
- Draw the sinusoidal response of R-L circuit and write
the differential equation.
- Draw the sinusoidal response of R-C circuit and write
the differential equation.
- Draw the sinusoidal response of R-L -C circuit and
write the differential equation.
- Define Laplace
transform.
- Write 2 properties of Laplace
transformations.
- Give an example for forced response
- Define source – free response
- Define Zero- Input response
- Define Zero – State response
- Write the boundary conditions for the inductance
- Write the boundary conditions for the capacitance
- What are the effects of switching on resistor
- Write the steps to be involved in the determination
of initial conditions
- Define damping ratio?
- Sketch the current given by i(t)= 5 – 4 e-20t
- What are the three cases involved in R-L-C transients
- Distinguish between free response and forced response
- Define a time constant?
Part-B
1. (i)Draw the
DC response of R-L circuit and derive the power equation of resistor and
inductor. . (6)
(ii)Draw the DC response of R-C circuit and
derive the power equation of resistor and capacitor. . (6)
2. Draw the DC
response of R-L-C circuit and derive the equation of over damped, under damped
and critically damped. (12)
3. The circuit
shown in figure consists of resistance, inductance and capacitance in
Series with a 100 V constant source. When
the switch is closed at t = 0, find the
Current transient. (12)
4. Draw the
sinusoidal response of R-L circuit and determine the current equation.(12)
5. Draw the
sinusoidal response of R-C circuit and determine the current equation(12)
6. Draw the
sinusoidal response of R-L-C circuit and determine the current equation
(12)
7. The circuit
consisting of a series RLC elements with R=10 Ω, L=0.5 H and C=200 µ₣ has a
sinusoidal voltage V=150 sin (200t+ Ф).If the switch is closed when Ф =30•
.Determine the current equation. (12)
8.(i) The
circuit consists of series RL elements with R= 150 Ω and L=0.5H. The switch is
closed when Ф=30•.Determine the resultant current when voltage=150
cos (100t+ Ф) V.
(6)
(ii) Write short notes on transient analysis. (6)
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