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### Transcript of PART A Questions BTL Domain Level - 200V DC motor has an armature resistance of 0.06© and...

• UNIT I DC MACHINES

Three phase circuits, a review. Construction of DC machines Theory of operation of DC

generators Characteristics of DC generatorsOperating principle of DC motors Types of

DC motors and their characteristicsSpeed control of DC motors Applications.

PART A

Q.No. Questions BTL

Level

Domain

1. List the types of DC Motors. Give any difference between them. BTL 1 Remembering

2. Name the different methods of excitation of generator? BTL 1 Remembering

3. Quote (i) Faradays law of Electro magnetic Induction (ii) Lenz

Law.

BTL 1 Remembering

4. Define the terms (i) Electric Motor (ii) Electric Generator. BTL 1 Remembering

5. Tell the different techniques used for the speed control of DC

Series Motor?

BTL 1 Remembering

6. Examine the main elements of a DC Machine? BTL 1 Remembering

7. Express the formula for the armature torque produced by the motor

for DC Series Motor and DC Shunt Motor.

BTL 2 Understanding

8. Summarize the different characteristics of DC Generator. BTL 2 Understanding

9. Predict the formulae for the voltage equation of a DC Motor. BTL 2 Understanding

10. Discuss the formulae for the generated emf of a DC Generator. BTL 2 Understanding

11. A 200V DC motor has an armature resistance of 0.06 and series

field resistance 0f 0.04. If the motor input is 20kW, Calculate the

back emf of the motor and power developed in armature.

BTL 3 Applying

12. A DC motor operates from a 240V supply. The armature resistance

is 0.2. Solve and obtain the back emf when the armature current

is 50A.

BTL 3 Applying

13. A 6 pole wave connected armature has 300 conductors and

produces the flux per pole 0.02 Weber. The Generated emf is 600

Volts. Discover the speed of the Generator

BTL 3 Applying

• 14. Point out how the star connected system is differentiated with delta

systems.

BTL 4 Analyzing

15. In speed control of DC Shunt Motor analyze how the armature

control method is differentiated from field control method.

BTL 4 Analyzing

16. Classify the different method of speed control of DC Shunt motor? BTL 4 Analyzing

17. Summarize the following terms (i) Commutator (ii) Brushes and

Bearing (iii) Magnetic Frame (iv) Pole Core of DC Machine.

BTL 5 Evaluating

18. Explain the significance of back e.m.f in Motor? BTL 5 Evaluating

19. Compose any two applications of DC Shunt Motor and Series

Motor.

BTL 6 Creating

20. Develop the open circuit characteristics of DC Generator. BTL 6 Creating

PART B

1. (i)With neat diagram describe the construction and working of DC

Generator. (7)

(ii) Examine the theory and principle of operation of a DC

Generator. (6)

BTL 1 Remembering

2. Quote the following characteristics of DC Generator and explain

each (i) Open Circuit Characteristics (i) Internal Characteristics (iii)

External Characteristics. (13)

BTL 1 Remembering

3. (i) Describe the speed control of DC series motor by flux control

technique. (7)

(ii) Explain the Ward Leonard Method for the speed control of DC

Motor. (6)

BTL 1 Remembering

4. (i) A separately excited Dc generator running at 1000rpm supplied

110A at 220V to a resistive load. If the load resistance remains

constant, what will the load current if the speed is reduced to

800rpm? Armature resistance is 0.02. Field current is unaltered.

Assume a voltage drop of 1V per brush. Ignore the effect of

armature reaction. (7)

(ii) Briefly explain the load characteristics of different types DC

Generator (i) DC Series Generator (ii) DC Shunt Generator (iii) DC

Compound Generator. (6)

BTL 1 Remembering

• 5. A 250 V Shunt motor takes the total current of 20 A. The shunt field

and armature resistances of 200 and 0.3 ohm respectively.

Estimate (i) Value of back emf (ii) Gross mechanical power in

armature. (13)

BTL 2 Understanding

6. The armature of a 6-pole, 600 rpm lap wound generator has 90

slots. If each coil has 4-turns. Estimate the flux per pole required to

generate emf of 288 Volts. (13)

BTL 2 Understanding

7. Estimate the emf generated by 4-pole wave wound generator having

65 slots with 12 conductors per slot when driven at 1200 rpm. The

flux per pole is 0.02 Weber. (13)

BTL 2 Understanding

8. How the DC Motor can be classified ? Illustrate the following types

of motors (i) DC Series Motor (ii) DC Shunt Motor (iii) DC

Compound Motor. And also write the voltage equation and also

applications of each. (13)

BTL 2 Understanding

9. (i) Demonstrate the principle of operation of DC Motor. And also

explain (i) Faradays law of Electro Magnetic Induction (ii)

Flemings Left Hand Rule (iii) Force Equation (iv) Back emf. (13)

BTL 3 Applying

10. Differentiate the following methods for the speed control of DC

Motor (i) Armature Control Method (7)

(ii) Field Control Method. (6)

BTL 4 Analyzing

11. With a neat sketch, explain the construction and working of DC

Motor and also explain each parts. (13)

BTL 4 Analyzing

12. In three phase circuit analyze how the star connection is

differentiated with the delta connection and explain with suitable

diagram. (13)

BTL 4 Analyzing

13. (i) Evaluate the emf equation of DC generator. (7)

(ii)Summarize from the first principle an expression for the torque

developed in DC motor. (6)

BTL 5 Evaluating

14. Compose the following characteristics (i) Speed versus Torque (ii)

Torque versus Current (iii) Speed versus Current for the following

motors such as, DC Series Motor, DC Shunt Motor, DC Compound

Motor. (13)

BTL 6 Creating

• PART C

1. Create the circuit for the speed control of DC Series and Shunt

Motor and also sketch the output plot for

(i) Flux Control Method

(ii) Armature Control Method

(iii) Voltage Control Method. (15)

BTL 6 Creating

2. In detail explain about the classification of DC generator with

necessary circuit diagram. Arrive at voltage and current relationship

for each type (15)

BTL 5 Evaluating

UNIT II TRANSFORMERS

Introduction Single phase transformer construction and principle of operation EMF equation of

transformer Transformer no-load phasor diagram Transformer on-load phasor diagramEquivalent circuit

of transformerRegulation of transformerTransformer losses and efficiencyAll day efficiencyauto

transformers.

PART A

Q.No. Questions BTL

Level

Domain

1. List out any four applications of transformers. BTL 1 Remembering

2. Define regulation in a transformer. BTL 1 Remembering

3. Quote the term Efficiency of a transformer. BTL 1 Remembering

4. Describe the voltage transformation ratio equation for (i) Step up

Transformer (ii) Step down Transformer.

BTL 1 Remembering

5. Examine how the Efficiency is distinguished with the All Day

Efficiency of a transformer.

BTL 1 Remembering

6. Identify the reason for transformer is rated in kVA instead of kW?

BTL 1 Remembering

7. What is meant by transformer ? With suitable diagram give the different

elements of single phase transformer.

BTL 2 Understanding

8. Distinguish between core and shell type transformer. BTL 2 Understanding

• 9. A 1 auto transformer has a voltage ratio 320V:250V and supplies a

load of 20kV at 250V. Assuming an ideal transformer, estimate the

current in each section of winding (primary and secondary) and the

current in the common part of the windings.

BTL 2 Understanding

10. Differe