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

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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