Tuesday, 15 September 2015

ELECTRICAL MACHINES-II for backlog management system

ELECTRICAL MACHINES-II
II/IV B.TECH II-SEMESTER

UNIT-I:

1.  Explain the Constructional Details of Transformer?
2.  Explain working principle of Transformer and also write the applications
     Of Transformers?
3.  Derive the EMF Equation of the Transformer?
4.  Explain why hystersis and eddy current losses occurs in a transformer?

UNIT-II:

1. What are the advantages and disadvantages of autotransformers?
2. Draw the phasor diagrams corresponding to parallel operation of transformers
     With equal voltage ratio?
3. Draw the phasor diagrams corresponding to parallel operation of transformers with 
     Un-equal voltage ratio ?
4. Explain why open circuit test is conducted on transformer. Give related
     Calculations
5. Explain why short circuit test is conducted on transformer. Give related
     Calculations
UNIT-III:

1. List out the advantages and disadvantages of a bank of 3, 1-phase transformers
     to single 3-phase transformers.
2. Explain the function of center-tapped reactor in on load tap changer.
3. With neat phasor diagram, explain the voltage regulation of three-phase
    transformer.
4. Discuss in detail the effect of
       i. current harmonics,
      ii. Voltage harmonics on the performance of three phase transformers.

UNIT-IV:

1. Does the induction motor have any similarities with the transformer? Compare
     the similarities and differences between them.
2.  Show that a rotating magnetic field is produced in the air-gap, when a balanced 
      Three-phase ac supply is given to the stator of a 3-phase induction motor. Justify 
      Your claim with necessary mathematical equations
3. With the help of neat sketch, explain the constructional features of a
     three-phase   induction motors.

4. Explain the differences between sq. cage IM & Slip ring IM.

UNIT-V


1. Explain the torque development process in an induction motor and its dependence
    on rotor slip
2. Draw and explain the phasor diagram of 3-phase induction motor.

3. Discuss the phenomenon of crawling in an induction motor

4. Discuss the phenomenon of cogging in an induction motor


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