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APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY

FIRSTSEMESTER M.TECH DEGREE EXAMINATION, JUNE/JULY 201 8

Branch: Electrical and Electronics Engineering

Stream(s) :
| ١ Power Control and Drives
2. Electrical Machines
3. Power systems

Course Code & Name: OIEE6301: MODELLING OF ELECTRICAL MACHINES

Answer any two full questions from each part
Limit answers to the required points.

Max. Marks: 60 Duration: 3 hours

PARTA

1. a. Write any four conventions to be followed to get the two pole model. (2)

b. Derive the expression for transformer and speed voltages in the armature
alongthed-axis. (4)
c. Draw the basic two pole machine representation for the following machines:

i) DC Compound Machine ii) Synchronous
Machine with damper bars
(3)

2. a. Write the voltage equations for Kron's primitive machine in ma&ix form (5)

b. Derive electrical torque expression of Kron's primitive machine in terms of
reluctance and show that no torque is produced by interaction between flux
and current on the same axis. (4)

3. a. Explain transformations for currents between a rotating balanced three phase
(9, 2, ©) winding to a rotating tweo phase (u,f) winding. Assume equal number
of turns. (6)

b. Explain the term invariance of power as applied to electrical machines. Show
the power invariance is maintained under this transformation. (3)