Reg No.:_ Name:

Max. Marks: 100

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(71103 Pages: 2

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
SEVENTH SEMESTER B.TECH DEGREE EXAMINATION(S), MAY 2019

Course Code: EE409

Course Name: Electrical Machine Design

PARTA
Answer all questions, each carries 5 marks.
What is meant by hot spot rating in electrical machines?
Compare the reluctance of slotted armature with that of smooth armature
surface.
Derive the output equation of DC machine.
Explain different types of cooling systems used in synchronous machines.
List out and explain the factors to be considered for selection of specific electric
loading in 3-phase induction motors.
State the main constructional differences between cage induction motor and slip
ring induction motor.
Explain synthesis method for computer aided design of electrical machines
Explain on few softwares used for designing electrical machines?
PART ‏تا‎
‎Answer any two full questions, each carries 10 marks.
Examine any four components of armature leakage flux.
Derive the relation between real and apparent flux densities.
Derive the output equation for 3 phase core type transformer.
Determine the dimensions of core and yoke for a 20017۷۸ 50112 single phase
core type transformer. A cruciform core is used with distance between adjacent
limbs equal to 1.6 times width of core laminations. Assume voltage per turn 14
V, maximum flux density 1.1Wb/m*, window space factor 0.32, current density
3A/mm/? and stacking factor 0.9. The net iron area is 0.56d? in a cruciform core
where d is the diameter of circumscribing circle and width of largest stamping is
0.85d.
Explain unbalanced magnetic pull in rotating electrical machines.
Derive the ratio of gross core area to area of circumscribing circle for a square

core of a transformer.

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Duration: 3 Hours

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