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Electrical Engineering Electrical Machines Lab Experiments

Aim

Theory

Pretest

Procedure

Simulation

Posttest

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Aim

Theory

Pretest

Procedure

Simulation

Posttest

References

Feedback

Short Circuit Test on Three Phase Alternator

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Beginner

Intermediate

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The frequency of an alternator at a given RPM is determined by

a: number of turns of wire in the armature coil Explanation

Explanation

b: number of magnetic poles Explanation

Explanation

c: strength of the magnets used Explanation

Explanation

d: output voltage Explanation

Explanation

Which of the following will happen to the alternator frequency if the load is removed from a turbo generator, whose governor has a 3% speed droop?

a: it will remain unchanged Explanation

Explanation

b: it will decrease by approximately 3% Explanation

Explanation

c: it will increase Explanation

Explanation

d: it may increase or decrease Explanation

Explanation

Salient pole type rotors as compared to cylindrical pole type are

a: larger in diameter and smaller in axial length Explanation

Explanation

b: smaller in diameter as well as axial length Explanation

Explanation

c: larger in diameter as well as axial length Explanation

Explanation

d: smaller in diameter and larger in axial length Explanation

Explanation

In a synchronous machine, the field flux axis is ahead of the armature field is in the direction of rotation, the machine is working as

a: asynchronous alternator (B) Explanation

Explanation

b: asynchronous motor Explanation

Explanation

c: synchronous motor Explanation

Explanation

d: synchronous alternator Explanation

Explanation

When a generator designed for operation at 60 Hz is operated at 50 Hz

a: operating voltage must be derated to (50/60) of its original value Explanation

Explanation

b: operating voltage must be derated to (50/60)2 of its original value Explanation

Explanation

c: kVA rating can be upgraded to (60/50) of the rated value Explanation

Explanation

d: the generator will not take any load. Explanation

Explanation

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