Concept explainers
(a)
The effect on the induced emf of a generator if the flux per pole is doubled.
(a)
Answer to Problem 12SP
Solution:
Doubled
Explanation of Solution
Given data:
The flux per pole is doubled.
Formula used:
The induced emf of the generator is expressed as
Here,
Explanation:
Consider the expression for induced emf of the generator at its initial condition:
Consider the expression for induced emf of the generator when flux per pole is doubled:
From equation (1) and (2),
Understand that the magnetic flux per pole is doubled. Hence, magnetic field should be doubled.
Substitute
Solve for
Conclusion:
Therefore, if the flux per pole is doubled, the induced emf of a generator doubles as well.
(b)
The effect on the induced emf of a generator if the speed of the armature is doubled.
(b)
Answer to Problem 12SP
Solution:
Doubled
Explanation of Solution
Given data:
The speed of the armature is doubled.
Formula used:
The induced emf of the generator is expressed as
Here,
Explanation:
Consider the expression for induced emf of the generator at its initial condition:
Consider the expression for induced emf of the generator when the speed of the armature is doubled, assuming the doubling of speed will not have much effect on the cosine term of the induced emf for small speed. Therefore,
From equation (3) and (4),
Substitute
Solve for
Conclusion:
Therefore, if the speed of the armature is doubled, the induced emf of a generator will also be double.
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Chapter 33 Solutions
Schaum's Outline of College Physics, Twelfth Edition (Schaum's Outlines)
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