Maximum EMF in a rotating coil, in an AC generator?

In summary, the conversation discusses the concept of induced EMF in AC generators. It is mentioned that maximum magnetic flux flows through a coil when it is perpendicular to the magnetic field, and the flux is at a minimum when the coil is parallel to the field. It is then questioned why the EMF is at a maximum when the coil is parallel, and it is clarified that this is due to the rate of change of the flux, not the actual flux itself. Calculus and more information about the coil's rotation are necessary to compute the rate of change of the flux.
  • #1
ducks_1234
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Homework Statement


Im currently in my last year of high school, and I'm writing a report on AC generators. I've heard a number of different things from different sources. When the coil is perpendicular to the magnetic field, maximum magnetic flux is flowing through the coil. This is then at a minimum when the coil is parallel to the field.

EMF is induced when there is a rate of change of magentic flux through the loop. Why then is EMF at a maximum when the coil is parallel? i.e it was turned from being perpendicular to now being parallel.

Any help would be greatly appreciated!

Homework Equations


EMF = [tex]\Delta[/tex] ( [tex]\phi[/tex]2 - [tex]\phi[/tex]1) / [tex]\Delta[/tex] t


The Attempt at a Solution


My attempt is my failed understanding of the concept.


 
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  • #2
The EMF depends not on the flux through the coil, but instead on the rate of change of the flux through the coil, as you said.

When the coil is parallel the flux may be 0, but the rate of change of the flux is not zero. At that point, the flux is increasing at it's fastest rate. This is why the EMF is at its highest positive value at this point.

Does this make sense?

(In order to actually compute the rate of change of the flux in this problem, you'll need calculus, and more information about how the coil is rotating.)
 

Related to Maximum EMF in a rotating coil, in an AC generator?

1. What is the maximum EMF in a rotating coil in an AC generator?

The maximum EMF (electromotive force) in a rotating coil in an AC generator is determined by the speed of rotation, the number of turns in the coil, and the strength of the magnetic field. It can be calculated using the formula: E = NABωsin(ωt), where N is the number of turns, A is the area of the coil, B is the strength of the magnetic field, ω is the angular velocity, and t is time.

2. How does the maximum EMF change with the speed of rotation?

The maximum EMF in a rotating coil in an AC generator is directly proportional to the speed of rotation. This means that as the speed of rotation increases, the maximum EMF also increases. This is because a higher speed of rotation results in a higher frequency of the alternating current, which in turn leads to a higher maximum EMF.

3. How does the number of turns in the coil affect the maximum EMF?

The maximum EMF in a rotating coil in an AC generator is directly proportional to the number of turns in the coil. This means that as the number of turns increases, the maximum EMF also increases. This is because a higher number of turns results in a stronger magnetic field, which leads to a higher maximum EMF.

4. What happens to the maximum EMF when the strength of the magnetic field changes?

The maximum EMF in a rotating coil in an AC generator is directly proportional to the strength of the magnetic field. This means that as the strength of the magnetic field increases, the maximum EMF also increases. This is because a stronger magnetic field will induce a higher voltage in the coil, leading to a higher maximum EMF.

5. How does the frequency of the alternating current affect the maximum EMF?

The maximum EMF in a rotating coil in an AC generator is directly proportional to the frequency of the alternating current. This means that as the frequency increases, the maximum EMF also increases. This is because a higher frequency results in a higher rate of change in the magnetic field, leading to a higher maximum EMF.

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