How do I apply Faraday's Law of Induction to my project?

[AlmostHandy]

Hey there everyone.

I'm working on a project and I want to incorporate a small version of Faraday's Linear Shake Flashlight.

I'm stuck on how to apply Faraday's formula to the variables that I have.

The formula wants "flux". How to I calculate the flux of my magnets? I know the pull strength and I know the "Gauss" of the magnets. Can I calculate the flux from those values?
As I understand it, the formula wants to know the speed at which the flux goes from minimum to maximum. So, the faster the magnet moves, then the more voltage is created? Is that right?

Here are the materials I'll be using.

The magnets are NdFeB, N42 grade, 1/4"X1/4" Cylinders with a Ni-Cu-Ni coating. They are rated at 13200 Gauss, and 5.59Lbs Pull Force.

The tube for the coil will be a section of plastic drinking straw with a wall thickness of 0.15MM.

I'll be using 30 AWG Enameled Magnet Wire for the windings.

Is there a way to ballpark the voltage generated with a certain number of coil windings and the variables I've described?

I'm not really looking for the "answers", but rather looking for help in trying to understand how to figure it out on my own. Thank you for any advice and help you can give.

 

[m.s.j]

For induced voltage in a simple rotating loop with w ( w = 2пf rotating velocity) in a uniform magnetic field, we can write:

Eind =dØ/dt (Faraday's low)

or

Eind = Ø_max . w. sin w

In the other hand regarding to mentioned Ø_max, applying Ampere’s law, the total amount of magnetic field induced will be proportional to the amount of current flowing through the conductor wound with N turns around the ferromagnetic material. Since the core is made of ferromagnetic material, it is assume that a majority of the magnetic field will be confined to the core. The path of integration in Ampere’s law is the mean path length of the core, l_c. The current passing within the path of integration Inet is then Ni, since the coil of wires cuts the path of integration N times while carrying the current i. Hence Ampere’s Law becomes

H.l_c=Ni

In this sense, H (Ampere turns per meter) is known as the effort required to induce a magnetic field. The strength of the magnetic field flux produced in the core also depends on the material of the core. Thus,

B= µ.H
Ø=B.A


B = magnetic flux density (webers per square meter, Tesla (T))
µ= magnetic permeability of material (Henrys per meter)
H = magnetic field intensity (ampere-turns per meter)
A= cross sectional area throughout the core

Taking into account past derivation of B,

Ø = ( µ.N.i.A)/l_C


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Creative thinking is breezy, Then think about your surrounding things and other thought products. http://electrical-riddles.com

 

[AlmostHandy]

Thank you, m.s.j.,

I've read and re-read your reply, and I really appreciate you taking the time to write that, but it's just way over my head. I get bits and pieces of it, but other parts just whiz right by.

I'll be specific. What does "2пf rotating velocity" mean?
What does the "d" in "dØ/dt" mean?
In "Eind = Ømax . w. sin w", are the periods representing multiplication?Also, I'm still confused as to how to get the "Flux" value of my magnets. Can I obtain that number from the data I have? Was that part of those formulas you gave me and I just can't see it?

Thanks again for all your help.

 

[MrBanks]

I just wrote you a really long post on what to do and I tried to submit it, but for some reason it said it logged me out and it deleted all of it. I'm pissed lol and I don't have time to write it all over. So here is a hint.

1 T = 10⁴ Gauss ==> Strength of your magnetic field B

Bflux = B*A cos(theta) ==> This is a simplified case and theta = 0 for you and A is the area of your loop; units are T * m².

Bflux max is when the north pole of your magnet is right outside the loop of wire ( Bflux max = BA) and Bflux min is when the south pole is right out side the loop (Bflux min = -BA).

I had much more written, but like I said it got deleted. So let me know if this was any help.

 

[m.s.j]

Dear AlmostHandy,

1- W=2пf=2п/T where T (sec.) is the period of rotating.
2- Meaning of d is mathematic differential (d…/dt)
3- Refer to 1 above
4- Note to formula Ø = ( µ.N.i.A)/lC

What is your education background?



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Creative thinking is breezy, Then think about your surrounding things and other thought products. http://electrical-riddles.com

 

[ploplopscoopy]

M.s.j seems to be very current and knowledgeable about all of the physics involved in Faraday's electromagnetic induction principles. I want to ask him whether it would be even theoretically possible to build Faraday generators into the harnesses of a team of sled dogs. If so, could the current be stored in battery packs and saved for future use? And finally, could something similar be built for a horse in a rescue sanctuary? Could the current be retrieved through the electric fence and used to defray the organization's light bill? Please do not tell me how to build this contraption. Answer "possible in theory", "totally impossible", or "too many variables to tell". Thank you!