Power generated from magnet and coil

[xonsniper4]

Hey guys,
I'm an engineering student and for my project i am planning to use a power generator based on magnet and coil like those hand power shake flashlights.

I am using gauge 45 AWG copper wires (0.051816mm) and coiled to have 200 coils. The coil size will be 2.5cm. The magnet i am using will be N40 Neodymium cylindrical magnet sized 0.5'' x0.5'' with rated residual flux density of 1.25T.

I am hoping you guys can give me some advice in calculating the power generated from this setup.

Things i tried: I used Faraday's law to find voltage. After that, i used resistivity of copper and found the resistance of the wire then used P=V^2/R to try finding power but it seem to be too high to be real.

Thanks

PS: this is not a homework problem. Its a design project and we decide to use this system. We are mechanical engineering students that's why we couldn't find any professors to help us.

 

[Simon Bridge]

Welcome to PF;
So you have a permanent magnet that can slide through a coil - the idea being that you shake it or tip it.
Please note: a "design project" is homework. You have to do the designing yourself.

The sort of calculations you need to do will depend on the parameters of the design. What is it you need to design exactly? i.e. do you need to design the device to produce a specific output for a specific input - to specific tolerances?

Maybe it has to charge a battery to some level (i.e. so it runs an LED for a few hours) in some reasonable amount of time (i.e. before your arm gets too tired)?

When you know the design parameters, the rest will get a lot clearer.

I suspect you are best served by some sort of approximation.

 

[berkeman]

Hey guys,
I'm an engineering student and for my project i am planning to use a power generator based on magnet and coil like those hand power shake flashlights.

I am using gauge 45 AWG copper wires (0.051816mm) and coiled to have 200 coils. The coil size will be 2.5cm. The magnet i am using will be N40 Neodymium cylindrical magnet sized 0.5'' x0.5'' with rated residual flux density of 1.25T.

I am hoping you guys can give me some advice in calculating the power generated from this setup.

Things i tried: I used Faraday's law to find voltage. After that, i used resistivity of copper and found the resistance of the wire then used P=V^2/R to try finding power but it seem to be too high to be real.

Thanks

PS: this is not a homework problem. Its a design project and we decide to use this system. We are mechanical engineering students that's why we couldn't find any professors to help us.

Welcome to the PF.

One keyword that you can use to look for references is "Dynamo". Here's the link to the wikipedia page, which has a number of references at the end of the article to help you find design equations:

http://en.wikipedia.org/wiki/Dynamo

 

[xonsniper4]

I actually have to design a energy harvesting floors. Magnetism is just one of my ideas. I just need to find out how to calculate the power it can produce from the coil. how it works is the person walks on the tile and the magnet goes through the coil generating electricity. We might be using a battery or a capacitor to hold the charge to power LED lights. Just need to find out how to calculate the power it produces.

 

[rezeew]

Hi there,

Great to hear that you are exploring power generation using magnets and coils for your project. This is a very interesting and practical application of electromagnetic principles.

Firstly, I would like to commend you for using Faraday's law to calculate the voltage induced in the coil. This is the correct approach as the changing magnetic field from the moving magnet will induce an electric field in the coil.

To calculate the power generated, you will need to take into account the resistance of the wire and the current flowing through it. As you have mentioned, you have already calculated the resistance of the wire using its resistivity and length. However, to find the current, you will need to consider the magnetic flux density of the magnet, the area of the coil, and the speed at which the magnet is moving.

The current induced in the coil can be calculated using the formula I = BANv, where B is the magnetic flux density, A is the area of the coil, N is the number of turns in the coil, and v is the velocity of the magnet. Once you have the current, you can use the power formula P = VI to calculate the power generated.

It is important to note that the power generated will also depend on the efficiency of your system, which includes factors such as the spacing between the magnet and coil, the quality of the materials used, and any losses due to friction or resistance.

I hope this helps you in your project. Best of luck!