Magnetic Flux

The most important factor concerning the production of electricity is magnetic flux. Magnetic flux is what causes current flow. I should say that the change of magnetic flux is what causes current flow. The greater the magnetic flux and the faster the change of magnetic flux across a wire or a coil will determine the output. So a good understanding of magnetic flux will determine the success of your Alternator / generator.

Importance of Magnetic Flux

Being that the amount of voltage and current your alternator will produce is directly proportional to the gage of the wire (for amps), number of turns in your coil (for voltage), the amount of magnetic flux and the speed your coil cuts across that magnetic flux, you can see that knowing where the poles are located on your magnet is very important because the greatest concentration of magnetic flux in located at the poles.

Magnets are made from a variety of materials which determine greatly the strength of the magnet and will greatly effect the output of an alternator.
Click here to read about the most common magnetic materials. We will assume that you will be using NEODYMIUM MAGNETS because they are the strongest magnets produced to date. They have an incredible amount of magnetic flux for their size. NEODYMIUM MAGNETS are so strong that great care must be taken because they can crush fingers and even break bones.

Magnetic flux lines between two half spheres cut in half.

Above is a photo of two halves of a sphere magnet with a gap. The middle of the two magnets would be the best place to pass your wire or coil because of the concentration of magnetic flux.

Magnetic flux lines of a bar magnet. Differance between the magnetic flux of a bar magnet and a horse shoe magnet.

Above are a few examples of different magnetic shapes to get an idea of where the greatest concentration of magnetic flux.

The magnetic flux between two bar magnets.

The photo above shows two bar magnets next to each other with a gap and you can see the concentration of magnetic flux in the gap between the two.

The more flux involved the greater the effect on the wire or coil. Many times metal that attracts magnetic fields like soft iron will be placed behind the coil to attract the magnetic flux through the coil. The problem with this is that any conductor placed in a changing magnetic field will produce a current flow and cause an opposing magnetic field. These are called eddie currents. These eddie currents can adversely effect your design. This is why unless you are very learned in the design of magnetic circuits it is best to keep your design very simple.

I use the TI-89 Graphing Calculator for all my calculations
which has symbolic manipulation ability.

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