| Author | Message | ||
     Ryan Somebody |
Is there any way to build a magnetometer (gauss meter) using a multimeter and coil. I was thinking of using a reciprocating motor to move the coil over a magnet and measure the voltage generated (or vice-versa) Also, do you know of a way to convert microhenries/henries into gauss/tesla? I need to figure out how strong a 1600 microhenry coil is in comparison to neodymium magnets (such as the ones on your site). The inside diameter of the coil is 7/8" if that helps. Thanks for the help and keep up the great work! | ||
| Simon Quellen Field (Sfield) |
Things like neodymium-iron-boron magnets are measured in MegaGaussOersteds (total energy product). To compare them to a coil, we can use the way we describe the total energy product of a coil. So we use ampere-turns per cubic meter. One MegaGaussOersted is 7.96 ampere-turns per cubic meter. GaussOersteds is a way of describing the product of the number of Gauss in the magnet times the number of Oersteds in the magnet. A Gauss is a measure of the magnetic flux density. It is one Maxwell per square centimeter. One Gauss will induce an electromotive force of 0.00000001 volts per linear centimeter of wire moving at right angles to the magnetic field at a rate of one centimeter per second. The Oersted is a unit of magnetic field intensity. An Oersted is 79.578 amperes per meter. If you have a single layer coil one meter long, and you run one ampere of current through that coil, you get a magnetic field strength of 1 ampere per meter. If the coil is 1.2566 centimeters long, and has the same 1 ampere of current in it, you have a magnetic field strength of one Oersted. The Neodymium-Iron-Boron magnets we sell in our catalog are called N48. This actually tests out to 46.2 MegaGaussOersteds. The field intensity is 6,730 Oersteds. The magnetic flux density is 6,870 Gauss. The product of these two is 46,235,100 GaussOersteds. To equal the field intensity of our magnets, you would need a single layer coil 1.2566 centimeters long, with 6,730 amps running through it. The hard part is to figure out how to get the flux density of the coil to be 6,870 Gauss. You would have to wind it around a material with a high permeability, and bend the whole thing into a "C" shape with the two poles close together. You may have to sharpen the points of the material to further concentrate the flux. Of course you would also have to cool the magnet somehow, or the 6,870 amps would cause it to explode. In practice, the coil would have many layers of windings, but that makes it harder to calculate. |
