About Magnets
The method used to magnetize a part is to send a very short (perhaps a thousandth of a second) pulse of electric energy at very high voltage and current, through a fixture which converts the electrical pulse into a magnetic pulse. Whenever electric current flows through a wire, a magnetic field is set up in a circular field (no poles) around the wire, the direction of the field being at right angles to the direction of current. By properly shaping wire conductors, often with steel (or other magnetically permeable) pole material used both to support the wires, and also to help concentrate and direct the magnetic flux, a fixture can be made which holds the part and causes it to assume the required magnetic pole pattern. The currents in the fixture are usually so high that it would overheat, burn out its insulation, and even melt or vaporize the wire, if the power were allowed to be on too long. The magnetization of the part is accomplished in an extremely short time, once the required coercive field is attained (millionths of a second), and so the field does not need to be present very long. This is fortunate, since otherwise the extremely high currents needed to produce the required field could not be achieved in the space available.

If a number of magnets are placed together, they tend to line up end-to-end. In a magnet, individual atoms (or small groups of atoms) also tend to line up within small regions called DOMAINS, producing tiny local magnetic regions. In an unmagnetized part, these domains exist everywhere, but they have fields which point in different directions, and they cancel each other out so that the average resulting field is zero.

Show printable page
[home] [products] [services] [articles] [catalog] [request quote] [links] [email]
Copyright © 2003 Oersted Technology II Inc.
Send us email:
NEW! We now sell magnetic viewing film
Find out more . . .