The BH data for a magnet provided by my customer doesn't look like a normal BH curve. Could it be based on intrinsic B?
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The discussion below can be found at the following link: <a target=_blank href="http://www.magnetsales.com/Design/DesignG_frames/frame_dgbod2.htm">http://www.magnetsales.com/Design/DesignG_frames/frame_dgbod2.htm</a>http://www.magnetsales.com/Design/DesignG_frames/frame_dgbod2.htm When plotting a B-H curve, the value of B is obtained by measuring the total flux in the magnet (ø)and then dividing this by the magnet pole area (A) to obtain the flux density (B=ø/A). The total flux is composed of the flux produced in the magnet by the magnetizing field (H), and the intrinsic ability of the magnet material to produce more flux due to the orientation of the domains. The flux density of the magnet is therefore composed of two components, one equal to the applied H, and the other created by the intrinsic ability of ferromagnetic materials to produce flux. The intrinsic flux density is given the symbol Bi where total flux B = H + Bi, or, Bi = B - H. In normal operating conditions, no external magnetizing field is present, and the magnet operates in the second quadrant, where H has a negative value. Although strictly negative, H is usually referred to as a positive number, and therefore, in normal practice, Bi = B + H. It is possible to plot an intrinsic as well as a normal B-H curve. The point at which the intrinsic curve crosses the H axis is the intrinsic coercive force, and is given the symbol Hci. High Hci values are an indicator of inherent stability of the magnet material. The normal curve can be derived from the intrinsic curve and vice versa. In practice, if a magnet is operated in a static manner with no external fields present, the normal curve is sufficient for design purposes. When external fields are present, the normal and intrinsic curves are used to determine the changes in the intrinsic properties of the material. |
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