magnet concept

Am area of the magnet, is the cross sectional areal of the magnet perpendicular to the central flux line, measured in sq.cm. at any point along its length. In design, am is usually considered the area at the neutral section of the magnet. 

B Magnet induction, is the magnetic field induced by a field strength, H, at a given point. It is the vector sum, at each point within the substance, of the magnetic field strength and resultant intrinsic induction. Magnetic induction is the flux per unit area normal to the direction of the magnetic path. 

Bd Remanent induction, is any magnetic induction that remains in a magnetic material after removal of an applied saturationg magnetic field, Hs. (Bd is the magnetic induction at any point on the demagnetization curve; measured in gauss .

BdHd Energy product, indicates the energy that a magnetic material can supply to an external magnetic circuit when operating at any point on its demagnetization curve; measured in megagauss-oersteds. 

BH Maximum energy product, is the maximum product of (BdHd) which can be obtained on the demagnetization curve. 

Br Residual induction (or flux density) , is the magnetic induction corresponding to zero magnetizing force in a magnetic material after saturation in a closed circuit; measured in guass.