Stabilized Permanent Magnets

PERMANENT MAGNETS used in apparatus often are subjected to demagnetization by current surges or stray fields. This weakens the magnet and changes the adjustment. Magnets usually are stabilized against such demagnetizing forces by partial demagnetization. Because, under this condition, the magnet operates at a point within the demagnetization curve quadrant, some other criterion of performance must be applied in magnet design. Under stabilized conditions it operates on a curve which is called a secondary demagnetization curve and can be derived from the major demagnetization curve:(a). By an applied demagnetizing magnetomotive force after magnetization in assembly. (b). By magnetization of the magnet before assembly in its magnetic circuit.