Demagnetizing, variable frequency

Abstract

A pair of demagnetizing coils, or more than two, and the article to be demagnetized is put in the coils. The demagnetizing is done by reversing the polarity in a series of steps in a cycle, and the current reduced in successive steps, to a point at or near zero. The cycle can be varied as to time period, and the number of steps within a cycle varied. The applied initial voltage can be adjusted or predetermined as to maximum value, with corresponding current values, and the number of steps predetermined within the cycle independently of the maximum voltage. The apparatus can be set in manual mode, wherein the cycle timer period and number of steps can be independently set, and to automatic mode, wherein the cycle time and number of steps are directly correlated. The polarity of the applied magnetic field is counter to that of the magnetized article, in the initial step, and additional resistances utilized in establishing greater or lesser magnitude of the magnetic field in the demagnetizing coils according to the initial polarity of the magnetized piece.

Dependencies are inferred from the claim text.