US 5,294,374 A · Electrical overstress materials and method of manufacture

Abstract

This invention provides a method of preparing an electrical overstress material having a nonlinear resistance which declines sharply in response to an electric field exceeding a clamping voltage so as to be able to shunt out transient surges which method comprises using an adhesive binder, for example a silicone rubber or a ceramics dispersion, and thorough mixing therein of small conductive, and optionally semiconductive particles, for example nickel particles of various morphologies and silicon carbide particles respectively, followed by molding under pressure and curing. The invention is also directed to the electrical overstress material itself which has excellent strength and integrity as well as survivability from multiple surges and has multiple applications in, for example, electrical outlet strips and power cables. The invention is also directed to a power outlet strip comprising a plurality of surge arresting elements composed of the electrical overstress material of the invention.

Claims20

Dependent claims

A method of preparing a nonlinear electrical resistance material useful for protecting electrical equipment against transient surges which method comprises the steps of:

composing a mixture comprising a curable adhesive fluid binder of substantially insulative electrical resistivity, and electrical filler material comprising conductor particles having an applied coating of not less than 70 Angstroms nor more than 1 Micron, and semiconductor particles having no applied coating, wherein the electrical filler material is present in an amount from 15 to 97 volume percent of said mixture;
mixing said mixture until a uniform consistency is obtained of said particles in said binder and the particles are substantially all coated with said binder;
molding said mixture under pressure into a shaped, coherent self-supporting material to pack the particles closely together with interparticle spaces filled with binder and substantially free of voids to provide a material having a clamping voltage such that it presents substantially an open circuit to voltage surges below said clamping voltage, said material being capable of maintaining said clamping voltage after repeated surges in excess of said clamping voltage, and said material being capable of repeatedly conducting said surges in excess of said clamping voltage by electron transport.

Dependencies are inferred from the claim text.

Electrical overstress materials and method of manufacture

Life of this patent

Electrical overstress materials and method of manufacture

Life of this patent

Abstract

Claims20