Patent ID: 6762388
Filing Date: 2004-07-13
Classification: H01H

Abstract:
A vacuum cartridge for an electrical protection apparatus, said cartridge comprising:an enclosure of substantially cylindrical shape symmetrical about a lengthwise axis and closed by two end plates; two contacts each having a contact surface and extending along the lengthwise axis inside the enclosure, wherein at least one of said contacts, called the movable contact, is connected to an operating mechanism and is mounted for sliding between a closed position of the contacts for enabling current to flow, and an open position wherein the contacts are separated for forming an electric arc in an arc formation zone therebetween; and means for producing a magnetic field parallel to the lengthwise axis in the arc formation zone, comprising: at least one conducting shield fitted around a periphery of at least one of the contacts, said at least one contact having an edge, said shield for withstanding an electric field arising from a recovery voltage imposed by a power system connected to the vacuum cartridge after interruption of power to the vacuum cartridge, thereby considerably reducing an electric field at the edge of said contact; at least one trench separating each shield from an associated one of said contacts, wherein at least part of a first ring, sectors of a first ring or studs located on a first contact surface of one of the contacts and facing at least part of a second ring, sectors of a second ring or studs located on a second contact surface of another of the contacts, for establishing electrical continuity across the contacts in the closed position, wherein said at least parts of said first and second rings, sectors of said first and second rings, or said first and second studs are located above said at least one trench.