A plug-in contact assembly suitable for automatic transfer switches includes a contact holder, two moving contact pieces disposed apart from each other, a moving contact piece bracket and a biasing spring; the contact holder holds the moving contact piece bracket and the biasing spring therein; and the two moving contact pieces disposed apart from each other are held in place relative to the contact holder under the joint action of the biasing spring and the moving contact piece bracket; characterized in that, two ends of each moving contact piece are each provided with a moving contact thereon by means of welding.

A preparation method for a silver-metal oxide electrical contact material, comprising: (1) mixing a silver-containing precursor solution with a metal oxide precursor solution; (2) reacting a reducing agent with the mixed solution to obtain silver powder coated with a metal oxide precursor; (3) heat treating the silver powder in a non-reducing atmosphere to obtain the silver-metal oxide electrical contact material. A preparation device for a silver-metal oxide electrical contact material, a silver-metal oxide electrical contact material prepared by the preparation method, and an electrical contact prepared by the silver-metal oxide electrical contact material. The electrical contact material prepared by the preparation method is at nanoscale, significantly prolonging electrical endurance of the electrical contact.

A method of preparing silver-based oxide electrical contact materials with fiber-like arrangement, includes the following steps of: (1) uniformly mixing the silver-metal alloy powders and graphite powders and then ball-milling; (2) internally oxidizing the ball-milled powders; (3) sieving; (4) placing the sieved powders and the matrix powders into the powder mixer for mixing; (5) cold-isostatically pressing; (6) sintering; (7) hot-pressing; and (8) hot-extruding, thereby obtaining the silver-based oxide electrical contact material with fiber-like arrangement. The method of the present invention can obtain the silver-based oxide electrical contact material having neat fiber-like arrangement with no specific requirement on processing deformation, plasticity and ductility of the reinforcing phase. The production process in this method is simple and is easy to operate. Besides, there is no particular requirement on the equipment. The method greatly improves the performance of contact materials in aspects of resistance to welding and arc erosion, conductivity, and processing performance.

Fuse devices and electrical systems using the fuse devices are disclosed, with the fuse devices having internal components to cause a fuse blown event when the pre-determined current level is reached through the contacts. The internal components can comprise a levitation actuator that causes separation between one or more of the contacts as the current level approaches the predetermined level. This causes contact levitation and arcing, which increases the resistance at the contact being separated. This in turn causes the current through the contacts to seek another path that in the embodiments herein is a path to a pyro feature. The current activates the pyro feature, which causes the contacts to separate and puts the fuse device in “fuse blown” condition where currents can no longer flow through the contacts.

A method for producing a contact material on the basis of silver-tin oxide or silver-zinc oxide is disclosed. Tin oxide particles and/or zinc oxide particles are mixed with a powder of a metal different from silver. The mixture is heated beyond the melting point of the metal powder such that the tin oxide particles and/or zinc oxide particles are wetted with liquid metal. The mixture is exposed to an atmosphere containing oxygen and the metal is thereby oxidized. Thereafter, the mixture product formed by the oxidation step is embedded as a powder into a silver matrix. The product further relates to a corresponding contact material.

A preparation method for a silver-metal oxide electrical contact material, comprising: (1) mixing a silver-containing precursor solution with a metal oxide precursor solution; (2) reacting a reducing agent with the mixed solution to obtain silver powder coated with a metal oxide precursor; (3) heat treating the silver powder in a non-reducing atmosphere to obtain the silver-metal oxide electrical contact material. A preparation device for a silver-metal oxide electrical contact material, a silver-metal oxide electrical contact material prepared by the preparation method, and an electrical contact prepared by the silver-metal oxide electrical contact material. The electrical contact material prepared by the preparation method is at nanoscale, significantly prolonging electrical endurance of the electrical contact.

A plug-in contact assembly suitable for automatic transfer switches includes a contact holder, two moving contact pieces disposed apart from each other, a moving contact piece bracket and a biasing spring; the contact holder holds the moving contact piece bracket and the biasing spring therein; and the two moving contact pieces disposed apart from each other are held in place relative to the contact holder under the joint action of the biasing spring and the moving contact piece bracket; characterized in that, two ends of each moving contact piece are each provided with a moving contact thereon by means of welding.

A method for producing a contact material on the basis of silver-tin oxide or silver-zinc oxide is disclosed. Tin oxide particles and/or zinc oxide particles are mixed with a powder of a metal different from silver. The mixture is heated beyond the melting point of the metal powder such that the tin oxide particles and/or zinc oxide particles are wetted with liquid metal. The mixture is exposed to an atmosphere containing oxygen and the metal is thereby oxidized. Thereafter, the mixture product formed by the oxidation step is embedded as a powder into a silver matrix. The product further relates to a corresponding contact material.

Fuse devices and electrical systems using the fuse devices are disclosed, with the fuse devices having internal components to cause a fuse blown event when the pre-determined current level is reached through the contacts. The internal components can comprise a levitation actuator that causes separation between one or more of the contacts as the current level approaches the predetermined level. This causes contact levitation and arcing, which increases the resistance at the contact being separated. This in turn causes the current through the contacts to seek another path that in the embodiments herein is a path to a pyro feature. The current activates the pyro feature, which causes the contacts to separate and puts the fuse device in fuse blown condition where currents can no longer flow through the contacts.

Problem To maintain a low internal resistance value and adjust spring characteristics by using a movable contact made of a multilayered material. Means for Solving Problem A thermosensitive pellet-type thermal fuse includes, in an interior of a cylindrical case having electrical conductivity, a thermosensitive pellet that melts or softens at a temperature, a strong compression spring configured to press the thermosensitive pellet, an insulating cover closing the cylindrical case, a weak compression spring abutting against the insulating cover, a first lead extending through the insulating cover and including an inner end as a fixed contact, a movable contact electrically connecting to the first lead and the cylindrical case, a sealing resin provided surrounding a portion of the first lead and covering an outer end portion of the insulating cover, and sealing an open end portion of the cylindrical case, and a second lead disposed at one end of the cylindrical case. The movable contact includes a conductive base material and a conductive member covering a predetermined surface of the conductive base material. The conductive member is provided to contact portions with the fixed contact and an inner wall surface of the cylindrical case, and is made of a material having a Young's modulus and a rigidity different from those of the conductive base material.