Abstract: The switch contacts of a MEMS relay for a circuit interrupter are coated with a thin layer of liquid metal, and the MEMS relay is disposed in a sealed enclosure containing a gas medium. The gas medium provides an environmentally desirable alternative to sulfur hexafluoride (SF6), prevents oxidation of the liquid metal coating the relay switch contacts, and has sufficient dielectric strength in order to prevent current flow after separation of the switch contacts.

Abstract: A power fuse for protecting an electrical load subject to transient load current cycling events in a direct current electrical power system is provided. The power fuse includes at least one fuse element assembly that includes one or more substrates, one or more sets of weak spots, and a conductor. The weak spots are formed on the substrates, and the substrates are longitudinally spaced apart from one another along the conductor. The conductor is separately provided from the substrate and the weak spots. The conductor includes one or more strips of metal having no stamped weak spot openings therein and therefore avoiding thermal-mechanical fatigue strain in the conductor when subjected to the transient load current cycling events. The conductor includes connector sections that are attached to respective ones of the sets of weak spots, and extending sections coupling the connector sections.

Abstract: A printed fuse fabrication is provided. The printed fuse includes a low thermal conductivity ceramic substrate and a fusible element printed on the substrate. The fusible element printed on the substrate includes a series of portions of reduced printed thickness, defining weak spots for fusible operation of the fusible element, respectively separated by portions of increased printed thickness.

Abstract: A power fuse for protecting an electrical load subject to transient load current cycling events in a direct current electrical power system is provided. The power fuse includes at least one fuse element assembly that includes an elongated planar substrate, a plurality of fusible weak spots, and a conductor. The weak spots are formed on the substrate and are longitudinally spaced from one another on the substrate. The conductor is separately provided from the substrate and the weak spots. The conductor includes a solid elongated strip of metal having no stamped weak spot openings therein and therefore avoiding thermal-mechanical fatigue strain in the conductor when subjected to the transient load current cycling events. The solid elongated strip of metal includes coplanar connector sections that are mounted to respective ones of the weak spots and obliquely extending sections bent out of plane of the connector sections to extend above the substrate.

Abstract: The switch contacts of a MEMS relay for a circuit interrupter are coated with a thin layer of liquid metal, and the MEMS relay is disposed in a sealed enclosure containing a gas medium. The gas medium provides an environmentally desirable alternative to sulfur hexafluoride (SF6), prevents oxidation of the liquid metal coating the relay switch contacts, and has sufficient dielectric strength in order to prevent current flow after separation of the switch contacts.

Abstract: A power fuse for protecting an electrical load subject to transient load current cycling events in a direct current electrical power system is provided. The power fuse includes at least one fuse element assembly that includes an elongated planar substrate, a plurality of fusible weak spots, and a conductor. The weak spots are formed on the substrate and are longitudinally spaced from one another on the substrate. The conductor is separately provided from the substrate and the weak spots. The conductor includes a solid elongated strip of metal having no stamped weak spot openings therein and therefore avoiding thermal-mechanical fatigue strain in the conductor when subjected to the transient load current cycling events. The solid elongated strip of metal includes coplanar connector sections that are mounted to respective ones of the weak spots and obliquely extending sections bent out of plane of the connector sections to extend above the substrate.