Electric fuse capable of interrupting small overload currents by series multibreaks
US4054858A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 19, 1976 |
| Grant date | Oct 18, 1977 |
| Priority date | — |
| Expiry date | Oct 19, 1996 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H85/38
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The fusible element of a fuse that needs series multibreaks for interrupting small currents is provided with a shunt current path including an arc gap in the center region thereof. That current path does not normally carry any current on account of the presence of the arc gap in it. The shunt current path shunts a portion of the fusible element including a so-called M-effect causing overlay. When that overlay becomes operative it causes formation of an arc gap in the fusible element which, in turn, causes a voltage to appear across the arc gap. When that voltage is sufficiently high the arc gap breaks down. The ensuing arc current is too small to allow formation of series breaks in the fusible element. The fusible element or the above shunt thereof are provided with beads that evolve gases under the action of the arc. These gases are directed to the points of junction of the fusible element and its shunt and due to this artificial gap contamination by hot gases the arc current becomes sufficiently high to produce series breaks in the fusible element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.