Dual element fuse protector for electric circuits
US4184137A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 1977 |
| Grant date | Jan 15, 1980 |
| Priority date | — |
| Expiry date | Nov 14, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H85/055
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The dual element fuse of the present invention has at least one fusible element and at least one mass of heat softenable material; and that fusible element will respond to a short circuit to fuse and thereby assure opening of the circuit, whereas that mass of heat softenable material will respond to a long-continued relatively-low potentially-hurtful overcurrent to soften and thereby initiate opening of the circuit. That dual element fuse has a shunt element which shunts the mass of heat softenable material and which will fuse after that mass of heat softenable material has initiated opening of the circuit; and hence that shunt element will minimize arcing as that mass of heat softenable material initiates opening of the circuit. That shunt element has a current rating which is larger than the current rating of the mass of heat softenable material, so it will not fuse until after that mass of heat softenable material has initiated opening of the circuit; and that shunt element has a current-interrupting characteristic which has the same shape as that of the current-interrupting characteristic of the fusible element, so its clearing time will be similar to the clearing time of that …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.