Current limiting device
US5614881A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 11, 1995 |
| Grant date | Mar 25, 1997 |
| Priority date | — |
| Expiry date | Aug 11, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H2033/163
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A current limiting device utilizing an electrically conductive composite material and an inhomogeneous distribution of resistance structure is disclosed. The inhomogeneous distribution is typically chosen so that at least one selected thin layer of the current limiting device has much higher resistance than the rest of the current limiting device. In the actual device, pressure is typically exerted on the composite material in a direction normal to the selected thin layer. During a short-circuit, it is believed that adiabatic resistive heating of this selected thin layer is followed by rapid thermal expansion which leads to either a partial or complete physical separation of the current limiting device at the selected thin layer which produces a higher over-all device resistance to electric current flow. Thus the current limiting device limits the flow of current through the short-circuited current path. When the short-circuit is cleared, the current limiting device regains its low resistance state allowing electrical current to flow normally. The current limiting of the present invention is reusable for many such short circuit conditions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.