GFCI with enhanced surge suppression
US7012500B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 19, 2004 |
| Grant date | Mar 14, 2006 |
| Priority date | — |
| Expiry date | Mar 19, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01C7/126
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An MOV element is physically and electrically connected to a heat sensitive material which changes from a low impedance path to a high impedance path, such as a spark gap, when the temperature of the MOV element rises to a temperature below that at which the MOV will enter into its thermal runaway state. More specifically, the heat sensitive material is located on a surface of the MOV and is electrically connected in series with the MOV. In operation, as the MOV gets hot, it heats the heat sensitive material. As the heat sensitive material gets hot, it starts to separate from the surface of the MOV to form a spark gap which is electrically connected in series with the MOV element to help dissipate excessive voltage. The heat sensitive material on the surface of the MOV element can be a coating of epoxy which cracks and/or breaks away, at least partially from the surface of the MOV element during the occurrence of a high voltage transient surge, or it can be a solder that sputters to form an arc path during the occurrence of a high voltage transient surge. In operation, when a GFCI is subjected to a high voltage transient surge above a certain magnitude, the heat sensitive material …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.