Telephone circuit protector module having plural circuit grounding means
US5008772A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 24, 1990 |
| Grant date | Apr 16, 1991 |
| Priority date | — |
| Expiry date | Sep 24, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M3/18
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An improved telephone subscriber circuit protector module providing plural surge voltage and excess current protection elements including so-called sneak current protection. The module includes a three-element gas tube which protects against voltage surges in the range of 200 to 300 volts, and includes fail safe protection relative to the gas tube should the gas tube become non-conductive over its intended range of protection. The fail safe protection is thermally operated under the influence of high current. Secondary air gap protection supplements the operation of the gas tube in the event of gas tube failure, and is operative to ground momentary voltage surges in the area of 1500 volts. Separate sneak current protection employing heat coils are operative in a range below one ampere flow, and an alternate form provides for the opening of the subscriber side of the line rather than the grounding of it. All of the protective elements communicate with a common ground plane forming part of a ground assembly.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.