Apparatus for detecting arcing faults and ground faults in multiwire branch electric power circuits
US6014297A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 1999 |
| Grant date | Jan 11, 2000 |
| Priority date | — |
| Expiry date | Mar 16, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/105
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A multiwire branch circuit including two line conductors and a grounded, common neutral conductor is protected by a two pole circuit breaker connected to independently interrupt overcurrent conditions in the two ungrounded line conductors. Three separate protection circuits provide arc fault protection for each of the ungrounded line conductors and ground fault protection for all three conductors. The arc fault detectors use the bimetal of the thermal-magnetic trip device for the associated line conductor for current detection, and therefore, are individually referenced to the associated line voltage. Hence, the outputs of the arc fault detectors are electrically isolated from each other and from the output of the ground fault detector, but operate a common trip circuit to simultaneously open both poles of the two pole circuit breaker. The arc fault detectors have separate isolated power supplies. The ground fault detector is powered by a supply which is energized if either of the ungrounded line conductors is energized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.