Current fault protection system
US4812943A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 24, 1987 |
| Grant date | Mar 14, 1989 |
| Priority date | — |
| Expiry date | Dec 24, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H9/041
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An overcurrent protection system (10) for a power supply is disclosed. The system monitors the instantaneous flow of current between a power supply (12) and an electrical load (16) to detect when the flow of current exceeds a maximum rated amount. A counter (30) is used for counting the number of times that samples of the flow of current exceed the maximum rated amount synchronous with zero current crossing to generate a trip signal when a predetermined count is reached which disconnects the power supply (12) from the load. The counter (30) is decremented each time a predetermined time interval elapses in which the flow of current above the maximum rate is not detected as measured from a point of zero current flow between the power supply (12) and the electrical load (14). The invention may be used for both AC and DC power supplies.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.