Magnetic flux shifting ground fault trip indicator
US4157520A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 4, 1975 |
| Grant date | Jun 5, 1979 |
| Priority date | — |
| Expiry date | Nov 4, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H71/322
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A low energy mechanically driven and electromagnetically actuated ground fault trip indicator is taught. The ground fault trip indicator utilizes the magnetic flux of a permanent magnet in a first flux path to maintain a movable armature biased against a spring. An electromagnet is disposed to provide magnetic flux in opposition to the magnetic flux of the permanent magnet. The electromagnet is not energized for providing the opposing flux until a pulse is received from an appropriate ground fault trip detecting circuit. When the appropriate pulse of energy is applied to the electromagnet, a portion of the flux of the permanent magnet is cancelled allowing the spring to force the armature into a new position. In this position the flux of the permanent magnet is reestablished in a second flux path. When the indicator is in the latter position indication of the occurrence of a ground fault is given.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.