Magnetic shielding means for a current sensor of direct current switching apparatus
US5132497A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 26, 1991 |
| Grant date | Jul 21, 1992 |
| Priority date | — |
| Expiry date | Aug 26, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H71/125
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A Hall effect device is located in a focused gap of a flux concentrator disposed over one power terminal of a D.C. switching contactor to monitor flux induced by current flow. Magnetic fields from permanent magnets of the switching apparatus are shielded from the flux concentrator by a cup-shaped magnetic ring surrounding the concentrator, magnetically spaced therefrom, and a magnetic plate of the apparatus which is modified to accept more flux in a localized area of the sensor before saturation. The gap of the concentrator in which the Hall effect device is located is particularly positioned at a point where the magnetic field gradient from the permanent magnet field is minimum.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.