Residual current devices
US7468871B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 10, 2003 |
| Grant date | Dec 23, 2008 |
| Priority date | — |
| Expiry date | Oct 20, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R19/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A residual current device (RCD) protects a circuit by tripping in response to an imbalance signal representative of residual current imbalance in the circuit. The RCD trips the circuit when the imbalance signal exceeds a predetermined threshold rating. The RCD includes a sense coil for generating the imbalance signal and a test coil for introducing a simulation residual current imbalance into the device so as to increase the imbalance signal. A processor monitors the imbalance signal and determines the simulation residual current imbalance required to increase the imbalance signal to a level that corresponds to the predetermined threshold rating so that the sense coil senses the sum of any residual current imbalance in the circuit being protected and the simulation residual current imbalance in order to test operation of the RCD against the predetermined threshold rating.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.