Residual current devices
US10581234B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 20, 2017 |
| Grant date | Mar 3, 2020 |
| Priority date | — |
| Expiry date | Mar 15, 2038 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/334
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A residual current device (RCD) comprises test circuitry which issues intermittent first test pulses each simulating a residual current fault for which a corresponding fault signal is generated. In the case of a fault in which a corresponding fault signal is not received in respect of a first pulse, the RCD attempts to force the load contacts open. The test circuitry further issues intermittent second test pulses at a frequency less than that of the first test pulses, each second test pulse simulating a residual current for which a corresponding fault signal is generated. The duration of each corresponding fault signal is greater than the response time of the load contacts to allow the load contacts to open. If the test circuitry detects that the load contacts do not open, the RCD attempts to force the load contacts open.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.