Solid-state trip unit of an electrical circuit breaker with contact wear indicator
US4780786A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 24, 1987 |
| Grant date | Oct 25, 1988 |
| Priority date | — |
| Expiry date | Jul 24, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H1/0015
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A digital solid-state trip unit of an electrical circuit breaker is equipped with an electrical contact wear indicator enabling the degree of wear of these contacts to be known. Each time the circuit breaker performs a break, the microprocessor determines a contact wear value, in terms of the maximum value of the current broken. The correspondence between the wear value and the current broken is stored in a ROM memory and the successive wear values are added in a NOVRAM memory whose contents are representative of the degree of contact wear. These contents can be displayed to indicate to the user that the condition of the contacts has to be checked.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.