Computer-checking of the position of a switch whose contacts where oxidized
US5258654A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 1992 |
| Grant date | Nov 2, 1993 |
| Priority date | — |
| Expiry date | Mar 30, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H1/605
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A precharged capacitor connected in parallel with the contacts of an open switch discharges through the switch upon closure. Oxides on the switch contacts are broken through upon closure of the switch to produce a good electrical connection. The capacitor provides sufficient voltage and transient current to clean the switch contacts. A microprocessor having signals of only 5 volts can interrogate a plurality of such switches by multiplexing some semiconductor switching circuits that energize the interrogated switches and by synchronously multiplexing some microprocessor input circuits. The microprocessor's input circuits therefore receive signals indicating the status of each switch in turn.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.