Contact status detector
US4977478A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 7, 1989 |
| Grant date | Dec 11, 1990 |
| Priority date | — |
| Expiry date | Apr 7, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H47/002
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
By providing two comparators, each of which have a reference voltage level source connected to one input, and separate voltage level producing/enhancing circuits connected to the contacts of a relay, so that each alternate switch configuration produces a different voltage level at the two comparators, a unique relay switch detection circuit is attained. Preferably, three separate voltage level producing/enhancing circuits are employed, with one circuit connected between the relay output and the two comparators, while the other two circuits are connected to the primary or the secondary relay contacts. Futhermore, the voltage level resulting from each particular switch configuration is pre-set relative to the reference voltage level source imputs to assure that the two comparators produce different combined outputs for each alternate switched condition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.