Method and system for monitoring the condition of a plurality of electrical devices
US4918390A · kind A · utility
Inventors
Key dates
| Filing date | Apr 13, 1989 |
| Grant date | Apr 17, 1990 |
| Priority date | — |
| Expiry date | Apr 13, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/50
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and system for monitoring the condition of a plurality of electrical devices, particularly electrical switches actuated by sensors, to determine the condition of each and the location of e.g., a malfunctioning device. The electrical devices are connected in parallel across a pair of line conductors. A voltage-dropping element is inserted in series with the line at the input side of each device, and a current-limiting element, passing a fixed current independently of voltage above a predetermined threshold, is inserted in series with the respective device. Initially, a voltage is applied to the line of greater magnitude than the sum of the predetermined threshold and the voltage of the first device, and is sequentially increased in a plurality of steps, while the current passing through the line initially and after each of the voltage steps is measured.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.