Electrical apparatus for differential protection with a test circuit
US5978191A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 1997 |
| Grant date | Nov 2, 1999 |
| Priority date | — |
| Expiry date | Sep 11, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/335
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A trip device comprising a differential current detection transformer, a trip relay of a breaking mechanism of the circuit breaker and a test circuit for checking the operation of the trip device. The relay comprises a fixed yoke bearing a coil and a blade that is mobile with respect to the yoke. During normal operation of the trip device, the blade is held magnetically in the position pressing against the yoke and when a differential current occurs, the blade actuates the breaking mechanism. The test circuit generates a vibration of the blade, without causing tripping of the mechanism, in order to check its ability to disengage from the fixed yoke. Advantageously, this vibration is obtained by application of a voltage in the form of pulses to the terminals of the coil.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.