Overcurrent trip circuit
US5181155A · kind A · utility
Inventors
Key dates
| Filing date | Aug 30, 1990 |
| Grant date | Jan 19, 1993 |
| Priority date | — |
| Expiry date | Aug 30, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/08
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An overcurrent trip circuit monitors the rate of rise of the current and the magnitude of the current in a power conductor and opens a circuit containing the power conductor when either the rate of rise of the current exceeds a first preselected limit value or the magnitude of the current exceeds a second preselected limit value. The inherent inductance in a metering shunt is used to produce a voltage signal that contains a component which is representative of the rate of change of current in a power conductor. This voltage signal is compared to a first reference signal to produce a trip signal when the voltage exceeds the first reference signal. In addition, the voltage signal is processed and the processed voltage signal is compared to a second reference signal to produce a second trip signal when the magnitude of the processed voltage signal exceeds the magnitude of the second reference signal. The power circuit is then opened in response to either of the first or second trip signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.