Earth-leakage circuit breaker with automatic monitoring capability
US5956218A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 6, 1997 |
| Grant date | Sep 21, 1999 |
| Priority date | — |
| Expiry date | May 6, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/05
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An earth-leakage circuit breaker has a totalizing current transformer, a magnetic trip device and switchgear with main current contacts for the main leads. A current-signal generator, a current sensor, a time-signal generator and an electronic timer wherein the switching value and response time of the circuit breaker are measured at predetermined intervals, compared with reference switching values and response times and, if these reference values are exceeded, an alarm is promptly given. During the measurement, a locking device prevents the main current contacts from opening and/or when predetermined limiting switching and response times are exceeded, the locking device opens the main current contacts and subsequently acts as a lock preventing the contacts from closing again, which is equivalent to fail-safe behavior. In addition, the switching value of the circuit breaker is multiplied by its response time and the product, which may exceed a particular constant value, is used for monitoring purposes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.