Single-phase fault detecting circuit breaker
US4279007A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 12, 1979 |
| Grant date | Jul 14, 1981 |
| Priority date | — |
| Expiry date | Jul 12, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/34
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electronic control system and associated circuit breaker is taught in which the effect of in-rush current on mining equipment, for example, in regard to tripping is minimized even though a single phase fault of an equal magnitude is adequately provided for. This is done even though the same circuit breaker system and circuit breaker for both situations is utilized. A resistive capacitive series network is utilized to separate the ripple frequency from the DC value of the overload current being sensed. If the ripple component is relatively high for a given amount of overload current in the lines to be protected, then that is indicative of a single-phase fault for which circuit breaker tripping should be provided. If on the other hand the same amount of current causes a ripple component of a relatively low value, that is indicative of balanced three-phased overload which is usually indicative of in-rush or spurious transients. In any case, higher values of overload will cause other portions of the circuit to trip for safety. A time delay is provided at the output of an operational amplifier interconnected with the series resistive capacitive circuit. The time delay provides furthe…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.