Current-limiting circuit breaker having a selective solid state trip unit
US4644438A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 24, 1984 |
| Grant date | Feb 17, 1987 |
| Priority date | — |
| Expiry date | May 24, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H2071/1036
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electric current-limiting circuit breaker comprises a pair of separable contacts and a selective solid state trip unit including an actuator cooperating with a latch mechanism for actuating the contacts to a positive open position upon occurrence of an overcurrent condition. The movable contact may also be moved by electrodynamic repulsion towards the open position when the fault current exceeds a predetermined threshold to effect current limiting. A tripping control device has an electronic counter which counts successive opening and closing cycles of the contacts so as to trip mechanism after a given number of cycles. The trip unit further comprises a first time delay tripping circuit, and a second instantaneous tripping circuit which cooperates with the cycle counter so as to ensure either instantaneous tripping or tripping by counting up to a number of cycles preselected on a setting selector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.