Circuit breaker with adjustable low magnetic trip
US4983939A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 5, 1989 |
| Grant date | Jan 8, 1991 |
| Priority date | — |
| Expiry date | Oct 5, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H71/7463
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A circuit breaker has a magnetic trip assembly which can be adjusted to trip the breaker for low level overcurrents in the range of five to ten times rated current. The magnet trip includes for each pole of the breaker a helical torsion spring having one torsion arm which biases an armature against an adjusting bar to form a gap between the armature and a stationary magnetic structure in which magnetic flux strong enough to attract the armature and trip the breaker is induced by overcurrent. A second torsion arm of the spring has a first portion which bears against and slides along a pivot member carried by the adjusting bar to adjust the bias force applied to the armature by a given amount per unit travel of the adjusting bar over a low trip current portion of the range of travel of the adjusting bar. A second terminal portion of the second torsion arm of the spring extending at an angle from the first portion engages and slides along the pivot member on the adjusting bar to provide a greater change of bias force per unit travel of the adjusting bar at the higher trip current settings. Movement of the adjusting bar adjusts the spring bias for all poles of a multiphase circuit brea…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.