Electromagnetic trip device with tripping threshold adjustment
US4939492A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 18, 1989 |
| Grant date | Jul 3, 1990 |
| Priority date | — |
| Expiry date | Jan 18, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H71/2463
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The tripping adjustment range of a magnetic trip device with a plunger core is increased by providing, in the movable plunger core, a groove whose edges define polar surfaces bounding air-gaps with the edges of the yoke in such a way as to generate in the minimum adjustment position a force which is added to the attractive force of the movable core by the stationary core, and inversely a force in the maximum adjustment position which is subtracted from the attractive force of movable plunger core. The trip device excitation coil is offset with respect to the yoke to increase the adjustment range, and a return device with adjustable stop and decreasing return force as the movable core approaches the stationary core, contributes to increasing this tripping threshold adjustment range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.