Variable thermal and magnetic structure for a circuitbreaker trip unit
US5872495A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 10, 1997 |
| Grant date | Feb 16, 1999 |
| Priority date | — |
| Expiry date | Dec 10, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H2071/749
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A thermal and magnetic trip unit for a multi-pole circuit breaker includes a thermal structure having a bimetallic element and one or more heater elements. Each of the heater elements and a portion of the bimetallic element is generally "U" shaped defining a conductive path which extends from one leg of the U to the other leg. The heater elements and bimetallic element may be configured in parallel to reduce the level of current flowing through the bimetallic element and thus increase the current level at which the bimetallic element will trip the breaker. Alternatively, the heater elements may be configured in series with the bimetallic element, by inserting electrical insulators between the bimetallic element and each of the heater elements and connecting the various "U" shaped elements using a connecting bus which connects the second leg of one element to the first leg of the next element. In this configuration, the thermal structure defines a coil having one turns for each heater element and the bimetallic element. This coil may be used to implement a magnetic trip structure by inserting one or two magnetically permeable yokes, each yoke surrounding one leg of the combined ther…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.