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Arcing contact with protective sleeve

IP.com Disclosure Number: IPCOM000240181D
Publication Date: 2015-Jan-09
Document File: 6 page(s) / 159K

Publishing Venue

The IP.com Prior Art Database

Abstract

According to the present disclosure, an arcing contact (e.g. tulip) having a protective sleeve of electrically insulating material is provided. The arcing contact has a tube-like geometry with an inner wall, and the protective sleeve covers at least part of the inner wall. The protective sleeve is thus inserted inside the arcing contact (tulip) for preventing erosion of the tulip.

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Arcing contact with protective sleeve

TECHNICAL FIELD

The present disclosure in general relates to a tulip-type arcing contact for an electrical switch, for example load break switch or circuit breaker (CB), in particular for a high voltage circuit breaker (HVCB), the arcing contact having a protective sleeve. The present disclosure also relates to a CB, in particular a HVCB, having such an arcing contact.

BACKGROUND OF THE DISCLOSURE

High voltage circuit breakers (HVCB) have to fulfill severe criteria regarding electrical endurance, and need to be in a good condition even after several arcing events. One issue is erosion of the tulip contact. During an arcing event, hot plasma is created near the arcing contacts (plug and tulip), and the creation of this plasma may cause significant erosion of the arcing contacts. After several such arcing events, the erosion may cause reduction of contact material of the arcing contacts to such an extent that proper functioning of the HVCB can no longer been guaranteed. In extreme cases, parts of the tulip such as fingers may even disappear or detach, and such detached conductive pieces pose a dielectric risk.

Previous solutions included increasing the thickness of the tulip fingers, so that even if some erosion occurs, there would be enough material left. However, this would result in higher mass and also higher material cost.

The present disclosure aims at reducing the above-mentioned problems and at providing a HVCB having improved electrical endurance without the disadvantages of the previous solutions.

SUMMARY

According to the present disclosure, an arcing contact (e.g. tulip) having a protective sleeve of electrically insulating material is provided. The arcing contact has a tube-like geometry with an inner wall, and the protective sleeve covers at least part of the inner wall. The protective sleeve is thus inserted inside the arcing contact (tulip) for preventing erosion of the tulip.

Preferably, the protective sleeve is recessed with respect to a front portion of the arcing contact, such that a front face or tip face (i.e. opening face towards the other arcing contact, e.g. pin) is covered by a (conductive) front portion of the arcing contact. The protective sleeve particularly covers the portion of the tulip that has separate fingers separated by cuts extending in an axial direction towards the front side of the tulip.

The protective sleeve can be made from any non-conductive solid material (polymers, ceramic, or the like), but is preferably made of polytetrafluoroethylene (PTFE) or any other material having a sublimation characteristic (i.e. a material having a transition directly from the solid to the gas phase at the relevant operating conditions inside the CB).

The arcing contact is adapted for high or medium voltage applications. According to another aspect, a pair of arcing contacts is provided, a tulip as described above and a pin that is dimensioned for being inserted int...