Abb Schweiz Ag

Abb Research Ltd.

Abb Technology Ag

Ragnar Österlund

Felix Greuter

Michael Hagemeister

Reto Kessler

Åke Öberg

Henrik Hillborg

Erik Jonsson

Leif A Pettersson

Oliver Beck

Peter Hidman

The present invention relates to a varistor material for a surge arrester with target switching field strength ranging from 250 to 400 V/mm comprising ZnO forming a ZnO phase and Bi expressed as BiOforming an intergranular bismuth oxide phase, said varistor material further comprising a spinel phase, characterized in that the amount of a pyrochlore phase comprised in the varistor material is such, that the ratio of the pyrochlore phase to the spinel phase is less than 0.15:1.

High field strength varistor material

A varistor including a varistor body with two parallel end faces made of a material that contains one or more metal oxides, and at least one electrode made of an electrically conductive electrode material arranged on any of the end faces of the varistor body. The electrode includes a layer of electrode material coated on the end face by means of an ion- or atom-transferring method, whereby the layer has a thickness within the interval of from 5 micrometers to 30 micro-meters.

Method of manufacturing a varistor

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Ludvika, Sweden

Ragnar Österlund