The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 05, 2000
Filed:
Jan. 07, 1999
Joachim Glatz-Reichenbach, Baden-Dattwil, CH;
Ralf Strumpler, Gebenstorf, CH;
Jorgen Skindhoj, Frederiksberg, DK;
Felix Greuter, Baden-Rutihof, CH;
ABB Research Ltd., Zurich, CH;
Abstract
The resistor body of a nonlinear resistor element having PTC characteristics includes a pulverulent first filler, whose material, e.g. TiB.sub.2, TiC, VC, WC, ZrBr.sub.2, MoSi.sub.2, has a specific conductivity of at most 10.sup.-3 .OMEGA.cm and in which the particle sizes are between 10 and 40.mu., and also, in order to improve the voltage sustaining capability by extending the switching zone and to achieve uniform energy absorption, includes a likewise pulverulent second filler having varistor characteristics and particle sizes between 50 and 200.mu., whose specific resistance at field strengths .gtoreq.2000 V/cm such as occur in the switching region of the resistor element and above, is at most 50 .OMEGA.cm, preferably at most 15 .OMEGA.cm, the fillers being embedded in a matrix made of a thermoplastic, in particular HD polyethylene or a thermoset. The average particle size of the second filler should exceed that of the first filler by a factor of from 2 to 5. A potentially particularly suitable material for the second filler is SiC doped with Al, B, Ga, In, N, P, As, as is similarly doped ZnO.