Variable high-current resistor, especially for use as protective element in power switching applications & circuit making use of high-current resistor

US5644283A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Hubert Grosse-Wilde · Neunkirchen, DE
• Jorg Kieser · Albstadt, DE
• Wilfried Jaehner · Wendelstein, DE
• Fritz Pohl · Hemhofen, DE
• Reinhard Steger · Glückstadt, DE
• Gert Vogel · Amberg, DE

Key dates

• Filing date: Feb 14, 1995
• Grant date: Jul 1, 1997
• Expiry date: Feb 14, 2015

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01C10/10
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

A variable high-current resistor, especially for use as a protective element in power switching technology has already been proposed, which contains carbon as a resistance material, at least one boundary layer with a transition zone to another electric conductor being provided. By applying a contact pressure, the resistance in the transition zone can be kept low. Under the prior art, the resistance is converted into a highly resistive state by means of Joulean heat. In accordance with the invention, the contact pressure of the variable high-current resistor is able to be selectively influenced, the carbon- and/or carbon-black-containing layer being pressed by the surface pressure with a preset first value against the other conductor to adjust the low-resistance state of the resistor, and that, in the event of a short-circuit, this contact pressure being able to be reduced in a short enough time to a second value, at which the resistance in the transition zone goes up by at least two orders of magnitude. High-current resistors of this type are able to be used in conjunction with circuit-breakers, power semiconductors, contactors and vacuum contactors.