Experimental investigation of factors affecting the electrical performance of the stub to carbon connection

Abstract

A facility has been built and commissioned to enable research into improving the electrical energy efficiency (and reducing associated greenhouse gas emissions) of very large metal-metal and metal-carbon electrical connections used by energy intensive metal-winning processes (aluminium, copper, zinc, ferro-alloys). The facility is able to test large-scale and full-scale industrial electrical connections up to 1000 kg, at up to 5000 A DC and 1200 °C in an inert atmosphere. This paper presents the first results of an experimental investigation using the facility to study the main influencing factors affecting the electrical contact resistance for the stub to carbon connection, which is one of the major electrical connection resistances found in aluminium smelting plants. The investigation clearly shows increasing electrical contact resistance for; (i) decreasing stub diameter, (ii) increasing gap under stub and (iii) stub eccentrically positioned in the stub hole.