Through-Transmission Impedance Measurements on Moving Metallic Sheets

Thumbnail Image
Date
1992
Authors
Kahn, Arnold
Mester, Michael
Major Professor
Advisor
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Research Projects
Journal Issue
Department
Abstract

Eddy current measurement of electrical resistivity provides a method of sensing temperature during metals processing, thus offering a method of feedback control [1,2]. This method assumes a known resistivity-temperature relation for the alloy being processed. However, in many common processing configurations a measurement of the impedance of the coil system can depend on the velocity of the product being tested. In the through-transmission (abbreviated thru-trans) configuration for monitoring moving metallic sheets, the component of the exciting magnetic field normal to the sheet induces an electric field in the sheet transverse to the direction of the velocity. This modifies the induced current distribution and thus changes the shielding of the field at the receiver coil relative to the condition for the static case. This effect is significant even in the case of extruded aluminum moving at 150 ft/min. In high speed rolling, at 1000 ft/min or greater, the effect of velocity is even more significant.

Comments
Description
Keywords
Citation
DOI
Copyright
Wed Jan 01 00:00:00 UTC 1992