Magnetic Shielding of Linear Variable Differential Transformer with Pure Iron Foils

Abstract

Accuracy of Linear Variable Differential Transformer (LVDT) is influenced due to presence of an external magnetic field. In this paper an experimental study is presented which uses a pure iron foil for magnetic shielding of the sensor. The pure iron used in the present study is manufactured with a novel method of electrodeposition, cold rolling and intermediate annealing in a controlled environment. The magnetic properties of the pure iron manufactured with the new method are characterized by Vibrating Sample Magnetometer (VSM) to determine initial magnetization and hysteresis curve. The pure iron material exhibits properties, which make it a suitable candidate material for magnetic shielding. Further, the pure iron foils are used for electromagnetic shielding of LVDT to ensure that incorporation of the shielding ensures reduction in the sensor error from 7.7% to 2.3% and minimizes the effect of an external magnetic field on the sensor performance.