Title :
Analysis of the Lift-off Effect of Phase Spectra for Eddy Current Sensors
Author :
Yin, W. ; Binns, R. ; Dickinson, S.J. ; Davis, C. ; Peyton, A.J.
Author_Institution :
Dept. of Eng., Lancaster Univ.
Abstract :
This paper presents an analytical model which describes the inductance change when a double air-cored coil sensor is placed next to a conducting plate. Analysis of the analytical model reveals that the phase signature of such sensor is virtually lift-off independent. This finding is verified by numerical evaluations. This paper also finds that the phase signature of a ferrite U-cored sensor can be approximated by that of a double air-cored sensor of similar size, and therefore possesses similar lift-off independent property. Measurements made with a sample U-cored sensor next to plates of non-magnetic and magnetic materials verified the theoretical results
Keywords :
approximation theory; coils; eddy currents; magnetic cores; magnetic materials; magnetic variables measurement; spectral analysis; U-cored sensor; air-cored coil sensor; analytical model; conducting plate; eddy current sensors; inductance change; lift-off effect; magnetic materials; nonmagnetic materials; phase signature; phase spectra; Analytical models; Coils; Current measurement; Eddy currents; Ferrites; Inductance; Magnetic materials; Magnetic sensors; Sensor phenomena and characterization; Testing;
Conference_Titel :
Instrumentation and Measurement Technology Conference, 2005. IMTC 2005. Proceedings of the IEEE
Conference_Location :
Ottawa, Ont.
Print_ISBN :
0-7803-8879-8
DOI :
10.1109/IMTC.2005.1604477
