This paper describes several electromagnetic sensing arrangements for measuring the percentage of austenite, which has transformed into ferrite in hot rolled steel as it cools. The results from laboratory experiments are presented. These indicate that all the sensors produce outputs, which are associated with the percentage transformation. Using the knowledge gained from this work it is proposed to build an on-line trial sensor for use in a hot strip mill.

Using electromagnetic methods to monitor the transformation of steel samples

Position sensing in nuclear remote operation

Al need has arisen in research on micro machines for mi cro position sensors which are less affected by scaling laws than existing capacitive sensors. This paper de- scribes the development and operation of a non-contact inductive position sensor for use in micro magnetic bearings. As the sensor footprint area, in the micro machines being considered, will be less than I mm square the sensor coil inductances and impedance levels are small, and the parasitic and demodulator input capacitances begin to have a major influence on the transducer op- eration. To minimize the loading effect of these capac itances wideband current to voltage (I-V) converters have been introduced to match the output of the sen sor coils to the input of the signal conditioner circuit. Test results for these I-V converters are presented. Also overall test results of the position transducers showing transducer linearity and sensitivity for a range of sensor coils are presented.

A Non-contact Inductive Position Sensor For Use In Micro Machines

The authors present experimental results concerning inductance variation of 'C'-type magnetic circuits for proximity sensors, as a function of different parameters: position and geometry of coils, magnetic circuit material, thickness of target, frequency of measuring signal, thermal hysteresis of magnetic circuits and some auxiliary construction elements (protective box, coating resins).

Study of variable inductance transducers as proximity sensors: II. Experimental study using 'C'-type magnetic circuits

In this paper we investigate trans-impedance amplifiers which can be used to minimize the influence of stray capacitances on the operation of signal conditioners used for instrumentation applications such as inductive microsensors for micromachines. The effect of stray capacitances can be minimized when using this type of amplifier by ensuring that its input impedance is small. A technique for realizing very low input impedances over a wide bandwidth for these amplifiers is studied both analytically and experimentally for transistors having a wide range of gain - bandwidth products . In addition an improved circuit configuration which further reduces the amplifier's input impedance at high frequencies is investigated by computer simulation.

https://iopscience.iop.org/article/10.1088/0957-0233/8/11/022/pdf

Wide-band low-input-impedance trans-impedance amplifiers for instrumentation applications

The authors are concerned with the computer-aided study of magnetic circuit/coil/target systems for proximity inductive sensors: for this study software for computation of magnetic parameters is used. A specific method for using the software and the results obtained by applying this method to four typical geometries of magnetic circuits are presented. The parameters studied are: the geometry of the magnetic circuit, the geometry and position of the coils, the permeability mu of the magnetic circuits and targets and the saturation of the magnetic circuits.

http://iopscience.iop.org/article/10.1088/0957-0233/1/10/007/pdf

C Poupot

Papers

Study of variable inductance transducers as proximity sensors: I. Computer-assisted study