Design and manufacturing of eddy current sensors

Heinrich Aschenbrenner

Eddy current displacement sensors measure distances, displacements, or positions of any electrically-conductive target. The eddy current principle is eminently suitable to applications in harsh industrial environments. Our standard program of eddy-current sensors is evenly balanced, with models starting from miniature sensors of 2 mm diameter up to comparatively large sensors with 140 mm diameter. The miniature sensors have the biggest value in production.

To obtain stable measurement values it is necessary to have a robust sensor. The coil is the main element of an eddy current sensor. Any variation of the coil and its housing will influence the measurement value. Robust design and a careful manufacturing of the sensor can help to eliminate such problems. There are two commonly used design principles: Coils on formers and formerless coils. It is very important at the development stages of a sensor that the correct choice of materials for the former and resin and made.

To obtain coils with consistent electrical parameters it is necessary to have a high level of winding precision. The sensor and coil respectively, should be caüaböe of maintaining its parameters throughout its lifetime. To facilitate this, good encapsulation and impregnation of the coil by using vacuum casting and vacuum impregnation are required.

This paper presents a brief overview of the design and manufacture of eddy current sensors.

<heinrich.aschenbrenner@micro-epsilon.de>

Heinrich Aschenbrenner

Entwicklung Sensorik

Micro-Epsilon-Messtechnik

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