Lion Precision Publishes Electrical Runout Study from Professional Instruments

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A new study documents the magnitude of electrical runout errors which occur when eddy-current displacement sensors are used with targets which move in another axis.

A new TechNote from Lion Precision features a study of electrical runout from Professional Instruments. Electrical runout is a phenomenon that causes eddy-current sensors to generate errant displacement signals when monitoring targets that move in an axis other than the measured displacement axis. This usually applies to rotating targets. Ferrous materials are especially susceptible to electrical runout. A new study from Professional Instruments details and quantifies this error’s relationship to material types. The study was performed with aluminum, titanium and carbon steel. The steel generated the largest error with a magnitude of 5.9 micrometers.

“For many users of eddy-current displacement sensors, a six micron error is within the tolerance of their measurement,” according to Mark Kretschmar, Lion Precision communication manager. He adds, “But the typical Lion Precision customer is looking for submicron precision in their measurements and this becomes a significant factor.” The errors for aluminum and titanium were less than one micrometer. The TechNote is intended to help designers, engineers and metrologists understand the relationship between their measurement’s needed precision and the capabilities of eddy-current sensor technology.

The TechNote explains the underlying principles of eddy-current sensors and why electrical runout is created in moving or rotating targets. When high precision is required, capacitive displacement sensors are a better choice as they do not exhibit electrical runout effects. But some measurements must be made in dirty or hostile environments to which eddy-current displacement sensors are better suited.

The TechNote can be found here:

The Technical Library on the Lion Precision website ( has dozens of other documents detailing the operation, application and use of noncontact displacement sensors. It is the company’s goal to be the leading provider of technical information to empower users to understand how to best make a precise measurement.

In 1958, Lion Precision was the first company to provide capacitive noncontact displacement sensors to industry. The company has expanded its product offering to include eddy-current displacement sensors and some application specific sensors for the machine tool, packaging and PCB industries. Lion Precision is focused on assisting users in sensor implementation by providing technical knowledge resources, expert guidance and optimized systems including custom designs.

For more information, contact Lion Precision:
Lion Precision
563 Shoreview Park Road
St. Paul, MN 55126 USA

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Mark Kretschmar
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