RF (Eddy Current) Speed Sensors

RF speed sensors offer low speed response, no drag, large air gaps and sensing characteristics which enable this type of speed sensor to sense non-ferrous metals like aluminum or nonmagnetic stainless steel in addition to ferrous metal. Unlike their VR counterparts, an RF speed sensor is not a passive device and requires coupling with a signal conditioners/preamplifier. These devices produce a digital square wave output versus the analog sine wave of the VR speed sensor.

Custom RF Speed Sensors

In addition to our standard models, RF speed sensors are available in custom lengths, diameters, configurations, and mounting threads. Custom operating specifications (output options, etc.) are available, as well as options such as pigtail leads or NPT threading. See additional sensor customization options.

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Principles of Operation – RF (Eddy Current) Speed Sensors

Advantages of Motion Sensors RF sensors are: near zero speed response, no magnetic drag, large air gaps, and the ability to sense non-ferrous metals like aluminum and nonmagnetic stainless steel, as well as ferrous metals. RF sensors use a modulated carrier signal to sense rotating metals. Unlike their Variable Reluctance (VR) counterparts, RF sensors require an internal or external preamplifier/signal conditioner to operate. When a target is sensed, eddy currents are formed which decrease the signal amplitude. The preamplifier/signal conditioner demodulates the signal, detects the voltage drop-offs, and produces a square pulse wave (digital) output with a frequency directly proportional to the number of turbine blades, gear teeth, etc. that have been sensed.