Variable Reluctance Speed Sensors

What are variable reluctance sensors?

Variable reluctance speed sensors measure the position and speed of moving ferrous objects. Their versatility, simplistic design, and relatively low cost of manufacturability make them attractive for use in the aerospace industries. The variable reluctance sensor consists of a permanent magnet and a ferromagnetic pole piece surrounded by a coil of wire. The sensor generates an analog voltage output signal when a ferromagnetic material passes by the tip of the pole piece. The magnitude of the induced voltage is therefore a direct function of the flux linkage in the coil as a function of time. The voltage signal is sent to the control unit where it is often converted to a digital signal to support the controlling function.

The benefits of VR sensors

VR sensors consist of many benefits such as low cost and robust proven speed sensing technology. They require few wiring connections and are highly reliable. They have self-generating electrical signals thus requiring no external power supply. One area that the VR sensors excel in is the ability to operate in high-temperature applications, making them a good fit for sensing the turbine speed of a jet engine. The sensors are highly customizable and can meet specific applicational requirements.

What you will find in this white paper

Download this white paper and learn about the electrical and electromagnetic models developed and utilized at HarcoSemco.  The paper walks you through the study carried out to formulate a universal model that is capable of predicting the dynamic performance of speed sensors.