Reliability Evaluation of a Wiegand Effect Wheel Speed Sensor

A wheel speed sensor for use in automotive applications is analyzed based on the Wiegand effect. A literature search was conducted concurrently with our testing, and it was found that while there exists several papers dealing with an explanation of the effect and notes on possible applications, there was virtually no data available on long-term environmental and electrical testing of sensors utilizing the effect. A program was undertaken to perform this testing. Computer modeling of the sensor was also performed to aid in system simulation. Testing was performed according to SAE J1211 and JEDEC Standard No. 22 and in a road going vehicle instrumented to monitor the sensor. Data will be shown to demonstrate the reliability of the Wiegand sensor in the automotive environment and its low sensitivity to mounting location accuracy. One drawback which will be discussed is a large aperture which contributes in part to the low mounting sensitivity.