Magnetic Sensors in High Magnetic Field Evironments

Maybe the benefits of using magnetic encoders over optical encoders have captured your attention. They have greater durability and reliability, an ability to withstand harsh environments, higher vibration and shock tolerance, withstand higher temperatures, come with much larger gap tolerances and come in compact packaging.

But motors and many industrial environments have high magnetic fields. What happens to a magnetic encoder when it is used in a high magnetic field?  Are any of the advantages or its performance compromised?

Most magnetic sensing technology is differential. The sensor detects the difference between the magnetic north and south poles. Stray (common mode) magnetic fields are cancelled. At Timken, we’ve tested the quadrature signals to more than 800 gauss common mode field.

Some magnetic encoders do appear to handle stray fields better. Look at the chart below for a comparison of some of the leading magnetic sensors/encoders on the market that we have tested. Only two of them show no effect from the stray magnetic fields – see the green and blue lines. (The Timken encoder is the blue line at the bottom). In fact, Timken sensing technology is successfully buried inside motors on a regular basis where there are large magnetic fields.

Magnetic encoders have a number of advantages and stray magnetic fields won’t compromise the performance if you’ve chosen the right one.

Magnetic encoders from Timken offer the highest accuracy and are resilient in the most challenging environments, including those with high magnetic fields. Questions? Reach me at 603.358.4760 or send me at email at