Bearings and seals are the main failure items for any encoder in a mill environment today. Lip seals, shaft seals and bearings all have static surfaces in contact with rotating surfaces. Gradually these seal points will wear or break down and allow material to pass into the encoder housing and contaminate optics and short electronics. As bearing surfaces wear, radial movement increases at both seal surfaces, accelerating failure and causing optical path misalignment. Eliminating the bearings and seals from your encoder applications will drastically lengthen the life of your feedback devices.