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.
Let’s look at what is needed to accomplish this.
• Magneto-resistive sensors allow for a bearing free encoder design. The magneto-resistive sensor on an Avtron Encoder does not depend on an exact alignment to read the magnetic poles on the rotor. This allows a large air gap and movement of the rotor on the shaft where it is mounted. You can utilize motor bearings or existing machine/line shaft bearings to keep the rotor shaft stable enough to mount the rotor while you mount the sensor housing to a motor/machine flange.
• Potted electronics allow for a seal free encoder design. With no precision optical gratings, LEDs or photocells, Nidec-Avtron is able to completely pot our electronics, including the sensor, making them impervious to liquid/moisture and dust. No seal is required to protect the internal electronics.
Manufactured without seals and bearings, the modular encoders available from Nidec-Avtron eliminate ninety eight percent of mill encoder failures.