What is the primary difference between non-contact and contact seals in bearings?

The primary difference between non-contact and contact seals in bearings lies in the way they interact with the moving parts of the bearing, resulting in varying levels of friction. Non-contact seals are designed to maintain a separation from the rotating shaft or housing, which minimizes friction. This characteristic allows for smoother operation and reduces wear on both the seal and the shaft. The design of non-contact seals facilitates the free movement of the rotating parts without the added resistance generated by direct contact.

In contrast, contact seals engage with the rotating surfaces. While they can provide excellent sealing capabilities to prevent the ingress of contaminants, they typically generate more friction due to the contact. This can lead to increased wear and heat generation over time.

Therefore, the correct answer illustrates that non-contact seals are advantageous for allowing minimal friction, contributing to the overall efficiency and longevity of the bearing system.