How often should a sealed ball bearing in an electrical motor be lubricated?

Sealed ball bearings in electric motors are designed to be maintenance-free for their operational lifespan. They come pre-filled with a specific type of lubricant that is sealed inside the bearing, protecting it from contaminants and ensuring that it operates smoothly without the need for regular lubrication. This self-contained system minimizes the risk of over-lubrication or contamination, which can occur if additional grease or oil is introduced. Because of this design, the ideal practice is to leave sealed bearings as they are, without trying to lubricate them further.

In contrast, options that suggest regular lubrication or addressing lubrication based on noise ignore the foundational design of sealed bearings. These bearings are built to maintain their lubrication without outside interference, meaning that added lubrication, when unnecessary, can be counterproductive. Thus, choosing the option of "never" lubricating highlights an understanding of modern bearing technology and proper maintenance protocols for sealed ball bearings.