What is the major failure mode for electric motors?

The major failure mode for electric motors is indeed often linked to over greasing. When bearings are lubricated, it is critical to apply the right amount of grease. Over greasing can lead to several issues, such as excessive heat generation, which can degrade the lubricant more rapidly and lead to a dry condition, countering the efforts made to maintain adequate lubrication. Additionally, too much grease can produce pressure that forces grease out of the bearing, allowing for contamination from dirt or water, and disrupting the lubrication effectiveness.

In contrast, while dirt and water are also harmful to the operation of electric motors, they are typically the result of other failures, such as inadequate sealing or environmental conditions rather than a direct cause of motor failure linked to the lubrication itself. Under greasing, while it can lead to increased wear and heat, it is not depicted as the major failure mode when considering the frequency and severity of issues caused by over greasing in applications involving electric motors. Therefore, understanding the nuances of lubrication practices and their impacts on motor performance affirms why over greasing stands out as a significant concern in maintaining electric motor health.