The coatings apply to the outside or inside

Update:17-05-2018

Water and humidity are enemies of all bearing lubricants. Heat from running motors tends to evaporate moisture, but condensation can build up when motors are powered down. Condensation is impossible to prevent, but its harmful effects can be negated by the use of lubricants fortified with rust inhibitors. Users should frequently rotate shafts of idle motors whenever condensation is suspected. Good seals can help keep humidity out of the bearings as well. And avoid direct water spray on seals during wash downs.
One fix for electric arcing is specialized ceramic coatings. The coatings apply to the outside or inside diameter of a bearing to electrically insulate it from the shaft. The use of hybrid bearings is another way to stop arcing. Such bearings substitute ceramic balls or rollers for metal rolling elements to effectively insulate bearings from the inside.

A less-obvious problem affecting household appliances bearing is electric arcing. Electric arcing tends to be an isolated and localized event, similar to a series of small lightning strikes that melt and retemper internal bearing surfaces. The result: some surface material flakes away and spalls out, leaving behind microcraters. Characteristic "fluting" patterns on bearing surfaces indicate damage from electric arcing. Fluting is caused by rolling elements touching the microcraters and etching a pattern into the races over time. This and wear debris raise bearing noise and vibration, leading to deterioration of contact surfaces and eventual bearing failure. Arcing may not always directly hurt bearings but instead damages the lubricant. Highly localized temperatures associated with arcing char or burn the oil and break down additives.

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