Use solvent-free paints whenever possible.
If possible, choose impregnation varnishes that do not contain oxidizing components, such as epoxy-urethane or unmodified epoxy-based impregnation varnishes.
When using melamine alkyd impregnation varnish, the curing temperature and time should be adjusted. A curing temperature slightly above 130°C (e.g., 135°C) and a curing time greater than 180 minutes are recommended. The process must be strictly followed, especially during hot and humid seasons, because from a rust prevention perspective, the drying (curing) time specified in the paint manufacturer's specifications may not be sufficient, given the specific internal geometry of the motor.
Use paints that do not contain volatile acids.
Select paints with good hydrolysis resistance.
Use mineral oil-based bearing grease whenever possible.
When the motor manufacturer injects grease, to prevent water vapor and dust from entering the bearing and causing noise and potential corrosion, the grease container should be sealed, even during the greasing process. The amount of grease injected should be consistent with the standard; for example, for a 6202 bearing, the reference value is in the range of 0.60 to 0.80g. The greasing process should be kept clean and dry.
Use plastic film packaging with micropores to allow some breathability before the motor is put into operation. When using sealed plastic film packaging, paint fumes will remain inside the bearing, and moisture will condense, which should be avoided.
The grease may deteriorate under the high temperature during the curing of the powder coating or paint on the motor cover.
Consult with the bearing manufacturer to use more effective rust inhibitors during bearing production.
To completely solve the problem of paint-induced rust, the motor manufacturer, bearing manufacturer, and paint manufacturer should collaborate to combine their expertise and address the bearing corrosion issue.
