In electric motors, it is important to know that at a temperature of 40 ° C, the life of a continuously running ball bearing can be 3 to 4 years or more. However, for every 10 ° C of raising the working temperature its useful life decreases by an average of 50%. The correct lubrication of the bearings, in addition best generators here to allowing a better yield, avoids the rise of the temperature that damages the useful life of these equipments.
Lubrication of bearings is generally done with mineral grease. When operating temperatures are high (from 120 ° C to 150 ° C) or the rotational speeds are above 1,500 rpm, mineral oil is used for lubrication. These oils must have lubricating characteristics appropriate to the working conditions. On low power engines, initial lubrication in the assembly is provided to ensure a high number of operating hours. Sometimes the grease reserve will be sufficient for the entire life of the machine. On larger motors there is a need for external lubrication. The frequency of lubrication depends on the design of the bearings and the characteristics of the lubricants used.