If operating temperatures are significantly high or, if rotation speeds exceed 1,500 rpm, it is necessary to use mineral oil to lubricate. The oils must have lubricating properties that are appropriate to the working conditions. In the case of small power engines, the initial lubrication in the assembly is provided in order to ensure a high number of operating hours. Grease reserve may be sufficient for the entire life of the equipment. On larger motors there is a need for more lubrication. The periodicity of lubrication varies according to the design of the bearings, as well as the properties of the lubricants used.
In this way, it is important to know that at a temperature of approximately 40 ° C, the life of a continuously running ball bearing can be on average from 3 to 4 years or even longer, depending on the conditions. Therefore, for every 10 ° C to raise the working temperature, the durability can automatically decrease. In addition to providing better performance, lubricating the bearings can prevent the temperature rise that can affect the life of these devices. Normally, lubrication of the bearings is carried out with mineral grease. https://www.mrosupply.com/ac-motors/single-phase-motors/26616_cl1304_baldor/