The quality of grease has such an impact on bearing temperature rise
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The unit uses the most common calcium-based lubricant; the temperature of the bearing at the upper end of the submersible pump remains stable at 75°C. This indicates that the temperature rise is not within acceptable limits. After thorough investigation, no cause was found, and it was not possible to replace the lubricant with a lithium-based one. As a result, the temperature stayed stable at 45°C. It’s frustrating – regardless of the amount of lubricant used, it was not expected that the quality of the lubricant would have such a significant impact on temperature. It seems that lithium-based lubricants are significantly better than calcium-based ones
Operating temperature: Calcium-based greases can be used between -10 degrees and 80 degrees, while lithium-based greases can be used between -20 degrees and 120 degrees. Since your values fall within these ranges, the only possibilities to consider are whether it is still the bearing running-in period, or whether too much calcium-based grease has been used. I really can’t think of any other problems
I think it will have an impact; the performance of calcium-based materials is inferior, and this is also related to the condition of the equipment
Calcium-based greases have good water resistance, are not prone to emulsification, exhibit strong adhesion to metal surfaces, and also have good colloidal stability; they do not tend to release oil during storage. However, the biggest drawback of calcium-based greases is their low dropping point, which is usually around 90 degrees； Water acts as a structural stabilizer for calcium-based greases. When the operating temperature exceeds 100 degrees, water evaporates, which leads to the disruption of the structure of the calcium-based grease and results in a loss of its lubricating properties. Therefore, calcium-based greases are generally used in areas where the operating temperature does not exceed 60 degrees; they can also be used in areas that are prone to moisture or contact with water. Lithium-based greases possess a variety of excellent properties; their main advantage over calcium-based greases is their high dropping point, which can reach 180 degrees, allowing them to be used in environments with temperatures up to 120 degrees for extended periods. It has good mechanical stability, colloidal stability, chemical stability, and low-temperature performance; its water resistance is acceptable though clearly inferior to that of calcium-based greases. However, it can be used in components that are exposed to moisture and water. Therefore, lithium-based greases possess numerous advantages; they can meet both general lubrication requirements and specialized needs, making them an irreplaceable type among current grease products.
Although this temperature is within the range you mentioned, the boss doesn’t agree; the customers will also have their opinions – it’s indeed a bit high
Playing it safe with customers is not a sustainable sales strategy
What I mean is that 75° falls within the range of use for these two types of greases, which indicates that the effect of the grease isn’t very significant. So I’m guessing that either one, too much lubricant was used which prevented heat from being dissipated in time; or two, some impurities might have been introduced accidentally when the lubricant was first applied; or three, it’s still the running-in period for the bearings
Can switching from calcium-based grease to lithium-based grease significantly reduce bearing temperature? Haven’t heard of it. It’s probably because too much grease was applied earlier.