Which of the following is a cause of heat buildup in a bearing along with misalignment?

• A. Overloading
• B. Lack of lubrication
• C. Excessive vibration
• D. Poor cooling

Answer: (A)

Heat buildup in a bearing comes from the friction between moving parts converting mechanical energy into heat. When a bearing is misaligned, the load is not evenly carried, causing higher local contact stresses and more edge loading. This increases sliding friction and wear, so heat rises even with normal lubrication. If you also overload the bearing, those contact stresses rise even further, the rolling elements may experience greater slip or skid, and the lubricant film can be squeezed out faster. The combination of misalignment and overload dramatically amplifies friction and heat generation, making overheating more likely. Other factors like inadequate lubrication, excessive vibration, or poor cooling can also cause heating, but overloading specifically intensifies the heat when misalignment is present.