Is it normal for deep groove ball bearings to run hot during initial operation?

It is normal for deep groove ball bearings to have high temperatures during initial operation, which usually occurs during the bearing's running in period. At the beginning of installation and start-up, the contact between the ball bearings, inner and outer rings of the bearing may not be completely smooth, and the distribution of lubricant may be uneven, which can cause certain friction and generate heat, leading to an increase in bearing temperature. This is a common phenomenon, especially at the beginning of bearing operation, where temperature rise is inevitable due to high friction.
During the initial operation, the flow and distribution of lubricant gradually improve, and the surface contact between the rolling elements and the bearing raceway will also undergo a period of running in. The friction force gradually decreases, and the temperature of the bearing will slowly decrease and tend to stabilize. The duration of this running in process depends on factors such as the quality of the bearing, load size, speed, and lubrication conditions. Normally, as the running in process is completed, the temperature will gradually stabilize within a normal range.
It should be noted that although an initial temperature increase is normal, if the temperature rises too quickly or too high (such as exceeding the maximum operating temperature of the bearing), it may be a signal of insufficient lubrication, improper bearing installation, heavy load, or other issues. In this case, the operation should be stopped immediately and the bearings and related systems should be checked.