Practical answer
Common directions include excessive or unsuitable grease, tight fits, insufficient operating clearance, shaft misalignment, seal friction, heat from surrounding components and load or speed beyond the original design. One temperature reading rarely proves the cause.
Record the temperature curve from start-up to stable operation and compare it with similar equipment or historical data. If temperature changed after relubrication, bearing replacement, belt adjustment or overhaul, check that work first.
On-site checks
- Measurement point, ambient temperature and rate of rise
- Grease grade, quantity and last relubrication time
- Fits, clearance, alignment and seal friction
- Actual speed, load and nearby heat sources
Record for enquiry or analysis
- Start-up, 30-minute and stable temperatures
- Any simultaneous change in vibration or noise
- Recent maintenance or operating-condition changes
- Condition of grease and fitting surfaces at shutdown
Suffix rules and allowable values vary by manufacturer. Confirm the final selection against current manufacturer documentation and actual machine conditions. Reference entry points:NSK · Schaeffler medias