How to judge whether the grease of Precise rolling mill Motor needs to be replaced?

1. Appearance inspection
Color change: Normal grease is usually milky white or light yellow, and the color is uniform. If the grease is found to be black, dark brown or other abnormal colors, it may be due to the mixing of metal particles produced by bearing wear, or the oxidation and deterioration of the grease at high temperature. For example, when the motor is overloaded for a long time and the temperature is too high, the grease is easy to oxidize and the color will gradually darken.
Texture change: Dip a small amount of grease with a clean tool for observation. Normal grease has a soft, delicate texture and a certain viscosity. If the grease becomes dry, agglomerated or granular, it means that the grease has lost its lubricating properties. This may be because the grease has been in a high temperature environment for a long time, the water evaporates, or it is contaminated by chemicals.
2. Performance test (if conditions permit)
Dropping point test: The dropping point refers to the temperature at which the grease changes from solid to liquid. A professional dropping point tester can be used for detection. If the actual dropping point of the grease is significantly lower than its nominal value, it means that the performance of the grease has declined. For example, if a grease with a nominal dropping point of 180°C has a dropping point lower than 160°C in actual testing, it may be that the composition of the grease has changed and needs to be replaced.
Cone penetration test: Cone penetration is an indicator of grease consistency. The cone penetration of grease is measured by a cone penetration meter. If the cone penetration is much larger than the initial value, it means that the grease has become softer, which may be mixed with other impurities or base oil separation; if the cone penetration decreases, it means that the grease has become harder and the fluidity has deteriorated, and it cannot effectively lubricate the bearing.
3. Operation status monitoring
Temperature change: During the operation of the Precise rolling mill Motor, the bearing temperature is an important reference indicator. If the bearing temperature rises significantly under normal load and speed, and other factors (such as overload, poor ventilation, etc.) are excluded, it is likely that the grease has failed. For example, if the bearing temperature of a motor that originally ran stably rises from the normal 40-50°C to 70-80°C, it is necessary to check whether the grease needs to be replaced.
Vibration and noise: When the grease is insufficient or deteriorates, the friction of the bearing will increase, causing the motor to vibrate more and produce abnormal noise. Vibration sensors and noise testers can be used to monitor the vibration and noise of the motor. If the vibration amplitude of the motor exceeds the normal range (usually the standard value provided by the motor manufacturer), or there is abnormal noise such as sharp friction and humming, it may be caused by grease problems, which requires further inspection and consideration of grease replacement.