What is ISO 21250-3 about?
ISO 21250-3 is the third part of the multi-series of International Standard on rolling bearings.
ISO 21250-3 is applicable to the rolling bearings for noise testing of rolling bearing greases through the testing and evaluation method of rolling bearing grease noise in accordance with the method MQ.
Who is ISO 21250-3 for?
ISO 21250-3 on noise testing of rolling bearing greases is useful for:
- Manufacturers of rolling bearings
- Automotive industry
- Lubricant manufacturers
- Electrical engineers 
- Mechanical engineers
Why should you use ISO 21250-3?
The rolling bearing life theory emphasizes the use of pure and homogeneous lubricants as essential for a long bearing service life.
The method described in ISO 21250-3 for determining the purity grade of bearing grease is influenced by thickeners, base oils, additives, and solid lubricant additives, as well as the manufacturing process, and this is reflected in the running noise. As a result, rolling bearing grease noise testing is advised.
ISO 21250-3-compliant grease noise testing enables grease makers to design low-noise lubricants with improved damping qualities. ISO 21250-3 can also help rolling bearing manufacturers and end-users choose low noise grease with improved damping qualities.
ISO 21250-3 specifies the requirements for the testing assembly and test machine used in method MQ to jointly determine and assess the noise characteristics of rolling bearing grease.
Unlike the BQ+ method, the procedure of MQ requires test bearings to be greased manually. That said, friction and wear are kept to the minimum which helps avoid product failure.
Overall, compliance to ISO 21250-2 will assist you in determining the quality of grease noise or selecting low-noise (quieter) greases. Ultimately, you will be able to avoid incidence of high fatigue life of bearings. If you are a bearing producer, ISO 21250-2 will help you select the right grease.
