Electric Motor Bearing Grease Selection

Grease relubrication intervals for normal operating conditions can be read as a function of bearing speed.

Electric motor bearing grease selection.

Electric motor bearing greasing requires the motor to be de energized during the procedure. Regularly greasing your electric motor bearing is an important part of electric motor maintenance. The result is reduced risk of excess grease entering the electric motor stator due to couetti flow and reduced viscosity due to heat. This too is highly influenced by bearing selection.

While most would not use an ep 220 gear oil for an oil lubricated electric motor bearing many people will use a grease containing that same oil for an identical grease lubricated bearing. Run the motor for at least 20 minutes to purge any excess grease and then replace the drain plug. 3 c p load ratio where c basic dynamic load rating kn and p equivalent dynamic bearing load kn. Able to handle light to moderate loads at high speeds this grease is often used on electric motor bearings for fans pumps and dryers.

1 rotational speed rotational speed r min x 0 5 d d mm. Nlgi 2 is about the consistency of peanut butter. Viscosity oil viscosity should be appropriate for the load and speed of the application at operating tempera ture. With the motor running pump fresh grease into the bearing while observing the old grease that is being forced out of the grease drain.

This will help to insure maximum. When applied correctly the right grease will protect your electric motor s bearing against damaging corrosion reduce wear caused by friction and act as a seal against contaminants. When the purged grease looks fresh stop pumping. Nlgi 3 is about the consistency of vegetable shortening.

Combined with safety issues proper lubrication can maintain the electric motor reliability. Nlgi viscosity grade is a rating of a grease s consistency. These include incorrect lubricant selection contamination loss of lubricant and overgreasing this article discusses several effective strategies to minimize the likelihood of these failure modes. Because the majority of grease lubricated applications are element bearings one should consider viscosity selection for those applications.

And since 40 to 70 of motor failures are related to bearings it s no surprise that high quality bearings are key for reliable motors. But choosing the right bearings alone isn t enough. Mineral oil based grease derived from petroleum is more economical than synthetic oil. Another crucial factor for electric motors is energy efficiency.

Choosing the right electric motor grease important grease characteristics for electric motor bearings the following criteria may be used as typical indicators of a good electric motor grease.