Performance Characteristics of Lubricating Greases in Ball Bearings at Elevated Temperatures

Pope method of testing grease

ASTM D3336, FTM 331/333 (Pope Test)

Purpose

Evaluate grease evaporation and oxidation resistance in a lightly loaded, high speed, heated ball bearing.

Brief Description

A 204 K ball bearing (photo insert) is packed with 3.2 cc of grease and rotated at 10,000 rpm under light loading while heated to 150°C, 177°C, or other test temperatures. The test cycle is 20 hours of running and 4 hours at rest. When electrical current to operate the spindle motor increases by 300% of the value of the newly packed bearing, testing is stopped and the number of running hours is the test result. This test is named for the builder of the high speed spindle, Pope Spindle Co. Satisfactorily performing greases have low viscosity base oils that resist evaporation and oxidation and that readily release oil.

The information presented in this article was originally derived from a publication from Mobil, and is presented here for information only. Please consult with your Certified Lubrication Specialist to ensure proper testing is done.