MRO Magazine

Better lubrication?

MRO Magazine   

Lubrication Machinery and Equipment Maintenance

Problem: I was sure I was lubricating a motor's bearings properly, but they failed anyway. What's up?...

Problem: I was sure I was lubricating a motor’s bearings properly, but they failed anyway. What’s up?

Solution: If it’s a lubrication problem, according to MRO Magazine’s lubrication expert Tex Leugner, the lubricant used was either unsuitable, inadequate or excessive.

To be suitable, it must have the correct viscosity for the application and the operating temperature of the bearing.

If the viscosity is too low, there won’t be an adequate amount of oil film to separate the rolling elements and the raceways, resulting in failure. The optimum viscosity range depends upon bearing RPM, size, type and load.


Excessive lubricant can cause just as much trouble as too little. Oil levels that are too high and excessive quantities of grease in bearings cause an increase in temperature. Same if the viscosity is too high.

But, warns Leugner, about 70% of bearing failures are not lubricant or lubrication related, although they may appear to be.

For accurate solutions, you’ll have to dig deeper. Leugner’s article on test and measurement technologies (see page 21) will help, as will an upcoming feature in our September issue on troubleshooting bearing lubrication problems.

Thanks for this issue’s tip go to Tex Leugner. You can read his troubleshooting advice in every issue of this magazine.

Do you have a solution for a maintenance problem? Send it in and if it’s published, we’ll send you $50 and a free Mr. O Problem Solver T-shirt. Include your address, telephone number, print complete details and, if possible, add a sketch to help explain your tip. Send your tips to Mr. O, Machinery & Equipment MRO, 12 Concorde Place, Suite 800, Toronto, ON M3C 4J2.


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