In This Issue:

• Readers Challenge: What's Your Action Plan?

• Book Bits: Converting Electric Motors to Oil-Mist Lube

• Today's Tip: Advice for Reducing Bearing Failures

• Q & A: Which Greasing Method is Best?

Readers Challenge

What's Your Action Plan?

You take a new job in a facility where lubrication practices are in the stone age. Your job is to bring the lubrication program up to world-class status and machinery failure rates down to earth.

The first thing management wants is a brief action plan. What's your action plan?

Submit your answer at http://www.noria.com/challenge.asp before Monday, January 28, 2003. Lube-Tips editors will choose the best answer and the $50 recipient will be announced next week.

CONGRATULATIONS to Dave Lander, PdM Technician, Temple-Inland Forest Products - the winner of last week's Readers Challenge. See the winning response, as well as other responses at: http://www.lube-tips.com/challenge/

Book Bits

Converting Electric Motors to Oil-Mist Lube

From "Oil Mist Lubrication"

Converting to dry-sump oil-mist lubrication does not necessarily require that the motor be removed and sent to the shop. Motors with regreasable bearings are easiest to convert because they generally incorporate neither oil rings nor bearing shields. Oil rings must be removed because there is, of course, no longer an oil sump from which oil is fed to the bearing. However, recent experience shows that the inboard bearing shield need not be removed to ensure successful installation.

Tests have demonstrated that oil mist did not have to be forced through a bearing, even a double-row thrust bearing. Oil completely fills a bearing housing and contact with the rapidly rotating bearings causes the oil to condense into larger particles.

More information about the book "Oil Mist Lubrication"

Today's Tip

• If you are experiencing premature antifriction bearing failures, you should look at not only your lubrication practices but also your installation practices.
  
  When induction bearing heaters are used, the inner race heats faster than the outer race. This causes a thermal differential between the inner and outer race of the bearing which will reduce the bearing's internal clearance. If this differential is allowed to climb high enough, all internal clearance in the bearing can be eliminated and damage to the balls and races can occur. I have seen the outer races of fairly large bearings burst while they were on the heater as a result of this practice. (Submitted by Shannon Moses, Site Lubrication Engineer, Westinghouse Savannah River Co. Thanks Shannon!)
  

Each tip published will earn the sender $25. Submit your tip.

Q & A

Which Greasing Method is Best?

"What is the correct way to grease electric motors? Some recommend shutting down the motor and opening the drains to allow the old grease to flow out. Others suggest lubricating while the bearing is hot and running."

Greasing rolling element bearings in motors has been an industry problem for years. Electric motor manufacturers differ in their recommended methods of greasing bearings. While some of them recommend that the motor should be shut down for greasing, others allow lubrication when the motor is running.

Our suggestion is to grease your electric motor bearings while running at stable, normal operation temperature. This makes the grease less viscous. Greasing your bearings while running also allows grease to distribute more evenly and helps purge old grease.

Be sure to remove any hardened grease from the drain plug and apply grease to a clean grease fitting. Follow the OEM's recommendations for grease quantity and re-greasing frequency or use ultrasonics for condition-based greasing.

Gerardo Trujillo, senior technical consultant, Noria Latin America

Submit your question here.