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Originally Posted by oil pan 4
The grease in bearings causes more resistance than you think.
I never had a good way to measure the difference in a bearing that was worn in versus one freshly filled with grease. Until now...
Where I work now we have hundreds of motors, many of which run 24/7, all motors have amp draw closely monitored, the amp draw is even recorded an its trend can be viewed on demand. Some of the motors have vibration monitors installed too.
On the high speed blower motors that run pretty much at the same speed all the time at high speed I have found that when I pump grease into these bearing the motor amp draw can go up by as much as 15%.
Even the large 500 horse power turbo fan motors that run around 3400rpm see a 5% increase in amp draw.
They stay like this for several hours after greasing. I guess they continue to draw more power till the extra grease works it way out.
Next step will be to go to the motor control room and see what the voltage is and determine the actual horse power draw that increase.
At the same time I will be looking for motors that like to run around 600 to 900 RPM (about the same speed as your cars tires on the highway) and see the effect of a load of grease on the bearings.
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Is this a ball bearing or bushing? After some reading online it would appear ball bearing can be over filled. How do you determine when and how much and what type to use? While the reference was to sealed bearings, this may be true of all types.
The time for the motor to return to normal draw may be related to several factors, the fill and operating temperature come to mind.
Quote:
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Too much grease leads to excessive churning, high temperatures, and severe grease degradation
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http://www.stle.org/assets/document/...g_Bearings.pdf