What EASA Tech Note Covered Roller Bearings? 2

[dArsonval]

A couple of years ago, EASA published a "Tech Note" regarding the
preferred method(s) of installing, and test operating a motor with
a roller bearing installed in [it] etc. I don't have access to
this data right now. Is there a willing participant among the crowd
here that can authenticate what EASA tech note issue pertained to
test running a motor with a roller bearing installed at the drive
end... and the information regarding the motor being tested to be
under a load before applying power to the motor?

Any other info regarding roller bearing issues related to
electric motors certainly would not hurt being rekindled.

Thank You in Advance for any, and all of your replies to this
age old question.

John

 

[electricpete]

fwiw, I think your options are:
1 - Add a side load somehow
2 - replace cylindrical bearing with deep groove for the test run.
3 - don't run it too long (like maybe limit run to 15 minutes... just enough to grab vibration data and currents etc).
Also I vaguely recall someone suggesting if you have to run CRB without load that there may be some things you can do to improve the lubrication to minimize skidding... like either warming the bearing prior to running the machine, or add a drop of oil into greased bearings.

Then again, if I were you I'd wait for someone to tell what EASA says.




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(2B)+(2B)' ?

 

[starkopete]

Hi, EASA had two articles pertaining to test running motors with roller bearings:

Preloading Roller Bearing Motors For No-Load Run Testing, by Kirk Kirkland, in the Feb. 2010 EASA Currents

Tips For Test Running Motors With Roller Bearings, by Nancy Nyberg, in the July 2006 EASA Currents

I am attaching our current procedure for running roller bearing motors. I am also including pictures of the apparatus that we use, it is a high load range, high speed wheel and spindle with a hydraulic jack and a load cell.

Thanks

 

[starkopete]

This is the set-up that another shop uses.

 

[edison123]

Isn't self weight of the rotor enough of a preload for the bearings ? Moreover during actual running of the motor, there is no such externally applied radial preload.

Muthu

http://www.edison.co.in

 

[starkopete]

edison123:
If you look at my attachment at 3 MAR 11 9:10 you'll see it includes a chart from SKF for the minnimum load on roller bearings. The load is required to prevent 'skidding' of the rollers along the race. You are correct about the rotor itself being sufficient load in a lot of cases. When we balance the rotors we wiegh them, if half the wieght of the rotor does not exceed the minnimum load required for the bearing we know we have to add an external load.

Thanks

 

[electricpete]

You could evaluate for the specific case as above.

I think as a general rule, most medium / NEMA frame size motors with cylindrical roller bearings on inboard end are designed for belted applications and would be underloaded without the belt. It may not apply to larger motors.


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(2B)+(2B)' ?