MacMcMacmac
Aerospace
- Sep 8, 2010
- 56
Good Day folks. I have recently experienced the failure of a drive end bearing on a 1350hp, 1750rpm drive motor, powering the first stage of a 2MW exhauster through a gearbox.
This motor was overhauled in 2019. It has not been run very extensively since we are in a research facility which has highly variable operating hours.
These bearings were replaced at overhaul. I have no idea on how, or how well they were packed at install. There was a short 3/8" pipe nipple, a 90 elbow and a zerk fitting installed at the time of reassembly to ease access to the grease port.
I was operating the exhauster last week when i heard a sudden growling/moan emanate from the machine. The DE vibes spiked and settled, before spiking a second time. I observed the machine and saw a hazy smoke appearing in the machine hall, so I e-stopped the exhauster immediately. Coast down went smoothly. Bearing temperature spiked to 180F. It was obvious from our temperature readout screen that it was the point of failure since it was the only component in the red.
Upon disassembly, I was disappointed to find that the grease inside the fitting had reached the bend in the elbow and no further. I probed the grease port and found almost nothing. Granted, I had probably not reached the bearing per se, but it was definite evidence that these bearings had not been successfully greased since install. I checked the zerk, and while a battery powered gun would not force grease through, a manual gun did successfully operate the fitting. So, possible failure point there. There was a glob of grease on the exterior of the zerk, so an attempt was made to lube it, albeit unsuccessfully.
There is a vent port at the bottom of the bearing housing. My main question is this, is it acceptable to fully grease this bearing after it has been replaced so that there is fresh grease coming out of the vent port at the bottom of the case, or am I at risk of over-greasing the bearing and causing a different set of problems? I have no data on how much to add. The bearing is a 22222E-c3 double row spherical roller bearing on the drive end of the motor.
Unfortunately, there is an identical motor next to it, overhauled at the same time at the same facility that I now have to worry about. There is a very important test campaign coming up in a few months and this is definitely not something we need to worry about for the duration. It is likely both motors will be treated to new bearings, but I still need to know if I can fully flood these bearings with grease. Are automatic grease applicators a good or bad idea? Thank you for any help you can give.
This motor was overhauled in 2019. It has not been run very extensively since we are in a research facility which has highly variable operating hours.
These bearings were replaced at overhaul. I have no idea on how, or how well they were packed at install. There was a short 3/8" pipe nipple, a 90 elbow and a zerk fitting installed at the time of reassembly to ease access to the grease port.
I was operating the exhauster last week when i heard a sudden growling/moan emanate from the machine. The DE vibes spiked and settled, before spiking a second time. I observed the machine and saw a hazy smoke appearing in the machine hall, so I e-stopped the exhauster immediately. Coast down went smoothly. Bearing temperature spiked to 180F. It was obvious from our temperature readout screen that it was the point of failure since it was the only component in the red.
Upon disassembly, I was disappointed to find that the grease inside the fitting had reached the bend in the elbow and no further. I probed the grease port and found almost nothing. Granted, I had probably not reached the bearing per se, but it was definite evidence that these bearings had not been successfully greased since install. I checked the zerk, and while a battery powered gun would not force grease through, a manual gun did successfully operate the fitting. So, possible failure point there. There was a glob of grease on the exterior of the zerk, so an attempt was made to lube it, albeit unsuccessfully.
There is a vent port at the bottom of the bearing housing. My main question is this, is it acceptable to fully grease this bearing after it has been replaced so that there is fresh grease coming out of the vent port at the bottom of the case, or am I at risk of over-greasing the bearing and causing a different set of problems? I have no data on how much to add. The bearing is a 22222E-c3 double row spherical roller bearing on the drive end of the motor.
Unfortunately, there is an identical motor next to it, overhauled at the same time at the same facility that I now have to worry about. There is a very important test campaign coming up in a few months and this is definitely not something we need to worry about for the duration. It is likely both motors will be treated to new bearings, but I still need to know if I can fully flood these bearings with grease. Are automatic grease applicators a good or bad idea? Thank you for any help you can give.
