On testing an uncoupled, 2 pole (3000 RPM, 50 Hz) motor on sleeve bearings, I found the following axial vibration frequencies (mm/sec RMS) on DE bearing top cover.
Overall - 3.91 mm/sec RMS
0.04 at 1500 RPM
0.89 at 3000 RPM
3.00 at 6000 RPM
0.05 at 9000 RPM
0.07 at 12000 RPM
I confirmed it is not electrical vibration since the overall DE axial vibration did not drop immediately upon cutting off the motor supply. The motor test bed is a machined bed in which I have tested many high speed motors successfully, so no bed issues.
The overall axial vibration in NDE bearing top cover was only 1.5 mm/sec RMS. (I see normally axial vibrations on both bearings are almost the same).
Vibrations in DE & NDE Horizontal and Vertical were also less than 1.5 mm/sec RMS.
Any reasons why this high 2X axial vibration only in DE bearing ?
I am also posting this in electrical forum to get their views, so don't RF me.
Muthu
Overall - 3.91 mm/sec RMS
0.04 at 1500 RPM
0.89 at 3000 RPM
3.00 at 6000 RPM
0.05 at 9000 RPM
0.07 at 12000 RPM
I confirmed it is not electrical vibration since the overall DE axial vibration did not drop immediately upon cutting off the motor supply. The motor test bed is a machined bed in which I have tested many high speed motors successfully, so no bed issues.
The overall axial vibration in NDE bearing top cover was only 1.5 mm/sec RMS. (I see normally axial vibrations on both bearings are almost the same).
Vibrations in DE & NDE Horizontal and Vertical were also less than 1.5 mm/sec RMS.
Any reasons why this high 2X axial vibration only in DE bearing ?
I am also posting this in electrical forum to get their views, so don't RF me.
Muthu
