High Axial Vibration at Permanent Magnetic Generator Ball Bearing

[zbiring]

Hi guyz,..
I have problem with pemanent magnetic generator.
Our sistem is turbine (5500RPM)- Gearbox(output-1500RPM)-Generator-Exciter-Permanent Magnetic Generator.

Axial vibration at PMG is about 3-5 times radial direction (dominant at 1XRPM high speed gearbox=5500), PMG rotate at 1500RPM, with spectrum attached. we have replace the bearing and the is not any bearing cocked and nothing change in the amplitude.

is there anyone could help me...?

 

[zbiring]

This peak pass the alarm limit just several days ago. Can it be a resonance?and why it just happen now?
several days ago overall trending was about 5 mm/s (p-p)

Thank You in advance

 

[zbiring]

and the PMG is supported by 2 radial ball bearing.

zbiring

 

[GregLocock]

Can you post the trend in both the axial and radial directions?

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[zbiring]

dear greglocock,

I dont have the software license so I make an excel plot.

any suggestion greg..?

Thank You

 

[zbiring]

axis represent date of measurement from 1(newest date of measurement) to 11 (older date of measurement)

thanks