Thanks in advance for your reaction.What is causing the dominating vibration 3xfan on this application??
Velocity spectra atached, (mm/s RMS)
# blades fan Aprox 12x-15x
RPM fan 1563 cpm
rpm motor aprox 1490 cpm
I do not have data at this time, but 3A is often 11 mm/s. I analysed the possibility of fan bearings being misaligned. (??).

1H 7,8 mm/s
1V
2H 8,2 mm/s
2V 1,6 mm/s
2A 6,3 mm/s
3H 5,5 mm/s
3V 7,8 mm/s
3A 4 mm/s
4H
4V

Fan_Belt_3x_CPM_Fan.doc (172 Kb, 29 downloads)

Richie

Resonance is the reason, try other speed of fan.
Or follow an slow down, you will see a sharp reduction of vibrations with small reduction in speed.
greetings

I have found 3xRPM when beltwheel was changed to one having 3 spokes... It flexed 0.3mm btw. spokes otherwise for me 3xRPM is a looseness indicator and could be enhanced by resonance, large difference in H/V reading support that also. Olov

quote:

Originally posted by Depauws:
Richie

Resonance is the reason, try other speed of fan.
Or follow an slow down, you will see a sharp reduction of vibrations with small reduction in speed.
greetings

Tanks for your comment. It's difficult to change the machine speed, but I wil watch it when it is powering down. Sorry for replying so late, but I've been bizzy. Thanks again, and i will let you now when the problem is solved.
Richie

quote:

Originally posted by OLI:
I have found 3xRPM when beltwheel was changed to one having 3 spokes... It flexed 0.3mm btw. spokes otherwise for me 3xRPM is a looseness indicator and could be enhanced by resonance, large difference in H/V reading support that also. Olov

Tank you also for your reaction Olov, I will let you know how this story ends,
Richie