SPX Cooling Technologies MARLEY 07-1126 - Manual (Page 15)

15
Maintenance
9––Worn output shaft bearing: this condition generates vibration on
the tip path plane at a frequency equal to the rotor RPM.
10––The fan and/of the structure bolts are not tightened: in this case
all the bolts have to be tightened.
11––The draining holes of the blades are obstructed: they have to
be opened.
The amplitude of the fan vibrations is determined by the rigidity
of its support. Vibration that would not be critical to a fan sup-
ported by a sufficiently rigid structure is amplified by an overly
flexible support. This support rigidity may also cause unexpected
variations in the resonant frequencies of the blades.
Note