Howden 24-07.030r04 17/25
E-series Axial Flow Cooling Fans
g. Immediately after first start up check for
smooth operation of the fan assembly.
Check for irregular noise / vibrations.
Howden adopts the guideline given in
standard ISO-14694 describing the
acceptable vibration levels. The “in situ”
vibration level of any fan is not solely
dependent on the balancing grade.
Installation factors, the mass and stiffness
of the supporting system, will influence the
in situ vibration level. Therefore, fan
vibration level “in situ” is not the
responsibility of the fan manufacturer
unless specified in the purchase contract.
ISO-14694 classifies fans according to
their application and drive power. Howden
cooling fans are in general used for
industrial processes, power generation
and HVAC with a drive power level up to
300 kW. According ISO-14694 Howden
cooling fans are classified in the so-called
fan application category BV-3.
For fans in application category BV-3
balancing grade G6.3 is recommended
(ISO-14694) and therefore Howden
cooling fans are balanced according to
this balancing grade. The vibration levels
given in table X are a guideline for
acceptable operation of Howden cooling
fans.
Immediately after commissioning the
vibration level has to be below or at the
given start-up value. When the vibration
level increases to alarm level investigation
to the cause of this level has to be initiated
and action taken to correct it. When the
vibration level increases to shutdown level
corrective action should be taken
immediately or the fan should be shut
down.
The vibration limits shown in table X apply
to assembled fan units. The values shown
are velocity, in millimetres per second
(mm/s). Filter-In, at fan rotational
frequency and are to be taken at the fan
bearings or at gearbox sides as per figure
19, in case the fan is mounted directly on
the gearbox shaft.
Figure 19 Vibration Measuring Points measured at Fan
Units of Air Cooled Condensers
Possible Measuring Points
Gearbox - lateral flange - horizontal
Gearbox - front end - horizontal
Gearbox - bearing cover of output shaft - vertical
To Next Page
Loading...
