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8 - CHECKING BEFORE COMMISSIONING
Checks in the centrifugal fan: STD version
■ Before commissioning, check the blade rotation direction and
that the axis turns without strokes nor vibrations
■ Once running, check the operation conditions: pressures, fl ows
and consumptions.
■ The coupling of characteristic curves of the fan and the room
is very important, so that the fl ows and pressures provided to
the duct network are as required.
Pulley and belt calibration
Attention: Before performing these operations, it is necessary to
verify that the unit is disconnected from mains.
The centrifugal motorfans are coupled through pulleys and belts.
In these fans, the following must be taken into consideration:
Pulley alignment:
■ The pulleys must be on the same plane, so it is important to
check them with the help of a ruler or a laser aligner.
■ In case they are not aligned, remove the pulley screws, and
after removing the taper pin, the set of pulley and taper can be
slided over the axis (this action can be performed both in the
motor as well as in the fan).
Tensor screw
Pulleys must stay on the same plane
Pulley
Taper
screws
pin
Belt tension:
After fi xing the pulleys on the same plane, the belt tension is made
by tightening the tensor screw.
Excessive tension on the belt can lead to premature wear on the
assembly. Insuffi cient belt tension can cause slippage, overheating
and premature wear of the belt.
It is essential to tension the belts using the "Defl ection test"
described below:
■ The belt tension must be checked and corrected using a suitable
measuring instrument (tensiometer or dynamometer)
■ "Ea" calculation:
- Ea = (e x E)/100 = deformation in mm for a pulley centre
distance of 100 mm
- e = pulley centre distance in mm
- E = see table below for the value
- f = force applied
■ At the centre of the centre distance "e", apply a force "f", as
determined in the table below, to each belt. Set the belt tension
to obtain the calculated defl ection "Ea".
E
Belt
f(N)
d (mm)
(mm)
type
56 ≤ 71
2.45
< 71 ≤ 90
2.20
SPZ
25
< 90 ≤ 125 2.05
125
1.90
Load to be applied per belt f (N)
Small pulley diameter (mm)
Belt deformation for a pulley centre distance of 100 mm - E (mm)
Important: During commissioning, the belt tension must be
checked after 48 hours of operation.
The belt tension must be checked in all cases and before system
start-up.
Checks on the plug-fan: HEE version
■ Before commissioning, check the blade rotation direction and
that the axis turns without strokes nor vibrations
■ Once running, check the operation conditions: pressures, fl ows
and consumptions.
■ The coupling of characteristic curves of the fan and the room
is very important, so that the fl ows and pressures provided to
the duct network are as required.
9
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