10
7.3 Checks in plug-fans (optional)
- Electronic plug-fans with variable speed and fl ow sensor that
can be incorporated in supply (models 90 to 360) and return
(models 420 to 600).
- 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.
- The variable-speed plug-fans have a fl ow control pressostat.
This pressostat comes from the factory adjusted to the
indicated fl ow.
- It is possible to readjust the fl ow for diff erent conditions, on
site, by means of the on the pGD1 terminal (see the specifi c
brochure of the CARRIERrtc control, mandatory with this type
of fans).
Motor output up to 15 kW
Motor greater than 15 kW
7 - CHECKING BEFORE COMMISSIONING
For motors up to 15kW it is installed in the factory in the
auxiliary electric panel. For larger motors it is installed next
to the ventilation group.
Pulley and belt calibration
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.
Pulleys must stay on the same plane
Tensor
screw
Pulley
screws
Taper pin
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).
Attention:
Before performing these operations, it is
necessary to verify that the unit is disconnected from
mains.
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
Belt type
f(N)
d (mm)
E (mm)
SPZ
25
56 ≤ 71
2.45
< 71 ≤ 90
2.20
< 90 ≤ 125
2.05
125
1.90
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.
Load to be applied per belt f (N)
Small pulley diameter (mm)
Belt deformation for a pulley centre distance of 100 mm - E (mm)
● 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”.