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Ventus Air Handling Units
Table 19 Deflection power value P* depending on type and diameter „d
P
” of the smaller wheel
SPZ
SPA
SPB
Diameter of the smaller pulley d
P
[mm]
67-95
100-140
100-140
>140
160-236
>236
Deflection force P* [N]
10-15
15-20
20-27
28-35
35-50
50-65
Deflection force P* [Kg]
1.0-1.5
1.5-2.0
2.0-2.7
2.8-3.6
3.6-5.1
5.1-6.6
*power required to deflect a belt by s=16mm at wheel spacing A=1000mm
In order to eliminate redundant calculations, a diagram with belts deflection values „S" have been
provided with various Axle base of pulleys.
Fig.25 Deflection of wedge-shaped belt depending on axle base of the pulleys
Also check if the wedge-shaped belt is not broken, cracked, dried or damaged in any other way.
Damaged wedge-shaped belt must be replaced. In case of multi-belt drive, even if just one belt is
worn out, you have to replace all the belts making sure that they have the same length and fit the
grooves of the pulley. If you do not replace all the belts, the new ones will transfer bigger overloads
since they are a bit shorter than the old ones. During belts replacement ease the stretching screws of
the motor panel (fig.26) so that the belts can be removed and replaced with new one manually
without applying force. In no circumstances you are allowed to install the belts by force, with a
screwdriver or with any other tool. During belt replacement check if the pulleys' contact surfaces are
not worn out. New belts should be stretched so as the required deflection force P (fig. 24) was as
close to the P value shown in the table 18 as possible.
Once the new belts are assembled, verify the pulleys' alignment, checking with a gauge if they are
parallel to each other and if their groves are in a line. (fig. 27). Once they are adjusted, rotate the
drive without any load to allow the belts to lay down in the grooves accurately. New belts should be
stretched again after 50 hours of operation.
Axle base of pulleys A [mm]
V
b
e
lt
d
e
fl
e
ct
io
n
S
[
m
m
]
