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Operating Checks
Too low a belt tension can cause belt slipping and prema-
ture wear. The following table indicates force "F" to mea-
sure the belt tension in relation to the smaller pulley type
and diameter. The following chart shows the relationship
between the belt slack "S" and the distance between the
pulley axes "A".
Table 2 – Belt tensioning forces
Belt
Small pulley
profile
diameter
*The force needed to deflect the belt to achieve 16 mm belt slack at a
distance between pulley axes of A = 1000 m
Chart 1 –
Belt slack „S" and pulley axes distance „A"
&
$
"
&
$
"
!
#
After replacing and tensioning the belts or pulleys, it is
necessary to check the alignment of the pulleys (use
a metal ruler).
Figure 26 – Pulley alignment
wrong
correct
Table 3 – Tightening torques for metric screws
M4
M5
M6
2,8 Nm
5,5 Nm
9,5 Nm
Table 4 – Taper-Lock collet tightening torques
1008 1108 1210 1610 1615 2012 2517 3020 3030
5,6
5,6
20
20
16
Recommended force
to deflect the belt [N]*
relation
F
%
'
!
A (mm)
M8
M10
23 Nm
46 Nm
79 Nm
20
30
50
90
90
Air Handling Units
Taper Lock collets enable alignment of the pulleys.
Figure 27 – Taper Lock® collet
Assembly
Disassembly
Maintenance and lubrication of ADH-RDH double-
inlet fans equipped with a spiral fan casing and belt
drive
All maintenance operations and lubrication must be per-
formed using suitable tools and implements.
First check the bearings by listening to them. If the bea-
rings are in good condition they will generate a slight and
constant noise while defective bearings will generate a
loud and irregular noise. A low metallic noise, which is
caused by the standard allowances between components,
especially at low speed, is normal. Excessive vibrations
and increased temperature of bearings indicate a possib-
le defect. It is also necessary to check the mounting of
the fan bearings in their casings for integrity and also for
excessive lubricant leakage. Moderate leakage of lubri-
cant, especially during fan commissioning, is normal and
has no negative influence on fan operation. Estimated
mechanical service life of bearings installed in the ADH/
RDH Nicotra fans is 40000 hours providing the fans were
selected considering their operating limits, the environment
and planned drive size.
M12
Taper-Lock
3525 3535 4030 4040 4535 4545 5040 5050
Tightening torque (Nm)
115
Before collet and pulley assembly,
carefully clean the inner collet opening
and taper surface.
Insert the collet into the pulley hub so
that the threaded openings will check
with the openings without thread.
Tighten the fixing screws by hand.
Carefully clean the shaft, and place the
pulley in the required position. Tighten
the fixing screws alternately with the
prescribed tightening torque.
Loosen the fixing screws, and insert one
or two of them as force-off screws (accor-
ding to the collet size) into the withdrawal
openings. Knock slightly on the pulley.
Keep tightening the force-off screws until
the collet is released from the pulley.
115
170
170
190
190
270
270
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