3
When the fan has been finally secured
make sure that the rotor rotates freely in
the casing.
If the motor is provided with drain holes
for condensed water the fan must be ori-
ented so that the holes turn downwards
(lowest point).
Generally, it is of the utmost importance
for the performance and sound level of
an axial flow fan that the airflow is un-
impeded and free from eddies.
4.3 Support frames and dampers
The ACN-ARN smoke fans can all be fit-
ted with either horizontal or vertical sup-
port frames.
Horizontal support frames consist of
two mounting plates (see fig. 2, item 01),
which are joined with stiffeners and
screws (items 02 and 03). The stiffeners
are used with fan sizes Ø630 and up.
Vertical support frames are mounting
plates onto which the fans are flange
mounted.
Anti-vibration dampers with base plates
(accessories) prevent spread of vibra-
tions from the fans to the surroundings.
See fig. 3, items 06 and 07 and fig. 4. With
the dampers the natural system frequen-
cy is kept below 10 Hz. The damping is
at least 80% at 1500 RPM.
The anti-vibration dampers install be-
tween the fans and the supporting foun-
dation. Installation of base plates (item
07) between the dampers and founda-
tion is optional, but recommended de-
pending on the type of surface.
Secure anti-vibration dampers to the
support frames by means of bolts.
Flexible connections (accessory) may be
fitted in the ducts before and after the
fans. See for example fig. 4.
4.4 Duct connection
In order to achieve the capacities stated
on the performance curves the fans must
be provided with ducts as shown in fig.
5 and fig. 6.
The duct or inlet cone on the fan inlet
side must be designed to ensure smooth
and undisturbed airflow. ACN-ARN
smoke fans are prepared for circular duct
connection on both inlet and outlet sides.
Flanges supplied as standard for type
ACN-ARN comply with Eurovent 1/2.
Systems with higher vibration levels or
more exacting performance require-
ments must be provided with expansion
joints between fan and duct. Ducts must
not be supported by the fan.
It is important to allow for free areas to
facilitate mounting and dismounting as
well as maintenance.
4.5 Electric connection
Fans with frequency drives must be in-
stalled in accordance with the EU stand-
ard for electromagnetic compatibility
(EMC). The shielding and connection to
ground eliminate interference and pro-
tect the fan motor bearings and wind-
ings. Refer to the motor documentation
for methods to avoid impairment of the
mains power quality. Prescribed meth-
ods may involve installation of rectifiers,
filters etc.
Connection to the mains is effected di-
rectly in the motor terminal box or in the
terminal box mounted on the outside of
Important:
Support frames must be
grounded to prevent
electrical shocks.
Figure 4. ACN with vertical support frame
(left) and with flexible connection and anti-
vibration dampers
Important:
The natural frequency of
the support must be min.
20% from the fan speed.
Important:
The electric installation of
fans intended for smoke
exhaust that are fitted
with frequency drives,
must be designed to
bypass the frequency
drives and run the fans at
nominal speed in the
event of fire.
Important:
The installation and
connection to the supply
network must be done by
authorised personnel and
in accordance with
current legislation.
Figure 5. Installation in duct system
Figure 6. Inlet cone for connection to duct
