3
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.
3 and fig. 4.
The duct or inlet cone on the fan inlet si-
de must be designed to ensure smooth
and undisturbed flow of the air;
ACN-smoke fans are prepared for circu-
lar duct connection on both inlet and out-
let sides.
Flanges supplied as standard
for type ACN comply with EUROVENT
1/2.
Systems with higher vibration level or
more exacting performance require-
ments must be provided with expansion
joints between fan and duct, and ducts
must not be supported by the fan.
It is important to allow for free areas to
facilitate mounting and dismounting as
well as ordinary maintenance.
4.5 Electric connection
Connection to the mains is made accord-
ing to current legislation and by author-
ized personnel.
Connection to the mains is effected direct
in the motor terminal box or in the termi-
nal box mounted on the outside of the
fan casing (see fig. 6). Connection is
made according to connection diagram
on the inside of the terminal box cover.
Having wired the motor terminal box,
check that the direction of rotation of the
impeller complies with the arrow-plate
fitted on the outside of the fan.
5. Start of operation
5.1 Prior to start of operation
Approval (prior to start of operation).
After installation of the axial flow fans
their correct installation, operation and
interaction must be established through
an approval test.
The person responsible for the operation
of the system must take the initiative for
this test.
The approval test must be confirmed by
the person responsible for the operation
of the system and the documentation
must be kept and produced whenever
asked for.
Prior to start of operation check that the
fan and duct connections are clean and
free from tools and foreign substances.
Also check that the electric connections
meet the prescribed requirements, that
any wire guard fitted on the fan inlet or
outlet side is correctly mounted and that
the direction of rotation of the fan com-
plies with the arrow-plate (check by
short-time operation).
5.2 Motors with Y/
Δ
starting
The relay must be set to the calculated ti-
me.
5.3 Starting procedure
• Start the fan
• Check that no abnormal noises occur.
• See that the vibration level is normal.
The vibration level at the fan operat-
ing speed must not exceed 7 mm/s
rms, measured radially at 2 points, 90º
offset and at the free shaft end of the
motor. Otherwise, the fan must be bal-
anced. Operation at a higher vibration
level exceeding 11 mm/ s rms* is not
allowed in case of fixed fan position.
Operation at a higher vibration level
exceeding 18 mm/s rms* is not al-
lowed in case of position on feet or an-
ti-vibration mountings.
• After 30 minutes of operation check
that the fan operates normally.
* ISO 2954, Requirements for instru-
ments for measuring vibration sever-
ity.
6. Maintenance
6.1 Protection prior to inspection
and maintenance
When the fan is out of operation for rea-
sons of inspection or repair/maintenan-
ce, the electric system must be switched
off and protected so that the fan is not cut
in unintentionally.
6.2 Fan casing
The fan casing requires no maintenance
other than ordinary cleaning.
If the fan casing is painted, the painted
surface should be checked regularly and
repaired where necessary.
Figure 3. Installation in duct system
Figure 4. Inlet cone for connection to duct
