3
performance and sound level of the axial
flow fan that the air flow is unimpeded and
free of eddies.
4.5 Duct connection
Novax ACG Smoke axial flow fans are
equipped with an outlet guide vane
assembly with core. This improves fan
efficiency and allows duct connection.
The duct on the outlet side of the fan must
be designed to ensure a smooth flow of air
without turbulence. Avoid, for instance,
sharp bends or flexible connectors in the
ducting immediately behind the fan.
ACP and ACG Smoke fans are prepared for
circular duct connections on the outlet side.
Flanges supplied as standard comply with
EUROVENT 1/2.
Systems with higher vibration levels or
more exacting performance requirements
must be provided with expansion joints
between the fan and duct, and the duct
must not be supported by the fan.
It is important to provide sufficient free
space for assembling and dismantling the
system and to facilitate cleaning and
maintenance.
4.6 Wiring
Important:
Do not mount a frequency
converter on a fan intended
for smoke exhaust. The
electric installation must be
designed to bypass the
frequency converter and run
the fan at nominal speed in
the event of fire.
Electrical connections must be made by an
authorised electrician in accordance with
current legislation. Power is connected via
the motor terminal box as shown in the
wiring diagrams in the terminal box cover.
Three-phase motors are connected as
shown in the wiring diagrams in the
terminal box cover.
For the connection of single-phase motors,
see wiring diagrams for single-phase
variable motors.
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.
For reversible fans (alternating direction of
rotation) a time delay must be provided to
ensure that the impeller is stationary before
restarting.
5. Start-up
5.1 Before start-up
Before start-up, check that the fan and duct
connections are clean and free of tools and
other foreign matter.
Also ensure that the electrical connections
fulfil applicable requirements, that any
protective grilles on the fan inlet or outlet
sides are correctly fitted, and that the
direction of rotation of the impeller
complies with the arrow plate (check by
briefly starting the fan).
See fig. 7 pos. 01 and 02.
5.2 Motors with Y/
Δ
start
The relay must be set to the calculated time.
5.3 Start-up procedure
• Start the fan.
• Check that no abnormal sound occurs.
• Check that the vibration level is
normal. At operating speed, fan
vibration must not exceed 7 mm/s
rms* measured radially at two points
with 90° offset and at the free shaft end
of the motor. Otherwise, the fan must
be rebalanced.
When fixed in position, the fan must not be
operated if vibration levels exceed 11 mm/
s rms*.
When freely suspended or mounted on
vibration dampers, the fan must not be
operated if vibration levels exceed 18 mm/
s rms*.
* ISO 2954: Mechanical vibration of rotating
and reciprocating machinery –
Requirements for instruments for
measuring vibration severity.
After thirty minutes of operation, check
that the fan operates normally.
Important:
The fan is designed for
continuous operation. The
following kinds of operation
may cause fatigue break in
the impeller and endanger
people.
- Operation with pulsating
counter pressure - called
pump mode
- Operation with repeated
starting and stopping
If in doubt Novenco should
be contacted to assess the
suitability of the fan.
6. Maintenance
6.1 Safeguards prior to
inspection and maintenance
Before inspecting or servicing the fan, it
must be switched off and disconnected
from the electrical system. Also ensure that
the fan cannot be restarted unintentionally.
6.2 Fan housing
As standard, the fan housing requires no
maintenance other than cleaning.
If the housing is painted, the surface should
be checked regularly and repaired where
necessary.
6.3 Impeller
The impeller (rotor unit) is supplied with
the blades factory adjusted to the pitch
corresponding to the desired operating
point (pressure and air flow) at the fan
speed in question. To ensure vibration-free
operation the impeller has been carefully
balanced in this position.
Vibration occurring during operation is
usually the result of dust or dirt
accumulating on the hub and blades, and
Fig. 7. Novax ACG Smoke
Fig. 8. Dismantling/assembling types ACG and ACP Smoke
1. Motor
2. Motor flange
3. Wire guard
4. Motor shell
5. S-washer
6. Set screw
7. Impeller
8. Centre disc
9. Centre screw
10. Set screw
11. Washer
12. Hub
13. Outlet guide vanes
14. Nut
