4
terminal box, check that the rotor
rotation direction complies with the
arrow placed on the outside of the fan.
For ATEX fans the following minimum
airflow rates must be ensured to keep the
ATEX temperature rating.
5. Start of operation
Perform the steps described here every
time the fan has been stopped for shorter
or longer periods.
5.1 Prior to start-up
When the fan is installed and prior to
start-up, check the distances important
for safe operation of the fan. The blade
clearance must be minimum 0.1x motor
shaft diameter (min. 2 mm, max. 13 mm)
all around the rotor circumference.
The axial distance between the rotor hub
and stator must be min. 3.5 mm. Repair
or replace the fan if these tolerances are
not met.
Prior to start-up check that the fan and
duct connections are clean and free from
tools and objects obstructing the airflow.
Also check the electric connections meet
the prescribed requirements, that wire
guards fitted on the inlet or outlet side
are correctly mounted and that the fan
rotates in the direction indicated by the
arrow on the fan casing. Check the latter
by flicking the fan power on and off.
5.2 Motors with Y/
Δ−
starting
The relay must be set to the calculated
time.
5.3 Start-up procedure
Refer to the motor manual for specific
information and procedures.
Start-up procedure
1 Start the fan.
2 Check that no abnormal noise is
present.
3 Check that the vibration level is
acceptable. The vibration level at the
fan operating speed must be less than
7.1 mm/s for motors up to 37 kW, and
4.5 mm/s for motors over 37 kW. This
is measured radially at 2 points, 90
º
offset and at the free shaft end of the
motor. The fan must be balanced. See
section “6.3 Vibration levels”.
4 After 30 minutes of operation check
that the fan operates normally.
6. Maintenance
6.1 Prior to inspection and mainte-
nance
When the fan is out of operation, for
example for inspection or maintenance,
the electric system must be switched off
and secured so that the fan cannot be
unintentionally started.
6.2 Cleaning
Cleaning must be done at least quarterly.
The intervals may have to be adjusted,
dependent on the operation and
operating conditions. Corrosion and
dust filled atmospheres typically reduce
the intervals. Please note that deposits of
dust can be ignited by high surface
temperatures and constitute a safety
risk.
6.3 Vibration levels
After every 1000 hours of operation the
vibration level must be checked. It must
be less than 7.1 mm/s for motors up to
37 kW, and 4.5 mm/s for motors over
37 kW. Investigate and remove the
Motor size
-71
-80
-90
-100
Flow [m
3
/s]
0.07
0.09
Motor size
-112
-132
-160
-180
Flow [m
3
/s]
0.11
0.21
0.47
0.54
Motor size
-200
-225
-250
-280
Flow [m
3
/s]
0.99
1.35
1.47
2.68
Table 6.
Min. airflow rates for ATEX
fans
Important:
The fan is designed for
continuous operation. The
following kinds of
operation may cause
fatigue break in the rotor
and endanger people.
-
Operation in stall area -
Operation with pulsating
counter pressure - called
pump mode
-
Operation with repeated
starting and stopping.
-
Uneven flow velocity
through fan.
If in doubt Novenco should
be contacted to assess the
suitability of the fan.
1 2 3 4
6 7a
9
10
8
5
7b
Figure 8.
Disassembly and assembly
1: Three screws
7a: Nuts
2: Hub cap
7b: Bolts
3: Centre screw
8:
Motor
4: Centre disc
9:
Fan casing
5: Hub boss
10: Guide vanes
6: Rotor
Ø350 hubs
1
2
3
4
6
5 7b
9
7c
10
7b
8
Ø560 hubs
