3
4.6 Wiring
Connection to the mains is effected direct in
the motor terminal box.
Connect 3-phase motors as shown on the
diagrams in the terminal box lid.
Regarding 1-phase motors see diagrams
for 1-phase adjustable 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 directions
of rotation) a time delay arrangement must
be provided to ensure that the impeller is
stationary before restarting.
Important:
Only fans with steel hubs
may be run in reverse.
Reversible operation
increases risk of fan
stalling. If the fan stalls, the
service life is shortened.
5. Start of operation
5.1 Prior to start of operation
Prior to start of operation check that the fan
and duct connections are clean and free
from tools and foreign substances.
Also ensure 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 complies
with the arrow-plate (check by short-time
operation).
See fig. 7 items 01 and 02.
5.2 Motors with Y/
Δ
starting
The relay must be set to the calculated time.
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
operating speed must not exceed 7
mm/s, rms*, measured radially at
two points, 90° offset and at the free
shaft end of the motor. Otherwise, the
fan must be balanced.
Operation at a vibration level exceeding 11
mm/s, rms*, is not allowed in case of fixed
fan position.
Operation at a vibration level exceeding 18
mm/s, rms*, is not allowed in case of
position on feet or anti-vibration
mountings.
* ISO 2954, 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 in stall area
- 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 Protection prior to
inspection and maintenance
When the fan is out of operation for reasons
of inspection or repair/maintenance, 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 as standard no
maintenance other than ordinary cleaning.
If the fan casing is painted, the painted
surface should be checked regularly and
repaired where necessary.
6.3 Impeller
The impeller (rotor unit) is supplied from
the factory with the blades 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.
Vibrations occurring during operation will
normally be due to accumulations of dust
or dirt on hub and blades, and will
disappear after cleaning. Should this not be
the case, expert assistance should be called
in immediately, as continued vibrations
will shorten the life of the blades and the
motor bearings.
6.4 Motor
The motor normally only requires
maintenance of the bearings as indicated in
the maintenance instructions for electric
motors.
6.5 Dismounting of motor
Prior to commencing the work, switch off
the current and disconnect the motor cable.
Next, dismount any ducts and
downstream guide vane arrangement (fig.
8 items 13, 10, 11, and 14) on the fan outlet
side.
Remove the impeller centre screw (item 09)
and centre disc (item 08).
Dismount the impeller by means of a puller
fastened in the two threaded holes of the
hub boss (item 12).
Detach the motor by loosening the screws
in the motor shell (items 05 and 06). Now
the motor (item 01) and motor flange (item
02) can be removed.
Fig. 7. Novax Type ACG
Fig. 8. Dismounting/mounting of types ACG and ACP
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
