ZerAx
®
axial flow fan types AZL-AZN-AZW
7
6.7 Motor removal
Switch off the power and
disconnect the motor cable in
the terminal box, before
beginning work on the rotor and motor.
For fans with PM motors, make sure the
motor axles cannot rotate during
service, e.g. by blocking the fan rotors.
PM motors can generate high voltages
when the motor axles rotate, even
though the power is disconnected.
The below procedure is with reference to
figures 14 and 15 beginning on page 12.
Motor removal
1. Dismount any ducts on the inlet and
outlet sides.
2. Remove the screws (item 1) that hold
the hub cap and remove the cap (item
2) itself.
3. Remove the rotor centre bolt and
washers (item 3).
4.
Fans with hub clips:
Remove the hub
clip, screws and washers (item 4).
5. Dismount the rotor with a puller
fastened in the threaded holes of the
hub boss (item 5).
6. Disconnect the motor cable from the
motor.
7. Support the motor. See table 11 on
page 11 for max. motor weights.
8. Detach the motor from the motor shell
by removing the nuts and bolts (items
7a and 7b) for hub sizes Ø350 and
Ø560, or bolts and washers (items 7b
and 7c) for hub sizes Ø160.
Notice:
Nuts holding motors
mounted in rear motor
shells are accessed through
the front motor shells.
9. Remove the motor (item 8).
Avoid exposure of fans and
motor parts to shocks, as these
can result in imbalance and
deformations. Motor bearings and fan
components are vulnerable parts.
6.8 Mounting of motor
Replace lock washers and nuts
during assembly.
The below procedure is with reference to
figure 14 on page 12.
Mounting of motor
1. Remount the motor (item 8) and make
sure the motor shaft is centred in the
fan casing.
A centring tool is available as an
accessory from Novenco.
2.
Fans with Ø350 hubs and motor sizes
160 or 180:
These motors are mounted
with pins. The pins must be replaced
with new ones when re-mounting the
motors.
3. Insert and tighten the nuts and bolts
(items 7a and 7b) for hub sizes Ø350
and Ø560, or bolts and washers (items
7b and 7c) for hub sizes Ø160.
Notice:
Nuts holding motors
mounted in rear motor
shells are accessed through
the front motor shells.
4. Mount the rotor (item 6) on the motor
shaft with a tool fastened in the
threaded hole of the motor shaft. The
rotor hub must rest against the motor
shaft collar.
5. Use a feeler gauge to check that the
blade tip clearance between the rotor
blade tips and fan casing is the same
throughout the circumference.
6. Adjust the motor position with
reference to step 5.
7. Mount the centre washers and bolt
(item 3).
8.
Fans with hub clips:
Mount the hub
clip, screws and washers (item 4).
9. Mount the hub cap (item 2) and
screws (item 1).
10.Connect the motor cable to the motor
and the power cables in the terminal
box.
11.Reconnect any ducts.
Follow the procedure in section “5. Start
of operation” to start the fan.
6.9 Blade angle adjustment
The rotor blade angles are set in the
factory to deliver the required
performance.
If the fan performance needs to be
changed, it is possible to change the
angles of the blade. This requires
knowledge of the motor load and of the
max. permissible angle with relation to
the motor rating. If the angles are
changed, the rotor has to be re-balanced.
Consult Novenco, before changing the
angles. The blade angle tool for
adjustment, along with instructions for
use, is available from Novenco.
7. Troubleshooting
Fans that operate in the stall
area are more likely to suffer
breakdowns.
Check for the below faults in case of
breakdowns or lack in performance. Call
for service, if problems persist.
200
2
9000
6000
21
4
25000
21000
6
25000
8
225
250
280
4
11000 9000
27
6
16000 13000
8
20000 19000
4
9000
7000
34
6
14000 12000
8
19000 17000
Motor
size
Poles
Lubrication
Grease
amount
[g]
50 Hz
60 Hz
Table 6.
Grease amounts and intervals for
WEG W22 TEFC motors – roller
bearings (Cont.)
Size
Torques [Nm]
Motor bolts (7b)
Centre bolt (3)
M6
9
6
M8
23
12
M10
45
20
M12
78
20
M16
190
25
M20
370
25
Table 7.
Tightening torques
Fan size,
ØD [mm]
Minimum
[mm]
Fan size,
ØD [mm]
Minimum
[mm]
250
0.3
800
0.8
280
0.3
900
0.9
315
0.3
1000
1.0
355
0.4
1120
1.1
400
0.4
1250
1.3
450
0.5
1400
1.4
500
0.5
1600
1.6
560
0.6
1800
1.8
630
0.6
2000
2.0
710
0.7
Table 8.
Blade tip clearance
