14108242 Installation, operation and maintenance manual – Squirrel cage motor – WGM20 Line l 45
8.3
AIR-GAP MEASUREMENT
After disassembling and assembling the motor, it is
necessary to measure the air gap in order to check the
concentricity between rotor and stator.
The difference between the air-gap measured in two
points diametrically opposed must be less than 10% of
the average air gap.
8.4
TIGHTENING TORQUE
Table 8.1 and Table 8.2 shows the tightening torques of
the screws recommended for assembling the motor.
Table 8.1: Screw tightening torque for metal/metal parts
Material /
Resistance
class
Carbon Steel /
8.8 or above
Stainless steel /
A2 – 70 or above
% Yield
Strength
60%
70%
Lubricant
Dry
Molycote
1000
Dry
Molycote
1000
Diam
Pitch
(mm)
Screws tightening torque (Nm)
M3
0,5
1,2
0,8
1
0,69
M4
0,7
2,7
1,8
2,4
1,6
M5
0,8
5,4
3,6
4,8
3,2
M6
1
9,3
6,3
8,2
5,5
M8
1,25
22,4
15
20
13
M10
1,5
44
30
39
26
M12
1,75
77
52
67
45
M14
2
123
82
107
72
M16
2
188
126
165
110
M18
2,5
263
176
230
154
M20
2,5
368
246
322
215
M22
2,5
500
332
437
290
M24
3
637
425
557
372
M27
3
926
615
810
538
M30
3,5
1260
838
1102
734
M33
3,5
1704
1130
1490
990
M36
4
2195
1459
1920
1277
M42
4,5
3507
2328
3070
2037
M48
5
5258
3488
4600
3052
Table 8.2: Screw tightening torque for metal/isolated parts
Material /
Resistance
class
Carbon Steel /
8.8 or above
Stainless steel /
A2 – 70 or above
% Yield
Strength
33%
33%
Lubricant
Dry
Molycote
1000
Dry
Molycote
1000
Diam
Pitch
(mm)
Screws tightening torque (Nm)
M3
0,5
0,6
0,5
0,48
0,32
M4
0,7
1,5
1
1,1
0,76
M5
0,8
3
2
2,2
1,5
M6
1
5,2
3,4
3,8
2,6
M8
1,25
12,3
8,3
9,2
6,2
M10
1,5
24
16
18,2
12,2
M12
1,75
42
28
32
21
M14
2
68
45
51
34
M16
2
104
69
78
52
M18
2,5
145
98
108
72
M20
2,5
202
135
152
101
M22
2,5
274
183
206
137
M24
3
350
233
263
175
M27
3
510
338
382
254
M30
3,5
693
461
520
346
M33
3,5
937
622
703
466
M36
4
1207
802
905
602
M42
4,5
1929
1280
1447
960
M48
5
2892
1918
2170
1440
NOTE
The resistance class is normally indicated on
the head of the hex bolts.
8.5
SPARE PARTS
WEG recommends that the spare parts required for the
maintenance procedures recommended in the item 9
Maintenance Plan, be kept in stock, as follows:
8.5.1
Necessary spare parts
Table 8.3: Necessary spare parts
DE bearing temperature sensor
NDE bearing temperature sensor
Space heater
Grounding brush
Bearing lubricant
DE bearing
NDE bearing
Cylindrical pressure spring for DE bearing
Cylindrical pressure spring for NDE bearing
Set of seal rings for DE cooling head
Set of seal rings for NDE cooling head
Encoder (if applicable)
The availability of the necessary spare parts is important to
reduce motor downtime due to need replacing
components.
8.5.2
Optional spare parts
The following spare parts are optional and may be
requested to meet any replacement needs.
Table 8.4: Optional spare parts
Vibration sensor for DE bearing (if applicable)
Vibration sensor for NDE bearing (if applicable)
Vibration signal converter for DE bearing (if applicable)
Vibration signal converter for DE bearing (if applicable)
Water temperature sensor (if applicable)
Set of water leakage sensor (if applicable)
Repeater relay for water leak sensor (if applicable)
Water regulating valve (if applicable)
Internal bearing cap for DE bearing
Internal bearing cap for NDE bearing
External bearing cap for DE bearing
External bearing cap for NDE bearing
Grease valve for DE bearing
Grease valve for NDE bearing
Ring with labyrinth for DE bearing
Ring with labyrinth for NDE bearing
Protective ring for DE bearing
Protective ring for NDE bearing
NOTES
When ordering spare parts, inform the motor
model and serial number, according to the
motor nameplate.
The spare parts must be stored in clean, dry,
well-ventilated environments and, if possible,
at constant temperature.
