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Maintenance
6.3 Corrective Maintenance
Screwed hub
Two screws should be removed from opposite sides of the connection between the impeller
and the hub in order to attach the pulling device. Do not completely undo the connection
between the impeller and the hub. After separating the impeller and the hub it will be
necessary to rebalance the complete impeller.
Installing
Before mounting the impeller, clean the shaft, feather key and hub and lightly grease them.
The best way to mount the impeller is to use a threaded rod. After fitting the impeller, it is
screwed as far as possible into the motor shaft stub and then mounted with the aid of a nut
and the thrust washer belonging to the impeller. Then secure it with the impeller mounting
screw, thrust washer and a new retaining element.
During installation, always make sure that there is an even gap all around between impeller
and inlet nozzle. [ID 637.01]
6.3.5
Tightening torques for screw and bolt connections
Bolt locking devices
Nuts or bolts that are mounted together with locking, resilient and/or force-distributing
elements must be refitted together with identical, fully functional elements. Always renew
positive-action locking elements.
Threads secured with liquid plastic must be treated accordingly when they are tightened (e.g.
using Loctite 243). Fixing bolts with a clamping length of less than 25 mm must be reinstalled
using suitable retaining elements or soluble locking compound (e.g. Loctite). The clamping
length is taken as the distance between the head of the bolt and the point at which the bolt is
screwed in.
Tightening torques
The bolted connections with metal contact surfaces (end shields, bearing cartridge parts,
terminal box parts bolted onto the stator frame) should be tightened to the following torques,
depending on the thread size.
Table 6-2
A
B
C
The tightening torques in the different rows apply to the following cases:
84
Tightening torques (tolerance ± 10%)
M4
M5
M6
1.2
2.5
4
1.3
2.6
4.5
3
5
8
M8
M10
M12
8
13
20
10
20
34
20
40
70
Siemens AG Operating Instructions 2.02 1FW4
M16
M20
M24
40
-
-
83
160
280
170
340
600
A5E01083943A AB
Nm
Nm
Nm
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