Axial Force - Siemens SINAMICS S120 Configuration Manual

Mechanical properties of the motors

3.5 Axial force

3.5 Axial force
The axial force acting on the locating bearings comprises an external axial force (e.g.
gearbox with helical gearing, machining forces through the tool), a bearing pre-load force
and possibly the force due to the weight of the rotor when the motor is vertically mounted.
This results in a maximum axial force that is a function of the direction.
When helical toothed wheels, for example, are used as the drive element, in addition to the
radial force there is also an axial force on the motor bearings. For axial forces in the direction
of the motor, the spring-loading of the bearing can be overcome. This must be prevented, as
under certain circumstances, the bearing pre-loading is cancelled which means that the
bearing lifetime could be reduced.
Calculating the permissible axial force F
The permissible axial force F
Table 3- 9 Calculating the permissible axial force
Horizontal arrangement
F Permissible axial force in operation
AZ
F Permissible axial force as a function of the average speed
A
F Force due to spring-loaded bearing
C
F Force due to weight of rotor
L
56
AZ
in operation depends on the motor mounting position.
AZ
Shaft end facing downwards
Configuration Manual, (APH4S), 08/2008, 6SN1197-0AD64-0BP1
Shaft end facing upwards
1PH4 Induction Motors