Mechanical properties of the motors 
  3.6 Radial and axial forces 
1FT7 Synchronous Motors 
Configuration Manual, (PFT7S) 01/2009, 6SN1197-0AD13-0BP2 
67 
Radial force, 1FT7 Compact, AH 100 
[>PP@
)
5'(
>1@
Q USP
Q USP
Q USP
Q USP
Q USP
 
Figure 3-9  Radial force F
R
 at a distance x from the shaft shoulder for a statistical bearing lifetime of 
25,000 h 
3.6.4  Axial force stressing 
When using, for example, helical toothed wheels as the drive element, in addition to the 
radial force, there is also an axial force on the motor bearings. For axial forces, the spring-
loading of the bearings can be overcome so that the rotor is displaced corresponding to the 
axial bearing play present.  
 
Shaft height  Displacement 
36 and 48  Approx. 0.2 mm 
63 to 100  Approx. 0.35 mm 
An axial force as large as the spring-loading is not permitted (100 ... 500 N). Premature 
failure is the result when the bearing is not pre-tensioned. 
Calculating the permissible axial force: F
A
 = F
R
 • 0.35  
 
WARNING 
 
Motors with integrated holding brake cannot be subject to axial forces!