Configuration Manual Synchronous Motors 1FT6 - Siemens ...

Technical Data and Speed-Torque Diagrams
3.2 Cantilever force diagrams
3.2 Cantilever force diagrams
Cantilever force stressing
Point of application of cantilever forces FQ at the shaft end
• for average operating speeds
• for a nominal bearing lifetime of 20.000 h
Figure 3-106 Force application point at the drive shaft end
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Dimension x: Distance between the point of application of force FQ and the shaft shoulder in
mm.
Dimension l: Length of the shaft end in mm.
Calculating the belt pre-tension force FR
FR [N] = 2 • M0 • c / dR FR ≤ FQperm
Table 3-64 Explanation of the formula abbreviations
Formula abbreviations Units Description
FR
N Belt pre-tension
M0 Nm Motor stall torque
c ––– Pre-tensioning factor; the pre-tensioning factor is an
empirical value from the belt manufacturer.
It can be assumed as follows:
for toothed belts: c = 1.5 to 2.2
for flat belts c = 2.2 to 3.0
dR m Effective diameter of the belt pulley
When using other configurations, the actual forces, generated from the torque being
transferred, must be taken into account.
1FT6 synchronous motors
3-128 Configuration Manual, (PFT6), Edition 12.2004, 6SN1197-0AD12-0BP0