Siemens 1FT7 - Calculating the Belt Pre-Tension; Radial and Axial Forces; Radial Force Loading

Mechanical properties of the motors
3.6 Radial and axial forces
1FT7 Synchronous Motors
64 Configuration Manual, (PFT7S) 01/2009, 6SN1197-0AD13-0BP2
3.6 Radial and axial forces
3.6.1 Calculating the belt pre-tension
F
V
[N] = 2 • M
0
• c / d
R
F
V
≤ F
R, perm
Table 3- 11 Explanation of the formula abbreviations
Formula abbreviations Unit Description
F
V
N Belt pre-tension
M
0
Nm Motor static torque
c ––– Pre-tensioning factor: this factor is an empirical value provided
by the belt manufacturer. It can be assumed to be as follows:
for toothed belts: c = 1.5 to 2.2
for flat belts c = 2.2 to 3.0
d
R
m Effective diameter of the belt pulley
F
R, perm
N Permissible radial force
When using other configurations, the actual forces, generated from the torque being
transferred, must be taken into account.
3.6.2 Radial force loading
Point of application of radial forces F
R
at the shaft end
● for average operating speeds
● for a nominal bearing lifetime of 25,000 h
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Figure 3-4 Force application point at the DE