Siemens SIMOTICS 1FT2104-4AF - Sample Calculation of the Belt Pre-Tension; Radial Eccentricity, Concentricity and Axial Eccentricity

Mechanical properties
3.7 Radial eccentricity, concentricity and axial eccentricity
1FT2 synchronous motors for SINAMICS S120
Configuration Manual, 03/2021, A5E50645584B AA
41
3.6.3 Sample calculation of the belt pre-tension
Note
Carefully comply with the guidelines provided by the belt m
anufacturer
•
Carefully comply with the guidelines provided by the belt manufacture when configuring
the motor for radial forces at the shaft extension.
•
Adjust the belt tension using the appropriate measuring instruments.
FV = 2 • M0 • c / dR
FV ≤ FR, perm
Table 3- 2 Explanation of the formula abbreviations
Formula abbrevia-
tions
Unit Description
FV
N
Belt pre-tension
M0
Nm
Motor static torque
c
–––
Pre-tensioning factor; this factor is an empirical value provided
by 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
FR, perm
N
Permissible radial force
When using other configurations, you must take into account the actual forces generated
from the torque being transferred.
3.7 Radial eccentricity, concentricity and axial eccentricity
The shaft and flange accuracies for the 1FT2 motors are implemented to DIN 42955
(IEC 60072-1) as standard (Normal class).
Table 3- 3 Radial eccentricity tolerance of the shaft to the frame axis (referred to cylindrical shaft ex-
tension)
Motor
Standard (Normal class)
1FT2☐03
0.035 mm
1FT2☐04
0.04 mm
1FT2☐05
1FT2☐06
1FT2☐08
0.05 mm
1FT2☐10