Siemens SIMOTICS S-1FK2 Series Configuration Manual page 57

Free duty cycle
A free duty cycle defines the curve of the motor speed and the torque over time.
n
M
t
Figure 5-4
Procedure
Determine the required motor torque as follows:
1. Define a load torque for each time slice. Also take the average load moment of inertia and
motor moment of inertia into account for acceleration operations. If required, take a
frictional torque into account that opposes the direction of motion.
2. With mounted gearbox:
Determine the load torque and the acceleration torque that must be supplied by the
motor. Take the gear ratio and gear efficiency into account.
Note
A higher gear ratio increases positioning accuracy in terms of encoder resolution. For any
given encoder resolution, as the gear ratio increases, so does the resolution of the
machine position to be detected.
1FK2 synchronous motors for SINAMICS S120
Configuration Manual, 06/2019, A5E46927724B AB
Speed T
Torque Δt
i
Time
Example of free duty cycle
Cycle time
Time interval
Configuration
5.2 Configuring procedure
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