Siemens SINAMICS S120 - Page 67

Configuration
5.3 Dimensioning
Synchronous Motors 1FK7
Configuration Manual, (PFK7S), Edition 12.2006, 6SN1197-0AD16-0BP1
67
J
M
Motor moment of inertia
J
G
Gearbox moment of inertia
J
load
Load moment of inertia
n
Load
Load speed
i Gear ratio
η
G
Gearbox efficiency
M
load
Load torque
M
R
Frictional torque
T Cycle time, clock cycle time
A; E Initial value, final value in time slice Δ
t
i
t
e
ON period
∆t
i
Time interval
The RMS torque M
rms
must lie below the S1 curve.
The maximum torque M
max
is produced during the acceleration operation.
For synchronous motors, M
max
must lie below the voltage limiting characteristic curve.
For induction motors, M
max
must lie below the stability limit.
In summary, the motor is selected as follows:
Figure 5-9 Selecting motors depending on the load duty cycle (example)