Siemens SIMOTICS T-1FW3 Configuration Manual page 159

Figure 6-1
The permissible speed range has been limited to n
Torque limit when operating on a SINAMICS S120 without field weakening
It is possible to deactivate the field weakening function with the SINAMICS S120 drive
system. This therefore reduces the operating range that is available.
The shape of the voltage limiting characteristic is determined by the winding version and the
magnitude of the converter output voltage.
The voltage induced in the motor winding increases as the speed increases. The difference
between the DC link voltage of the converter and the induced motor voltage can be used to
apply the current.
For converters without field weakening option, this limits the magnitude of the current that
can be impressed. This causes the torque to drop off quickly at high speeds. All operating
points that can be achieved with the motor lie to the left of the voltage limiting characteristic
that is shown in the diagram.
1FW3 complete torque motors
Configuration Manual, 08/2020, A5E46027705B AA
Torque characteristic of a synchronous motor operating on a SINAMICS drive system
with field weakening (example characteristic)
Technical data and characteristics
.
max Inv
6.1 Explanations
157