Siemens SINAMICS S120 Configuration Manual page 42

Electrical data
4.2 Voltage limiting characteristics
The characteristic curve is plotted for each armature circuit in a separate data sheet.
The torque-speed diagrams for different converter output voltages are then assigned to each
data sheet.
Note
The voltage limit characteristic of a motor with 6000 RPM rated speed lies far above that
of the same motor type with 2000 RPM. However, for the same torque, this motor requires
a significantly higher current.
For this reason, you should select the rated speed such that it does not lie too far above
the maximum speed required for the application.
The size (rating) of the converter module (output current) can be minimized in this fashion
Offset of the voltage limit characteristic
Notice
The offset of the voltage limiting characteristic applies only in the case of approximately
linear limiting characteristic curves, e.g. for 1FK7 motors.
In order to identify the limits of the motor for a converter output voltage (U
380 V, 425 V, or 460 V, the relevant voltage limiting characteristic curve must be shifted
(offset) for the particular new output voltage (U
The degree of offset is obtained as follows:
For an output voltage of U
V
V
Notice
It is only possible to shift the voltage limiting characteristic, if the condition
U
mot, new
The induced voltage U
U
iN
42
U = new converter output voltage
mot, new
U = drive converter output voltage from the characteristic curve for 380 V,
mot
425 V, or 460 V
> U is fulfilled.
iN
is specified on the motor rating plate.
iN
= k ∙ n / 1000
E N
mot new
, an offset is obtained along the X axis (speed) by a factor of:
mot, new
Configuration Manual, (PFK7S), Edition 12.2006, 6SN1197-0AD16-0BP1
mot
).
Synchronous Motors 1FK7
) other than