Siemens SINAMICS G120C USS/MB Operating Instructions Manual page 262

Advanced commissioning
6.19 Motor control
The value of the output voltage at the rated motor frequency also depends on the following
variables:
● Ratio between the inverter size and the motor size
● Line voltage
● Line impedance
● Actual motor torque
The maximum possible output voltage as a function of the input voltage is provided in the
technical data.
Table 6-48 Linear and parabolic characteristics
Requirement Application examples
The required tor‐ Conveyor belts, roller
que is independent conveyors, chain con‐
of the speed veyors, eccentric worm
pumps, compressors,
extruders, centrifuges,
agitators, mixers
The required tor‐ Centrifugal pumps, ra‐
que increases with dial fans, axial fans
the speed
Table 6-49 Characteristics for special applications
Requirement
Applications with a low dy‐
namic response and con‐
stant speed
The inverter must maintain
the motor speed constant for
the longest possible time.
Freely adjustable U/f charac‐
teristic
U/f characteristic with inde‐
pendent voltage setpoint
Additional information on U/f characteristics can be found in the parameter list and in the
function diagrams 6300 ff of the List Manual.
262
Technical data (Page 401)
Remark
-
The inverter equalizes the voltage drops across
the stator resistance. Recommended for motors
less than 7.5 kW.
Precondition: You have set the motor data accord‐
ing to the rating plate and have performed the mo‐
tor identification after quick commissioning.
Lower losses in the motor and inverter than for a
linear characteristic.
Application Remark
examples
Centrifugal If the speed setpoint is reached, and remains
pumps, radial unchanged for 5 seconds, then the inverter re‐
fans, axial duces is output voltage.
fans
As a consequence, the ECO mode saves en‐
ergy with respect to the parabolic characteris‐
tic.
Drives in the When reaching the maximum current limit, the
textile sector inverter only reduces the output voltage, but
not the frequency.
- -
- The interrelationship between the frequency
and voltage is not calculated in the inverter,
but is specified by the user.
Operating Instructions, 09/2017, FW V4.7 SP9, A5E34263257B AF
Characteris‐ Parameter
tic
Linear p1300 = 0
Linear with p1300 = 1
Flux Cur‐
rent Control
(FCC)
Parabolic p1300 = 2
Characteristic Parameter
ECO mode p1300 = 4
or
p1300 = 7
Precise fre‐ p1300 = 5
quency char‐ or
acteristic p1300 = 6
Adjustable p1300 = 3
characteristic
Independent p1300 = 19
voltage set‐
point
SINAMICS G120C converter