Advanced commissioning
7.11 Motor control
SIMATIC ET 200pro FC-2 converter
Operating Instructions, 04/2018, FW V4.7 SP10, A5E34257324B AF
153
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.
Technical data (Page 245)
7.11.1.2
Selecting the U/f characteristic
Table 7- 27 Linear and parabolic characteristics
Requirement
Application examples
Remark
Characteris-
tic
Parameter
The required
torque is inde-
pendent of the
speed
Conveyor belts, roller
conveyors, chain con-
veyors, eccentric worm
pumps, compressors,
extruders, centrifuges,
agitators, mixers
-
Linear
p1300 = 0
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 ac-
cording to the rating plate and have performed
the motor identification after quick commission-
ing.
Linear with
Flux Current
Control
(FCC)
p1300 = 1
The required
torque increases
with the speed
Centrifugal pumps,
radial fans, axial fans
Lower losses in the motor and inverter than for a
linear characteristic.
Parabolic
p1300 = 2
Table 7- 28 Characteristics for special applications
Requirement
Application
examples
Remark
Characteristic Parameter
Applications with a low
dynamic response and
constant speed
Centrifugal
pumps, radial
fans, axial
fans
If the speed setpoint is reached, and remains
unchanged for 5 seconds, then the inverter
reduces is output voltage.
As a consequence, the ECO mode saves
energy with respect to the parabolic charac-
teristic.
ECO mode
p1300 = 4
or
p1300 = 7
The inverter must maintain
the motor speed constant
for the longest possible
time.
Drives in the
textile sector
When reaching the maximum current limit,
the inverter only reduces the output voltage,
but not the frequency.
Precise fre-
quency char-
acteristic
p1300 = 5
or
p1300 = 6