Advanced commissioning
7.11 Motor control
SIMATIC ET 200pro FC-2 converter
154
Operating Instructions, 04/2018, FW V4.7 SP10, A5E34257324B AF
Requirement
Application
examples
Remark
Characteristic Parameter
Freely adjustable U/f char-
acteristic
-
-
Adjustable
characteristic
p1300 = 3
U/f characteristic with inde-
pendent voltage setpoint
-
The interrelationship between the frequency
and voltage is not calculated in the inverter,
but is specified by the user.
Independent
voltage set-
point
p1300 = 19
Additional information on U/f characteristics can be found in the parameter list and in the
function diagrams 6300 ff of the List Manual.
7.11.1.3
Optimizing motor starting
After selection of the U/f characteristic, no further settings are required in most applications.
In the following circumstances, the motor cannot accelerate to its speed setpoint after it has
been switched on:
●
Load moment of inertia too high
●
Load torque too large
●
Ramp-up time p1120 too short
To improve the starting behavior of the motor, a voltage boost can be set for the U/f
characteristic at low speeds.
Setting the voltage boost for U/f control
The inverter boosts the voltage corresponding to the starting currents p1310 … p1312.
Figure 7-27 The resulting voltage boost using a linear characteristic as example