Siemens SINAMICS G120 - Selecting the V;F Characteristic

Setting functions
8.5 Motor control
Inverter with CU230P-2 Control Units
252 Operating Instructions, 11/2013, FW V4.6.6, A5E02430659B AG
The value of the motor 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 motor voltage as a function of the input voltage is provided in the
technical data, also see Section Technical data, Power Modules (Page 375).
8.5.1.2
Selecting the V/f characteristic
Procedure
Proceed as follows to select a V/f characteristic:
1. Go online.
2. Select the V/f characteristic curve in one of the screen forms "speed controller"
or "V/f control".
1. Go into the menu "PARAMS".
2. As a parameter filter, select "EXPERT".
3. Set p1300 to the appropriate value.
You have selected a V/f characteristic.
Table 8- 20 Linear and parabolic characteristics
Requirement
Application examples
Remark
Characteristic
Parameter
The required
torque is
independent of the
speed
Conveyor belts, roller
conveyors, chain
conveyors, 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
according to the rating plate and have
performed the motor identification after
the basic commissioning.
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