Selecting The U/F Characteristic - Siemens SINAMICS G120D Operating Instructions Manual

8.5.1.2

Selecting the U/f characteristic

Table 8- 16 Linear and parabolic characteristics
Requirement Application examples
The required Conveyor belts, roller
torque is conveyors, chain
independent of the conveyors, eccentric
speed worm pumps,
compressors,
extruders, centrifuges,
agitators, mixers
The required Centrifugal pumps,
torque increases radial fans, axial fans
with the speed
Table 8- 17 Characteristics for special applications
Requirement Application examples
Applications with a Centrifugal pumps,
low dynamic radial fans, axial fans
response and
constant speed
The inverter must Drives in the textile
keep the motor sector
speed constant
under all
circumstances.
Freely adjustable -
U/f characteristic
U/f characteristic -
with independent
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.
Converter with control units CU240D-2
Operating Instructions, 04/2014, FW V4.7, A5E34262100B AA
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
according to the rating plate and have
performed the motor identification after
the basic commissioning.
Lower losses in the motor and inverter
than for a linear characteristic.
Remark
The ECO mode results in additional
energy saving when compared to the
parabolic characteristic.
If the speed setpoint is reached and
remains unchanged for 5 seconds, the
inverter again reduces its output voltage.
When the maximum current limit is
reached, the inverter only reduces the
stator voltage but not the speed.
-
The interrelationship between the
frequency and voltage is not calculated in
the inverter, but is specified by the user.
Setting functions
8.5 Motor control
Characteristic Parameter
Linear p1300 = 0
Linear with Flux p1300 = 1
Current Control
(FCC)
Parabolic p1300 = 2
Characteristic Parameter
ECO mode p1300 = 4
or
p1300 = 7
Precise p1300 = 5
frequency or
characteristic p1300 = 6
Adjustable p1300 = 3
characteristic
Independent p1300 = 19
voltage setpoint
133