Siemens SINAMICS G120D - Selecting the U;F Characteristic; Optimizing with a High Break Loose Torque and Brief Overload

Setting functions
8.5 Motor control
Converter with control units CU250D-2
138 Operating Instructions, 04/2014, FW V4.7, A5E34261542B AA
8.5.1.2
Selecting the U/f characteristic
Table 8- 15 U/f 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 with a low
power rating.
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
Additional information on U/f characteristics can be found in the parameter list and in the
function diagrams 6300 ff of the List Manual.
8.5.1.3
Optimizing with a high break loose torque and brief overload
Setting the voltage boost for U/f control
The voltage boost acts on every U/f
characteristic. The adjacent diagram
shows the voltage boost using a linear
character
istic as example.
Procedure
Proceed as follows to set the voltage boost:
Only increase the voltage boost in small steps. Excessively high values in p1310 ... p1312
can cause the motor to overheat and switch off (trip) the inverter due to overcurrent.
1. Power-up the motor with an average speed.
2. Reduce the speed to just a few revolutions per minute.
3. Check whether the motor rotates smoothly.
4. If the motor does not rotate smoothly, or even remains stationary, increase the voltage
boost p1310 until you are satisfied with the motor behavior.