Siemens SINAMICS G120 Operating Instructions Manual page 323

If the measure cannot prevent an inverter thermal overload, then the inverter switches off the
motor with fault F30024.
Overload response for p0290 = 1
The inverter immediately switches off the motor with fault F30024.
Overload response for p0290 = 2
We recommend this setting for drives with square-law torque characteristic, e.g. fans.
The inverter responds in two stages:
1. If you operate the inverter with increased pulse frequency setpoint p1800, then the inverter
reduces its pulse frequency starting at p1800.
In spite of the temporarily reduced pulse frequency, the base load output current remains
unchanged at the value that is assigned to p1800.
Figure 6-48
Once the overload condition has been removed, the inverter increases the pulse frequency
back to the pulse frequency setpoint p1800.
2. If it is not possible to temporarily reduce the pulse frequency, or the risk of thermal overload
cannot be prevented, then stage 2 follows:
– In vector control, the inverter reduces its output current.
– In U/f control, the inverter reduces the speed.
Once the overload condition has been removed, the inverter re-enables the output current
or speed.
If both measures cannot prevent a power unit thermal overload, then the inverter switches off
the motor with fault F30024.
Overload response for p0290 = 3
If you operate the inverter with increased pulse frequency, then the inverter reduces its pulse
frequency starting at the pulse frequency setpoint p1800.
In spite of the temporarily reduced pulse frequency, the maximum output current remains
unchanged at the value that is assigned to the pulse frequency setpoint. Also see p0290 = 2.
Once the overload condition has been removed, the inverter increases the pulse frequency
back to the pulse frequency setpoint p1800.
Converter with the CU230P-2 Control Units
Operating Instructions, 09/2017, FW V4.7 SP9, A5E34257946B AE
Derating characteristic and base load output current for overload
6.27 Inverter protection using temperature monitoring
Advanced commissioning
323