Siemens SINAMICS G120 Operating Instructions Manual page 161

Motor control
The motor closed-loop control ensures that the motor follows the speed setpoint. You can
choose between various control modes.
The inverter has various methods to electrically brake the motor. When electrically braking,
the motor develops a torque, which reduces the speed down to standstill.
Protection of the drive and the driven load
The protection functions prevent damage to the motor, inverter and driven load.
The monitoring of the driven load prevents impermissible operating modes, e.g. dry-running
of a pump.
Increasing the drive availability
The kinetic buffering converts the kinetic energy of the load into electrical energy to buffer short-
term power failures.
The "Flying restart" function permits the fault-free switching on of the motor while it is still
turning.
For active automatic restart, after a power failure, the inverter attempts to automatically restart
the motor and to acknowledge any faults that occur.
Energy saving
For standard induction motors, the efficiency optimization reduces the motor losses in the
partial load range.
If necessary, the main contactor control disconnects the inverter from the power system and
so reduces the inverter losses.
Converter with the CU250S-2 Control Units
Operating Instructions, 04/2018, FW V4.7 SP10, A5E31759476B AG
Overview of the manuals (Page 519)
Motor control (Page 288)
Electrically braking the motor (Page 316)
Overcurrent protection (Page 326)
Inverter protection using temperature monitoring (Page 327)
Motor protection with temperature sensor (Page 330)
Motor protection by calculating the temperature (Page 333)
Motor and inverter protection by limiting the voltage (Page 335)
Monitoring the driven load (Page 337)
Kinetic buffering (Vdc min control) (Page 350)
Flying restart – switching on while the motor is running (Page 344)
Automatic restart (Page 346)
Efficiency optimization (Page 352)
Advanced commissioning
6.1 Overview of the converter functions
159