Siemens SINAMICS GM150, Operating And Installation Instructions, Page: 181 / 258

The resistors absorb the energy stored in the DC link and limit the current. In the event of false
tripping, the torque surge for the machine, which is still rotating, is limited by the resistors.
WARNING
High voltage
If the short-circuiter is defective, this can significantly increase the discharge time.
High voltages cause death or serious injury if the safety instructions are not observed or if
the equipment is handled improperly.
Never use force to open the doors while the DC-link capacitors are discharging.
Always observe the five safety rules in "Safety information/personnel protection" and in the
drive documentation.
8.4.3.4 Vdc-max closed-loop control
The vdc-max closed-loop control permits (restricted) braking operation of a drive with a diode
supply to the DC link. During braking operation, the machine supplies power back to the DC
link. Due to the configuration, however, a diode supply cannot supply this power back to the
line. The vdc controller controls the supply of power back from the machine to compensate for
losses from the drive system and prevent the DC link voltage from exceeding the maximum
value. This avoids any fault shutdown caused by braking ramps that have been set too short.
The drive stops controlled. The ramp-down times may increase as a result.
Adjustable parameters
Parameter Function Adjustment range
p1240 Vdc_controller configuration 0 ... 3
Factory setting: 1
Setting for the controller configuration for the voltage DC link (vdc controller).
Values:
0: Inhib Vdc ctrl
1: Enable vdc-max controller
The vdc-max controller increases the ramp-down times automatically to keep the DC link voltage within the permissible limits.
Parameter Function Unit
p1242 Vdc_max_controller switch-on level V
Display of the switch-on level of the vdc-max controller.
Operation
8.4 Functions
SINAMICS GM150 6SL3815-2LN41-4AA2
Operating Instructions 04/2017
181