Dynamic Braking - Siemens SINAMICS G120 Operating Instructions Manual

Advanced commissioning
6.25 Electrically braking the motor
6.25.3

Dynamic braking

Typical applications for dynamic braking require continuous braking and acceleration
operations or frequent changes of the motor direction of rotation:
● Horizontal conveyors
● Vertical and inclined conveyors
● Hoisting gear
Principle of operation
The DC link voltage increases as soon as the motor supplies regenerative power to the inverter
when braking. The regenerative power means that the DC link voltage in the inverter increases.
Depending on the DC link voltage, the inverter outputs the regenerative power to the braking
resistor through the braking chopper. The braking resistor converts the regenerative power
into heat, therefore preventing DC link voltages > Vdc_max.
Figure 6-47
318
Simplified representation of dynamic braking with respect to time
Converter with the CU230P-2 Control Units
Operating Instructions, 09/2017, FW V4.7 SP9, A5E34257946B AE