The Altivar 71 Drive Braking IGBT operates when the value of DC Bus Voltage is higher than the DC Bus Threshold Voltage OBR. When the value of the DC Bus Voltage is lower than the threshold voltage (Unom_max + 10%), the Braking IGBT/Transistor is switched off.
The Voltage Threshold Values for a Drive working on 220VAC or 415VAC, 3Phase is provided in the attachment.
Note:
OBR is the threshold point where the Braking Transistor switches ON and Unom_max + 10% is the threshold point where the Braking Transistor switches OFF.