Siemens SINAMICS S150 NEMA, Operating Instructions Manual, Page: 139 / 862

Electrical installation
4.9 Additional connections
Enclosed Drives
Operating Instructions, 12/2018, A5E36652151A
137
4.9.11.3 Diagnosis and duty cycles
Diagnosis
If the thermostat is opened due to a thermal overload on the braking resistor, fault F7861
("External Fault 2") is triggered and the drive is switched off with OFF2.
If the brake chopper triggers a fault, fault F7862 "External fault 3" is triggered in the drive.
You can acknowledge malfunctions in the braking unit by pressing the "Acknowledge" button
on the operator panel when the DC link voltage is present).
Duty cycles
Figure 4-25 Duty cycles for the braking resistors
4.9.11.4 Threshold switch
The response threshold at which the braking unit is activated and the DC link voltage
generated during braking is specified in the following table.
Note
Activate braking operation only in the event of a power failure
Since the braking energy is normally supplied back to the line and the braking chopper is
only to be activated in the event of a power failure, the default threshold value setting should
be retained rather than reduced.