Siemens SIMOTICS S-1FL6 Operating Instructions Manual page 97

Note
It is the Isolated digital output power supply. Select a proper power supply based on the
1)
relay type. When you use the 24 VDC power supply, it can be also the controller power
supply.
The motor brake can be controlled not only by the brake control signal from the SINAMICS
2)
V90 PN servo drive but also by external emergency stop.
Never use the same power supply for the brake (24 VDC) and for the brake control signal
3)
(P24 V).
Install a surge absorber or a diode as shown above to suppress the surge voltage or surge
4)
current generated by an ON/OFF action of the relay (RY). When you use a diode, the time
period from brake release to brake engagement is longer than the case when you use a
surge absorber.
For the 400 V variant servo drive
Surge absorber and diode used for the power supply of the brake
Note
All the following data on a surge absorber or diode is provided based on the low inertia
motors with a rated power of 2 kW; however the data is also applicable to the low inertia
motors of other power ranges.
Consider the following current-time and voltage-time characteristics when making a decision
to use a surge absorber or a diode to suppress the surge voltage or surge current:
SINAMICS V90, SIMOTICS S-1FL6
Operating Instructions, 09/2016, A5E37208830-002
Connecting
4.7 Motor holding brake
97