Siemens SINAMICS V90 Operating Instructions Manual page 116

Connecting
4.7 Motor holding brake
Example 2:
Note
It is the isolated digital output power supply. Select a proper power supply based on the
1)
relay type (see below for the recommended relay). 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.
Make sure that you use different power supplies for the brake (24 VDC) and for the brake
3)
control signal (P24 V) separately to avoid electro-magnetic interference to electronic
components.
Install a varistor as shown above to suppress the surge voltage or surge current generated
4)
by an ON/OFF action of the relay (RY).
Varistor (V) used for the power supply of the brake
Note
All the following data on a varistor 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.
116
SINAMICS V90, SIMOTICS S-1FL6
Operating Instructions, 04/2017, A5E37208830-003