Siemens SINAMICS S120 Combi Equipment Manual page 248

Cabinet design and EMC
12.6 24 V DC supply
Note
A regulated DC power supply is required to operate motors with a built-in holding brake. The
power supply is realized via the internal 24 V busbars. The voltage tolerances of the motor
holding brakes (24 V ±10%) and the voltage drops of the connecting cables must be taken
into account.
The DC power supply should be set to 26 V. The Control Supply Module supplies 26 V. This
ensures that the supply voltage for the brake remains within the permissible range when the
following conditions are fulfilled:
• Use of Siemens three-phase motors
• Use of Siemens MOTION-CONNECT power cables
• Motor cable lengths, max. 50 m
NOTICE
If other consumers are connected to the power supply, connected inductance devices
(contactors, relays) must be fitted with suitable overvoltage protection circuits.
248
SINAMICS S120 Combi
Manual, Edition 05.2010, 6SL3097-4AV00-0BP0