Siemens SINAMICS S120 Equipment Manual page 440

Cabinet Design and EMC Booksize
8.3 24 V DC supply voltage
Table 8-8 MCBs by conductor cross-section and temperature
Conductor cross-section
1.5 mm
2
2.5 mm
2
4 mm
2
6 mm
2
24 V busbar
The trip characteristic of the MCBs must be selected to match the loads to be protected and
the max. current provided by the power supply unit in the event of a short-circuit.
Example: Calculating 24 V DC current requirements
Table 8-9 Example of 24 V DC current requirements
Component
CU320
8 digital outputs
Active Line Module 36 kW
Motor Module 18 A
Motor Module 30 A
Encoders
Brake
Total:
440
Max. value up to 40 °C
10 A
16 A
25 A
32 A
20 A
Number
1
8
1
2
3
5
5
Max. value up to 55 °C
6 A
10 A
16 A
20 A
20 A
Current consumption
[A]
0.8
0.1
1.5
0.85
0.9
0.25
1.1
Equipment Manual, (GH2), 07/2007, 6SL3097-2AC00-0BP5
Total current consumption
[A]
0.8
0.8
1.5
1.7
2.7
1.25
5.5
14.25
Booksize Power Units