Siemens SINAMICS G120D Operating Instructions Manual page 52

Installation
4.2 Electrical Installation
Installation with power bus
For installations with several inverters, the inverters are normally supplied from a 400 V
power bus using T distributors.
Figure 4-14
The following options are available for the 24 V supply of the inverter:
1. A T distributor with integrated power supply unit supplies the 24 V.
Advantage: Low installation costs.
2. An external power supply unit supplies the 24 V.
Advantage: You can disconnect the 400 V without interrupting the 24 V supply and
therefore without interrupting the fieldbus communication of the inverter.
The inverter can conduct a maximum current of 8 A through its 24 V connector.
Protection of the 400V cable
Cable protection depends on the following conditions:
● Cable routing type.
● Limit values of the cables and system components, e.g. the T distributor.
● Country-specific guidelines.
If no other restrictions apply, then select the power bus fusing according to the following
table.
Table 4- 12
Rated power of the smallest inverter
connected to the power bus
0.75 kW
1.5 kW
3 kW
4 kW
5.5 kW
7.5 kW
1
52
Inverter supplied via a power bus
Maximum fusing of the power bus
The values do not apply to installations conforming to UL specifications.
Maximum permissible fusing
32 A 3NA3812
32 A 3NA3812
32 A 3NA3812
35 A 3NA3814
45 A 3NA3820
63 A 3NA3822
Operating Instructions, 04/2014, FW V4.7, A5E34262100B AA
Circuit-breaker
1
3RV1031-4FA10
3RV1031-4FA10
3RV1031-4FA10
3RV1031-4FA10
3RV1031-4HA10
3RV1041-4KA10
Converter with control units CU240D-2