Siemens SINAMICS G150 Operating Instructions Manual page 649

Table 12- 5 Current derating as a function of the ambient temperature (inlet air temperature at the air inlet of the cabinet
unit) and installation altitude for cabinet units with degree of protection IP54
Installation altitude
above sea level in m
0 ... 2000
... 2500
... 3000
... 3500
... 4000
... 4500
... 5000
Using an isolating transformer to reduce transient overvoltages according to IEC 61800-5-1
This drops overvoltage category III to overvoltage category II, thereby reducing the
requirements for insulation capacity of the air. Additional voltage derating (reduction of the
input voltage) is not required if the following framework conditions are observed:
● The isolating transformer must be fed from a low-voltage or medium-voltage network and
must not be power directly from a high-voltage supply system.
● The isolating transformer may be connected to one or more cabinet units.
● The cables between the isolating transformer and the cabinet unit(s) must be routed in
such a manner as to rule out direct lightning strike, i.e. overland lines must not be used.
● The following types of system are permissible:
– TN systems with grounded star point (no grounded outer conductor).
– IT systems (operation with a ground fault must be restricted to the shorted possible
Converter cabinet units
Operating Instructions, 07/2016, A5E03347396A
at an ambient temperature (air inlet temperature) of
20° C 25° C
100 % 100 %
100 % 100 %
100 % 100 %
100 % 100 %
100 % 96.3 %
97.5 % 92.1 %
93.0 %
time).
Current derating factor
30° C 35° C
100 % 100 %
100 % 96.3 %
98.7 % 92.5 %
94.7 %
90.7 %
Technical specifications
12.2 General data
40° C 45° C
93.3 % 86.7 %
89.8 %
50° C
80.0 %
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