Siemens SINAMICS S120 Equipment Manual page 50

Line-Side Power Components
2.3 Active Interface Modules
Fig. 2-15
Derating factors as a function of site altitude and ambient temperature
If the Active Interface Modules are operated at ambient temperatures of > 40 °C and site
altitudes of > 2000 m, both derating characteristics must be taken into account for the
permissible output power/output current.
A voltage reduction K
accordance with IEC 60664‑1.
Note
If the Active Interface Modules are operated at site altitudes between 2000 m and 4000 m,
the air density and thus also the cooling capacity of the forced-cooled devices decreases.
However, as the ambient temperatures at the site of installation are often lower, a
compensation factor can be calculated for the units in this case. The reduction in current can
be balanced by correction factor K
correction factor K
multiplication result is <1, the rated current must be multiplied by this value to yield the
maximum permissible continuous current.
2-24
Voltage correction factor K
must also be taken into account at site altitudes of > 2000 m in
U
. If the result of multiplying correction factor K
T
is greater than 1, the rated current can be used in the calculation. If the
I
SINAMICS S120 Equipment Manual, Edition 12/2007, 6SL3097-2AM00-0BP4
as a function of site altitude
U
by
T
Chassis Power Units Liquid Cooled