Fundamental Principles and System Description
Engineering Information
SINAMICS Engineering Manual – November 2015
Ó Siemens AG
215/528
Installation altitudes over 2000 m and up to 4000 m above sea level
Liquid-cooled SINAMICS S120 units in Chassis format are rated for an installation altitude of up to 2000 m above sea
level and a coolant inlet and ambient temperature of 45 °C. If liquid-cooled SINAMICS S120 units in Chassis format
are operated at an installation altitude higher than 2000 m above sea level, it must be taken into account that air
pressure and thus air density decrease in proportion to the increase in altitude. As a result of the drop in air density
the cooling effect and the insulation strength of the air are reduced. Under these conditions, it is therefore necessary
to reduce the permissible ambient temperature and the input voltage.
The following charts indicate the permissible ambient temperature and input voltage as a function of the installation
altitude for altitudes of over 2000 m up to 4000 m.
Ambient temperature derating as a function of altitude Input voltage derating as a function of altitude
Pressure drop as a function of volumetric flow for water (H2O) as the coolant
The operating pressure in the cooling circuit must be determined according to the flow conditions in the inflow and
return flow lines. The coolant flow rate dV/dt (l/min) required for individual units can be found in the technical data
specified in catalog D 21.3. The units are designed for a pressure drop of 70 kPa (0.7 bar) (referred to water as the
coolant (H2O)) which is implemented by means of an baffle plate, i.e. with a pressure drop of 70 kPa (0.7 bar), the
coolant flow rate specified in the technical data of catalog D 21.3 is reached if water (H2O) is used as a coolant. The
following diagram specifies the pressure drop for water (H2O) as the coolant as a function of the coolant flow rate
dV/dt for liquid-cooled SINAMICS units in the different frame sizes.
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