Derating As A Function Of The Installation Altitude And Ambient Temperature - Siemens SINAMICS S120 Combi User Manual

1.3 Derating as a function of the installation altitude and ambient
temperature
The S120 Combi Power Modules and Motor Modules Booksize Compact are designed for
operation at an ambient temperature of 40 °C, installation altitudes up to 1000 m above sea
level and the relevant specified pulse frequency.
The air pressure and therefore air density drop at altitudes above sea level. At these
altitudes, the same quantity of air does not have the same cooling effect and the air gap
between two electrical conductors can only insulate a lower voltage. Typical values for air
pressure are summarized in the table below:
Table 1- 4 Air pressure for various installation altitudes
Installation altitude above sea level
in [m]
Air pressure in mbar [kPa]
The output current must be reduced if the modules are operated at ambient temperatures
above 40 °C (see derating characteristics for the individual modules). Ambient temperatures
above 55 °C are not permissible.
The air gaps inside the devices can insulate surge voltages of surge voltage category III in
accordance with EN 60664-1 up to an installation altitude of 2000 m. At installation altitudes
above 2000 m, the Power Modules must be connected using an isolating transformer. The
isolating transformer reduces surge voltages of surge voltage category III in power supplies
to surge voltages of surge category II at the power terminals of the Power Modules and
thereby conforms to the permissible voltage values for air gaps inside the unit. The design of
the secondary line supply system must be as follows:
● TN system with grounded star point (no grounded outer conductor)
● IT system
A reduction of the line supply voltage phase-phase is not necessary.
SINAMICS S120 Combi
Manual, Edition 07/2012, 6SL3097-4AV00-0BP3

1.3 Derating as a function of the installation altitude and ambient temperature

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System overview
5000
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