Information About Cabinet Design - Siemens SINAMICS G130 Engineering Manual

Pressure drop as a function of volumetric flow rate for Active Interface Modules in frame size JIL
1.16.8

Information about cabinet design

The liquid-cooled SINAMICS S120 units in Chassis format designed for installation in converter cabinets and the
associated air-cooled system components such as
·
electronic components (Control Units, Terminal Modules, Sensor Modules, etc.),
·
power cables and busbars,
·
line-side switches, contactors, fuses and filters,
·
motor-side reactors and filters
generate power losses in operation. These power losses (which are specified in the technical data in catalog D 21.3
or the relevant operating instructions) must be expelled from the cabinet in order to prevent an excessive temperature
rise inside the cabinet and to allow the units and system components to operate within their permissible temperature
limits. Operation within the permissible temperature limits is essential in order to a) prevent shutdown on faults in
response to overheating and b) to prevent premature failure of components which can occur if they are operating at
excessive temperatures.
Liquid-cooled SINAMICS S120 units in Chassis format transfer almost all of their power losses (i.e. around 95 %)
directly to the coolant via their heat sink, so that only a few percent of the total power losses need to the dissipated to
the air inside the cabinet. Since the air inside the cabinet must also absorb the power losses from electronic
components, power cables, busbars, fuses and possibly other air-cooled system components, however, it is
absolutely essential that the cabinet is cooled adequately. It might therefore be necessary to install additional fans
and air-to-water heat exchangers inside the cabinet dependent on the mounting position of the liquid-cooled Chassis
units (vertical or horizontal), the components to be cooled and the degree of protection of the cabinet itself.
Cabinet cooling requirements depending on the mounting position of the liquid-cooled Chassis units (vertical or
horizontal) and the degree of protection of the cabinet are discussed in more detail below.
Vertical installation inside a cabinet
Liquid-cooled SINAMICS S120 units are suitable for installation in a vertical position inside a cabinet with a minimum
width of 400 mm.
Depending on the degree of protection of the cabinet, different measures must be taken to ensure that the heat
losses in the Chassis unit and therefore inside the cabinet are effectively dissipated.
The Chassis units can be installed without additional fans in cabinets with a degree of protection of ≤ IP21. In this
case the cabinet is cooled by free convection through the perforated top cover.
With degrees of protection of > IP21, a fan installed at the top of the cabinet door (or mounted in the hood of the
converter cabinet above the Chassis unit) must provide forced cooling in order to prevent the accumulation of heat
inside the cabinet. The table below states the minimum required volumetric flow rates dV/dt as well as the average
Fundamental Principles and System Description
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Engineering Information
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