Siemens SINAMICS S120 Equipment Manual page 304

Cabinet design and EMC for components, Blocksize format
9.7 Information on cabinet cooling
Figure 9-4
Caution
The air guidance and arrangement of the cooling equipment must be chosen in such a way
as to prevent condensation from forming.
If necessary, cabinet enclosure heating may have to be installed.
If air conditioners are used, the relative air humidity of the expelled air increases as the air in
the air conditioner cools and may exceed the dew point. If the relative humidity of the air
entering the SINAMICS equipment is over 80% for an extended period of time, the insulation
in the equipment may fail to function properly due to electrochemical reactions (refer to
System Overview). Using air baffle plates, for example, you must ensure that the cold air
expelled from the air conditioner mixes with warm air in the cabinet before it enters the
equipment. This reduces the relative air humidity to uncritical values.
9-20
Examples of cabinet ventilation
Equipment Manual AC Drive
Manual, (GH6), 03/2006 Edition, 6SL3097-2AL00-0BP0