Siemens SINAMICS G130 Operating Instructions Manual page 30

Cabinet air conditioning
5.2 Ventilation
Figure 5-2
Devices must not be operated in an "air short-circuit", since this can damage equipment or
cause it to fail.
The fan suction causes negative pressure to build up at the ventilation openings in the
cabinet doors. The pressure is dependent on the volume flow rate and the hydraulic cross-
section of the openings.
The air, which blows out of the top of the device, accumulates under the top cover/hood,
resulting in overpressure.
The difference between the overpressure at the top of the cabinet and the negative pressure
at the bottom creates a flow of air (air short-circuit). This can vary in strength depending on
the cross-section of the door and cover openings, as well as the volume flow rate of the air.
Due to the flow of air within the cabinet, the device fan draws in pre-heated air. This heats up
the components considerably and the ventilator does not function effectively.
30
Air guidance for Power Module, frame size HX, JX
Cabinet design and EMC
Operating Instructions, 07/2016, A5E00427629A