How to balance shielding and heat dissipation in the air vents of frequency converters

When designing ventilation openings for inverter cabinets, both electromagnetic shielding and heat dissipation efficiency must be considered. Common solutions include waveguide arrays or honeycomb panels. Waveguide arrays consist of numerous densely arranged hexagonal or circular holes, each acting as a cutoff waveguide to attenuate electromagnetic waves above its cutoff frequency. During design, the size of each hole is determined by the highest frequency to be shielded; smaller hole diameters result in higher cutoff frequencies and better shielding effectiveness, but also greater ventilation resistance. Honeycomb panels, composed of continuous hexagonal holes, offer superior shielding effectiveness compared to circular hole arrays of the same diameter.

Another option is to cover larger ventilation openings with wire mesh; higher mesh counts provide better shielding but also worsen ventilation. Ventilation openings should ideally be located on the sides of the cabinet or in non-primary radiation directions. Shielded cooling fans with conductive blades and frames, and proper grounding, can also be used. In extremely demanding applications, independent air ducts can be used to isolate the heat dissipation path from the internal equipment. The design must balance shielding effectiveness, ventilation volume, and cost, and be validated through testing. Eintech provides standardized shielded ventilation window components that can be easily integrated into inverter cabinet designs to achieve the best balance between shielding and heat dissipation.