The invention relates to an air-cooled frequency converter, especially for construction site equipment, such as internal and external vibrators which are operated at a higher frequency than the existing electricity supply, said frequency converter comprising a housing and preferably being connected to a separation transformer for producing a protective extra-low voltage. The housing is divided into a converter receiving element surrounding a plate chamber, and a housing section connected to the receiving element and used as a cooling region, inside which cooling air channels and a fan for conveying the cooling air through the cooling air channels are arranged. The configuration of the housing in the cooling region are created by annular profiled elements which are cross-cut as desired, surround each other in an interspaced manner, and are coaxially arranged in relation to each other.