A frequency converter unit includes a unit body, input bus bar means and output bus bar means. The input bus bar means have a plurality of input side bus bars spaced apart in a first direction, and the output bus bar means have a plurality of output side bus bars spaced apart in the first direction, which is perpendicular to an installation direction of the frequency converter unit. Each of the plurality of input side bus bars and the plurality of output side bus bars includes an aperture configured to connect the bus bar to a counterpart contact in a frame with a bolt-nut connection.