Abstract: Briefly, the invention comprises an improved cooling fin arrangement for a triphasic bridge rectifier used in conjunction with a three phase alternator in an automotive vehicle. The heat transfer ability of a metallic air core heat sink and radiator is more than doubled by increasing its thickness (and thus its exposed surface area) and by providing a cutout groove allowing the air to flow in two directions thus reducing the air flow resistance. An improved cover plate cooperates with the newly provided air flow paths and also provides simplified connectors for the electrical elements.