Abstract: An electrical apparatus having a cooling system includes a first cover to cover a first part of the electrical apparatus to be cooled and a second cover substantially enclosing the first cover to define a surrounding space. A base plate on which the first cover is mounted defines an environmentally-sealed enclosure that houses the first part of electrical apparatus. A first circulation device causes air to circulate in the environmentally-sealed enclosure and a second circulation device causes a cooling fluid to circulate around the surrounding space. A heat transfer structure is positioned on each side of the first cover. A third cover is mounted to an opposite side of the base plate from the first cover to define a second enclosure that houses a second part of the electrical apparatus to be cooled. A heat exchange structure is positioned within the second enclosure. The second circulation device is arranged to drive cooling fluid both through the heat exchange structure and through the surrounding space.

Abstract: An electrical apparatus and cooling system is described, having an arrangement particularly suited to electrical apparatus incorporating devices which produce a significant amount of heat, such as vacuum tube devices. The electrical apparatus has an enclosure cover (22) and a base plate (6) defining an enclosure (20) containing the part of the electrical apparatus to be cooled, and an outer cover (4) enclosing the first to create a surrounding space (26) therebetween. Means (22, 76 and 78) are provided to transfer heat from the enclosure to the surrounding space. Cooling fans (50) and (52) located outside of the surrounding space create a flow of air which passes through a heat exchange structure mounted (54) adjacent the enclosure to provide a cooling effect. Some of the air flow is also ducted through the surrounding space, to cool the enclosure cover (22).