A centrifugal compressor is provided. The centrifugal compressor includes a housing and a rotatable assembly mounted for rotation about an axis within the housing. The rotatable assembly includes an impeller forming part of a compressor stage. A first air intake is located at a first end of the apparatus, the first air intake providing an air source for the compressor stage and a second air intake is located at a second end of the apparatus. A thrust plate is attached to the rotatable assembly, the thrust plate including at least one interior channel so that air entering the second air inlet passes through the at least one interior channel.