Pot tending machine for a series of electrolysis cells designed for the production of aluminum by igneous electrolysis including: a) an overhead traveling crane which can be relocated above said electrolysis cells, b) a tool carriage onto which is fixed a service module comprising tools; c) a tapping winch, interdependent of said overhead traveling crane, designed to grasp and position near cell a tapping assembly including a ladle, a tapping tube and a vacuum device; d) a freestanding device able to generate compressed air; characterized in that said compressed air generating device of includes a first compressor, able to provide a flow of compressed air at least equal to the minimum air flow necessary for operations other than tapping, and at least one second compressor mounted in such a way that, when operating simultaneously with said first compressor, the unit provides a flow of compressed air at least equal to the minimum output of air necessary during tapping.