An electrical charging system having a rectifier which is supplied with energy via an input. An inverter whose alternating voltage side is connected, via phase conductors, to windings of a rotating field machine and whose direct voltage side can be connected to an energy accumulator to be charged. A first current path section passes current, supplied by the rectifier, into the charging system via the plus terminal or pole of the rectifier and the rotating field machine to the inverter. The first current path section passes the current via phase windings of the rotating field machine, such that the first current path section comprises a first switch, which can selectively interrupt the first current path section. The charging system can operate, by the first switch and at least one phase winding in the first current path section, as a step-up and step-down converter in the direction toward an energy accumulator.