Uninterruptible power supply for a rotary printing machine

The invention relates to a power supply for a rotary printing machine (3) from a customer network (1). In order to maintain the printing machines in a controlled operating state in the event of mains voltage disturbances and failures, the rotary printing machine (3) is supplied by an uninterruptible power supply (UPS) (2), which is connected on the input side to the customer network (1).