A voltage generator comprising a first and a second mechanical system which systems are arranged for relative rotation to one another by means of a shaft incorporated in the first system being supported in bearings mounted in the second system, the shaft of the first system carrying an off-axis biassing weight of sufficient magnitude to restrain by gravitational force the first system from rotation when the shaft is horizontally orientated and the second system is rotated about an axis coincident with the shaft axis, a permanent magnet forming part of one of the systems and an armature winding being carried by the other whereby rotation of the second system about the first causes voltages to be induced in the armature winding.
Printing machine with at least one printing unit having rotating cylinders, comprising an energy converter disposed at least partially in one of the cylinders for converting at least some rotational energy of the cylinder into electrical energy and an energy storage device also disposed in the cylinder for storing the electrical energy.
