Abstract: A method for operating a transformerless inverter includes operating first and second half-bridges of the inverter using a unipolar clocking method as a first clocking method, determining a value of a grid-frequency stray current at the DC terminals of the inverter during the unipolar clocking method, and when a limit value is exceeded by the stray current value, operating the first and second half-bridges of the inverter using a stray-current-reducing clocking method as a second clocking method in which the first half-bridge provides an AC voltage at the first AC output, wherein an amplitude of the AC voltage is less than 50% of the amplitude of a voltage amplitude of the grid, and the second half-bridge provides a difference voltage between the grid voltage and the voltage provided by the first half-bridge at the first AC output.

Abstract: A method for operating a transformerless inverter includes operating first and second half-bridges of the inverter using a unipolar clocking method as a first clocking method, determining a value of a grid-frequency stray current at the DC terminals of the inverter during the unipolar clocking method, and when a limit value is exceeded by the stray current value, operating the first and second half-bridges of the inverter using a stray-current-reducing clocking method as a second clocking method in which the first half-bridge provides an AC voltage at the first AC output, wherein an amplitude of the AC voltage is less than 50% of the amplitude of a voltage amplitude of the grid, and the second half-bridge provides a difference voltage between the grid voltage and the voltage provided by the first half-bridge at the first AC output.

Abstract: For defining an electric potential of input lines of an inverter with respect to ground, in all current-carrying output lines of the inverter capacitors are arranged and charged to a DC voltage in order to shift the electric potential of the input lines with respect to a reference potential present at the current-carrying output lines of the inverter by this DC voltage.

Abstract: For defining an electric potential of input lines of an inverter with respect to ground, in all current-carrying output lines of the inverter capacitors are arranged and charged to a DC voltage in order to shift the electric potential of the input lines with respect to a reference potential present at the current-carrying output lines of the inverter by this DC voltage.

Abstract: A clamping device having clamping surfaces disposed on both sides of a gap and being movable relative to one another, at least one of the clamping surfaces being formed by lateral surfaces of a plurality of plate-type spring elements, includes, at the lateral surface of each spring element, local projections facing the gap and separated by returns, the spring elements being arranged in a stack so that a projection of a spring element is adjoined by respective returns of adjacent spring elements, each of the projections being disposed over a recess formed in the respective spring element; and a printing cylinder for a printing machine, including the clamping device.

Abstract: A device for correcting trapezoidal register deviations, which includes clamping a trailing edge of a printing plate on a plate cylinder at a plurality of partial sections thereof, making a specimen print for determining register deviations, and correcting register deviations by changing lateral spacing of two of the partial sections engaged in the clamping, and prior to correcting the register deviations, applying an additional clamping force to the two partial sections, the lateral spacing of which is changed; and a device for performing the method.

Abstract: A quick-action clamping device for fastening a printing plate on a plate cylinder in a printing machine by a fixed clamping bar and a displaceable clamping bar which are able to be brought into a clamping position and a plate-changing position, respectively, includes a spring device for resiliently pressing the displaceable clamping bar into the clamping position with a holding force for clamping a printing plate between the displaceable clamping bar and the fixed clamping bar, and at least one re-set element for returning the displaceable clamping bar to the plate-changing position against the holding force.

Abstract: A clamping and tensioning device for clamping a printing plate on a cylinder of a printing machine includes a tensioning bar and a clamping bar having substantially radially extending, mutually opposing clamping surfaces for gripping therebetween a bent end of a printing plate, the tensioning bar being formed as a pivotal double lever, tension spring devices engageable with the tensioning bar for applying a tensioning force thereto in a tensioning direction, adjusting devices engageable with the tensioning bar and actuatable for pivoting the tensioning bar against the tensioning force applied by the tension spring devices, the clamping bar being formed as a pivotal double lever connected to the tensioning bar, clamping spring devices engaging with the clamping bar for pressing the clamping surface of the clamping bar against the corresponding clamping surface of the tensioning bar with a clamping force for holding a printing plate therebetween, the clamping bar being further formed with a holding element, a f

Abstract: Device for keeping a lower covering layer of a two-layer covering on the cylindrical surface of a printing-press cylinder, the two-layer covering also including an upper covering layer covering the keeping device for the lower covering layer, the keeping device for the lower covering layer comprises a keeper rod having a substantially circular cross section and extending along the length of the printing-press cylinder, the keeper rod being braced at one end and at two axially parallel contact locations against the printing-press cylinder so as to position the keeping device in register and in inherently stable condition in circumferential and lateral directions, and locking pins disposed on and distributed in register-maintaining positions along the length of the keeper rod, the locking pins having respective head ends with different length-to-width ratios in the cross section thereof, the head ends being in cooperative engagement in correspondingly shaped holes formed in the lower covering layer.

Abstract: Removable guard on a printing press cylinder formed with a cylinder gap and having end plates at the axial ends thereof includes cover means having a longitudinal split therein, and spring means carried by the cover means, the cover means being yieldingly foldable along the split against the biasing force of the spring means and insertable into the cylinder gap wherein it is unfoldable along the split under the biasing force of the spring means and engageable with the cylinder end plates so as to cover and bridge the cylinder gap.