[en] The article examines the structure of recent large-capacity diesel generators, and discusses solutions to the problems of mechanical strength resulting from increased size. Emphasis is placed on torsional vibration; an outline of a calculation program, a comparison of measured and calculated values, and a calculation method for the spider, fan, rotor coil and other rotating parts is presented. The article also reports the results of measurements of stress distribution using a plastic model, which was carried out in order confirm the bending-fatigue strength of a skin-stress-type rotor. (auth.)