Applies to three-phase synchronous generators, having rated outputs of 10 MVA and above driven by steam turbines or combustion gas turbines. Provides common requirements as well as specific requirements for air, hydrogen or liquid cooled synchronous generators and supplements the basic requirements given in IEC 60034-1. Gives also the precautions to be taken when using hydrogen cooled generators. The scope of this new edition has been limited with respect to the previous edition.