The requirements in this standard are applied to 50 Hz and 60 Hz, two-pole and four pole, cylindrical-rotor synchronous generators driven by steam turbines and/or by combustion gas turbines. The drive may be direct or through a gearbox or other device that permits different speeds for the turbine and the generator. The generators covered by this standard are to have rated outputs of 10 MVA and above.

The requirements in this standard apply to all 50 Hz and 60 Hz, two-pole and four-pole, cylindrical-rotor synchronous generators driven by steam turbines and/or by combustion gas turbines. The drive may be direct or through a gearbox or other device that permits different speeds for the turbine and the generator.The generators covered by this standard are to have rated outputs of 10 MVA and above. Cylindrical-rotor, two-pole and four-pole generators below this rating are generally covered by NEMA MG 1.

The purpose of this standard is to establish a base set of accepted requirements for 50 Hz and 60 Hz cylindrical-rotor electrical generators above 10 MVA driven by steam turbines or combustion turbines that can be used in the specification of a new generator. It is also intended that the standard provides guidance for determining other requirements that may stem from coordination with the specific application including the prime mover characteristics, site conditions, and system interconnection.