This part of IEC 60034 applies to large three-phase synchronous generators, having rated outputs of 10 MVA and above driven by steam turbines or combustion gas turbines. Also included are synchronous MVAr compensators of the same output range connected to a grid for the purpose of exchanging reactive power. This standard supplements basic requirements for rotating machines given in IEC 60034-1. Common requirements are prescribed together with specific requirements for air, hydrogen or liquid cooled synchronous generators or compensators. This part of IEC 60034 also gives the precautions to be taken when using hydrogen cooled generators including: rotating exciters driven by synchronous generators; auxiliary equipment needed for operating the generators; parts of the building where hydrogen might accumulate. NOTE 1 These requirements also apply to a synchronous generator driven by both a steam turbine and a combustion gas turbine as part of a single shaft combined cycle unit. NOTE 2 These requirements do not apply to synchronous generators driven by water (hydraulic) turbines or wind turbines. NOTE 3 The precautions to be taken when using hydrogen are valid for all cases where hydrogen is used as a coolant.