IEC 60034-3:2020 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 document supplements basic requirements for rotating machines given in IEC 60034-1.This seventh edition cancels and replaces the sixth edition published in 2007. This edition includes the following significant technical changes with respect to the previous edition:- title modified;- scope extended to synchronous compensators;- rotor overcurrent requirements added;- impact of stator harmonics on rotor unbalanced load capability introduced;- synchronisation requirements added;- adjustments of temperatures or temperature rise revised for gas turbine applications;- requirements for auxiliaries updated.