IEC 60034-4-1:2018 applies to three-phase synchronous machines of 1 kVA rating and larger and describes methods intended to be used for machines having an excitation winding with slip-rings and brushes for their supply. Synchronous machines with brushless excitation require special effort for some of the tests. For machines with permanent magnet excitation, there is a limited applicability of the described tests, and special precautions should be taken against irreversible demagnetization.