IEC 60034-2-1:2014(B) is intended to establish methods of determining efficiencies from tests, and also to specify methods of obtaining specific losses. This standard applies to d.c. machines and to a.c. synchronous and induction machines of all sizes within the scope of IEC 60034-1. This new edition includes the following significant technical changes with respect to the previous edition: grouping of the test methods into preferred methods and methods for field or routine testing; addition of the details of the requirements regarding instrumentation; addition of the description of tests required for a specific method in the same sequence as requested for the performance of the test.