Specifies the calculation of efficiency from the summation of individual losses or from measurement of total losses. Specifies particular losses to be included for various types of machine. Details calibrated machine test, zero power-factor test, retardation test and electrical back-to-back test. This Standard is technically equivalent to and reproduced from IEC 34-2:1972 including Amd. 1:1995 and Amd. 2:1996.