IEC 60041:1991 specifies methods for any size and type of impulse or reaction turbine, storage pump or pump turbine. Determines whether the contract guarantees have been fulfilled and deals with the rules governing these tests as well as the methods of computing the results and the content and style of the final report. Replaces IEC 60198 (1966) and IEC 60607 (1978). The contents of the corrigendum of March 1996 have been included in this copy.