IEC 60034-18-1:2010 deals with the general guidelines for functional evaluation of electrical insulation systems, used or proposed to be used in rotating electrical machines within the scope of IEC 60034-1, in order to qualify them. The main changes of this new edition with respect to the previous one are as follows: - provides general guidelines for functional evaluation of different types of windings as before but beyond that for electrical evaluation of windings which are electrically stressed by converter-supply; - is now focused on general guidelines with all technical details of procedures and qualification principles moved to the subsequent parts; - details additional general aspects of functional evaluation, particularly the statistical procedure for comparison between reference and candidate insulation systems and the evaluation of minor component or manufacturing changes; - contains a new acceptance test for verifying the expected production quality level of the insulation systems; - restricts the classification of insulation systems as a result of the functional evaluation to thermal classification.