This part of IEC 34 identifies the circuit arrangements and the methods of movement of the coolant in rotating electrical machines, classifies the methods of cooling and gives a designation system for them. The designation of the method of cooling consists of the letters "IC", followed by numerals and letters representing the circuit arrangement, the coolant and the method of movement of the coolant. A complete designation and a simplified designation are defined. The complete designation system is intended for use mainly when the simplified system is not applicable. The complete designations, as well as the simplified designations, are illustrated in the tables of annex a for some of the most frequently used types of rotating machines, together with sketches of particular examples.