IEC 60034-7 Ed. 2.1 b:2001, Rotating electrical machines - Part 7: Classification of types of construction, mounting arrangements and terminal box position (IM Code)

Gives two systems of classification: an alpha-numeric designation applicable to machines with endshield bearings and only one shaft extension (code I) and an all-numeric designation applicable to a wide range of types of machines (code II) including types covered by code I.