This part of IEC 60034 specifies efficiency classes for single-speed electric motors that are
rated according to IEC 60034-1 or IEC 60079-0, are rated for operation on a sinusoidal
voltage supply and:
• have a rated power P_N from 0,12 kW to 1 000 kW;
• have a rated voltage U_N above 50 V up to 1 kV;
• have 2, 4, 6 or 8 poles;
• are capable of continuous operation at their rated power with a temperature rise within the
specified insulation temperature class;
NOTE 1 Most motors covered by this standard are rated for duty type S1 (continuous duty). However, some motors that are rated for other duty cycles are still capable of continuous operation at their rated power and these motors are also covered.
• are marked with any ambient temperature within the range of –20 °C to + 60 °C;
NOTE 2 The rated efficiency and efficiency classes are based on 25 °C ambient temperature according to IEC 60034-2-1.
NOTE 3 Motors rated for temperatures outside the range – 20 °C and + 60 °C are considered to be of special construction and are consequently excluded from this standard.
NOTE 4 Smoke extraction motors with a temperature class of up to and including 400 °C are covered by this standard.
• are marked with an altitude up to 4 000 m above sea level.
NOTE 5 The rated efficiency and efficiency class are based on a rating for altitudes up to 1 000 m above sea level.