WG 31 - TC 2/WG 31

IEC 60034-30-1:2025 specifies efficiency classes for single-speed electric motors that are rated in accordance with IEC 60034‑1 or IEC 60079‑0 and are rated for operation on a sinusoidal either 50 Hz or 60 Hz, or both voltage supply.
The motors within this document:
- have a rated power PN from 0,12 kW to 1 000 kW;
- have a rated voltage UN from 50 V up to and including 1 000 V;
- 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 document 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 by this document.
- are marked with any ambient temperature within the range of –30 °C to +60 °C;
NOTE 2 The rated efficiency and efficiency classes are based on 25 °C ambient temperature in accordance with IEC 60034‑2‑1.
NOTE 3 Motors exclusively rated for temperatures outside the range – 30 °C and +60 °C are considered to be of special construction and are consequently excluded from this document.
NOTE 4 Smoke extraction motors with a temperature class of up to and including 400 °C are covered by this document.
- 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.
This document establishes a set of nominal efficiency values based on supply frequency, number of poles and motor output power. No distinction is made between motor technologies, supply voltage or motors with increased insulation designed specifically for converter operation even though not all motor technologies are capable of reaching the higher efficiency classes (see Table 1). This makes different motor technologies fully comparable with respect to their energy efficiency potential.
The efficiency of power-drive systems is not covered by this document. Motor losses due to harmonic content of the supply voltage, losses in cables, filters and frequency-converters, are not covered.
Motors with flanges, feet or shafts with mechanical dimensions different from IEC 60072‑1 are covered by this document.
Geared motors are covered by this document including those incorporating non-standard shafts and flanges.
This document does not apply to the following:
- Single-speed motors with 10 or more poles or multi-speed motors.
- Motors with mechanical commutators (such as DC motors).
- Motors completely integrated into a machine (for example pump, fan and compressor) that cannot be practically tested separately from the machine even with provision of a temporary end-shield and drive-end bearing. This means the motor: a) shares common components (apart from connectors such as bolts) with the driven unit (for example, a shaft or housing) and b) is not designed in such a way as to enable the motor to be separated from the driven unit as an entire motor that can operate independently of the driven unit. That is, for a motor to be excluded from this document, the process of separation shall render the motor inoperative.
- Totally enclosed air-over machines (TEAO, IC418), i.e. totally enclosed frame-surface cooled machines intended for exterior cooling by a ventilating means external to the machine. Efficiency testing of such motors can be performed with the fan removed and the cooling provided by an external blower with a similar airflow rate as the original fan.
- Motors with integrated frequency converters (compact drives) when the motor cannot be tested separately from the converter. Energy efficiency classification of compact drives is based on the complete product (PDS, ie. Power Drive System) and is defined in IEC 61800‑9‑2.
NOTE 6 A motor is not excluded when the motor and frequency-converter can be separated, and the motor can be tested independently of th

IEC 60034-30-3:2024 specifies efficiency classes for fixed-speed three-phase high-voltage cage induction motors in accordance with IEC 60034-1 that
- have a rated voltage exceeding 1 000 V, but not exceeding 11 kV;
- have a rated power from 200 kW to 2 000 kW;
This document provides the global harmonization of energy-efficiency classes of three-phase cage induction motors with rated voltage above 1 000 V that are rated for direct online starting and fixed-speed operation at a 50 Hz or 60 Hz supply with sinusoidal voltage.

IEC TS 60034-30-2:2016(E) specifies efficiency classes for variable speed rotating electric machines not covered in IEC 60034-30-1. The classification only covers machines designed for operation with sinusoidal fundamental current that are not designed to be operated direct on-line (grid), for example permanent magnet synchronous machines with and without additional reluctance torque, sinusoidal reluctance synchronous machines and synchronous machines with DC field windings.

IEC 60034-30-1:2014 specifies efficiency classes for single-speed electric motors that are rated according to IEC 60034-1 or IEC 60079-0, for operation on a sinusoidal voltage supply. This standard establishes a set of limit efficiency values based on frequency, number of poles and motor power. No distinction is made between motor technologies, supply voltage or motors with increased insulation designed specifically for converter operation even though these motor technologies may not all be capable of reaching the higher efficiency classes. This makes different motor technologies fully comparable with respect to their energy efficiency potential.

IEC/TS 60034-31:2010 provides a guideline of technical aspects for the application of energy-efficient, three-phase, electric motors. It not only applies to motor manufacturers, original equipment manufacturers, end users, regulators and legislators but to all other interested parties. Is applicable to all electrical machines covered by IEC 60034-30.

IEC 60034-30:2008 specifies efficiency classes for single-speed, three-phase, 50 Hz and 60 Hz, cage-induction motors.