—T EC H N I C A L N OT E

IEC 60034-2-1 standard on efficiency
measurement methods for low voltage AC motors
The International ElectrotechnicalCommission (IEC) has introduced arevised edition 3.0 of the standard
IEC 60034 Part 2-1: Standard
methods for determining losses
and efficiency from tests (excludingmachines for traction vehicles). The
recent edition 3.0 replaces theedition 2.0 from 2014.

How is efficiency determined?
The efficiency of a motor is defined as the ratio ofoutput (mechanical) power to input (electrical)
power. Determination can be done by using direct
or indirect method.

Of these, the first four types of loss can bedetermined from input power, voltage, current,speed and torque. Additional load losses are
determined from the residual losses defined fromthe partial load tests.

Direct method simply requires a measurement of
the input and output power by means of a power
analyzer. The efficiency of a motor is determined
directly from the measured output power, based on
the rotational speed and torque, and divided by themeasured input power to a motor.

Key changes in Ed. 3.0 vs. Ed. 2.0
The new Edition 3.0 is improving the uncertainty,
accuracy of testing and clarifies the text in different
clauses. Major changes as below:• dynamometer test or method is not recognizedanymore• improved text regarding several clauses• torque measurement• test resistance• state of machine under test and test categories• allowed ambient temperature during testing
increased

Indirect measurement is based on the loss
segregation method leading to the sum of losses
ie. total losses, calculated in each six load point as
defined in the standard. Total losses are thensubstracted from the input power thus giving theoutput power used for the determination of theefficiency in each load point.
Motor losses can be divided in the following groups:• load losses that are of stator winding and rotor
losses• iron losses• friction and windage losses• additional load losses (stray load losses)

These improvements do not make any changes in
the loss calculation and efficiency determination
when comparing Ed. 3.0 and Ed. 2.0.

How do the efficiency figures differ
when tested according to Ed. 3.0 and Ed. 2.0?
No changes in the loss calculation nor results
affecting to the losses and finally to the efficiency
determination.
The indirect method as defined in the standard IEC
60034-2-1 is almoust identiacl to the methods
defined in IEEE 112 Method B and in CSA 390-98.
Today the testing standard IEC 60034-2-1 is also
recognized by the US Department of Energy.
How can motor users identify
which measuring method has been used?
The motor documentation must state which methodwas used.

International Efficiency (IE) classesStandard IEC 60034-30-1, published in March 2014,
defines four IE (International Efficiency) classes ofsingle-speed, “line operated AC motors” that arerated for sinusoidal voltage supply and;• have 2, 4, 6 or 8 poles• rated power from 0.12 kW up to 1000 kW• rated voltage from 50V up to 1000V• are capable of continuous operation at their rated
power with a temperature rise within the specified
thermal class• marked within the ambient range of -20°C to+60°C (any ambient temperature)• marked with an altitude up to 4000m
More detailed information about the scope as well
as exclusions can be found from the IEC 60034-30-1

Please note that efficiency values provided bydifferent motor manufacturers are comparable only
if the same measuring method has been used.

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potential errors or possible lack of information in this document.

iEC

International Electrotechnical Commission

IEEE

Institute of Electrical and Electronics Engineers

CSA

Canadian Standards AssociationCSA

European Norm

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Copyright© 2024 ABB
All rights reserved

9AKK107318 EN 04-2024

Key to abbreviations:

How does ABB apply the new edition of thestandard?
Since these are no changes in the measurement,
loss calculation nor efficiency determination thenew edition can be referenced in our catalogs andtest reports without further notice. Under theefficiency testing standard (IEC 60034-2-1 Ed.2.0
from 2014 or Ed.3.0 from 2024);• ABB has calculated efficiency values according toindirect method, with additional losses
determined from measurement, which is thepreferred low uncertainty method outlined in thestandard.
• equipment used by ABB are of higher accuracy
class than defined in the standard.
• ABB provides efficiency values according toedition 2.0 or 3.0
IEC 60034-2-1 and publish the values in the printed
technical catalogs.