IEC 60034-2-1:2024
(Main)Rotating electrical machines - Part 2-1: Standard methods for determining losses and efficiency from tests (excluding machines for traction vehicles)
Rotating electrical machines - Part 2-1: Standard methods for determining losses and efficiency from tests (excluding machines for traction vehicles)
IEC 60034-2-1:2024 is intended to establish methods of determining efficiencies from tests, and also to specify methods of obtaining specific losses. This document applies to DC machines and to AC synchronous and induction machines of all sizes within the scope of IEC 60034-1 rated for mains operation. These methods may be applied to other types of machines such as rotary converters, AC commutator motors and single-phase induction motors. This third edition cancels and replaces the second edition of IEC 60034-2-1 published in 2014. This edition includes the following significant technical changes with respect to the previous edition:
- Harmonization of layout and requirements with IEC 60034-2-2 and IEC 60034-2-3.
Machines électriques tournantes - Partie 2-1: Méthodes normalisées pour la détermination des pertes et du rendement à partir d'essais (à l'exclusion des machines pour véhicules de traction)
L'IEC 60034-2-1:2024 a pour objet de définir les méthodes de détermination du rendement à partir d'essais et également de spécifier les méthodes qui permettent de déterminer des pertes spécifiques. Le présent document s'applique aux machines à courant continu ainsi qu'aux machines à courant alternatif, synchrones et à induction, de toutes dimensions, qui entrent dans le domaine d'application de l'IEC 60034-1 et assignées pour un fonctionnement sur secteur. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- Harmonisation de la disposition et des procédures avec l'IEC 60034-2-2 et l'IEC 60034-2-3.
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IEC 60034-2-1 ®
Edition 3.0 2024-03
REDLINE VERSION
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STANDARD
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Rotating electrical machines –
Part 2-1: Standard methods for determining losses and efficiency from tests
(excluding machines for traction vehicles)
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IEC 60034-2-1 ®
Edition 3.0 2024-03
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Rotating electrical machines –
Part 2-1: Standard methods for determining losses and efficiency from tests
(excluding machines for traction vehicles)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.160.01 ISBN 978-2-8322-8542-8
– 2 – IEC 60034-2-1:2024 RLV © IEC 2024
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Symbols and abbreviated terms . 13
4.1 Symbols . 13
4.2 Additional subscripts . 14
5 Basic requirements . 15
5.1 Direct and indirect efficiency determination . 15
5.2 Uncertainty . 15
5.3 Preferred methods and methods for customer-specific acceptance tests,
field-tests or routine-tests . 16
5.4 Power supply . 16
5.4.1 Voltage . 16
5.4.2 Frequency . 16
5.5 Instrumentation . 16
5.5.1 General . 16
5.5.2 Measuring instruments for electrical quantities . 16
5.5.3 Torque measurement . 17
5.5.4 Speed and frequency measurement . 18
5.5.5 Temperature measurement . 18
5.6 Units . 18
5.7 Resistance . 18
5.7.1 Test resistance . 18
5.7.2 Winding temperature . 18
5.7.3 Correction to reference coolant temperature . 19
5.8 State of the machine under test and test categories . 19
5.9 Excitation circuit measurements . 20
5.10 Ambient temperature during testing . 21
6 Test methods for the determination of the efficiency of induction machines . 21
6.1 Preferred testing methods . 21
6.1.1 General . 21
6.1.2 Method 2-1-1A – Direct measurement of input and output . 22
6.1.3 Method 2-1-1B – Summation of losses, additional load losses according
to the method of residual loss . 24
6.1.4 Method 2-1-1C – Summation of losses with additional load losses from
assigned allowance . 33
6.2 Testing methods for field or routine-testing . 38
6.2.1 General . 38
6.2.2 Method 2-1-1D – Dual supply back-to-back-test . 39
6.2.3 Method 2-1-1E – Single supply back-to-back-test . 40
6.2.4 Method 2-1-1F – Summation of losses with additional load losses
determined by test with rotor removed and reverse rotation test . 41
6.2.5 Method 2-1-1G – Summation of losses with additional load losses
determined by Eh-star method . 46
6.2.6 Method 2-1-1H – Determination of efficiency by use of the equivalent
circuit parameters . 51
7 Test methods for the determination of the efficiency of synchronous machines . 57
7.1 Preferred testing methods . 57
7.1.1 General . 57
7.1.2 Method 2-1-2A – Direct measurement of input and output . 58
7.1.3 Method 2-1-2B – Summation of separate losses with a rated load
temperature test and a short circuit test . 59
7.1.4 Method 2-1-2C – Summation of separate losses without a full load test . 65
7.2 Testing methods for field or routine testing . 67
7.2.1 General . 67
7.2.2 Method 2-1-2D – Dual supply back-to-back-test . 67
7.2.3 Method 2-1-2E – Single supply back-to-back-test . 68
7.2.4 Method 2-1-2F – Zero power factor test with excitation current from
Potier-, ASA- or Swedish-diagram . 70
7.2.5 Method 2-1-2G – Summation of separate losses with a load test without
consideration of additional load losses . 74
8 Test methods for the determination of the efficiency of DC machines . 75
8.1 Testing methods for field or routine testing . 75
8.2 Method 2-1-3A – Direct measurement of input and output . 76
8.2.1 General . 76
8.2.2 Test procedure . 77
8.2.3 Efficiency determination. 77
8.3 Method 2-1-3B – Summation of losses with a load test and DC component of
additional load losses from test . 78
8.3.1 General . 78
8.3.2 Test procedure . 79
8.4 Method 2-1-3C – Summation of losses with a load test and DC component of
additional load losses from assigned value . 85
8.4.1 General . 85
8.4.2 Test procedure . 86
8.4.3 Efficiency determination. 87
8.5 Method 2-1-3D – Summation of losses without a load test . 88
8.5.1 General . 88
8.5.2 Test procedure . 89
8.5.3 Efficiency determination. 90
8.6 Method 2-1-3E – Single supply back-to-back test . 91
8.6.1 General . 91
8.6.2 Test procedure . 91
8.6.3 Efficiency determination. 92
Annex A (normative) Calculation of values for the Eh-star method . 93
Annex B (informative) Types of excitation systems . 96
Annex C (informative) Induction machine slip measurement . 97
Annex D (informative) Test report template for method 2-1-1B . 99
Bibliography . 100
Figure 1 – Torque measuring devices . 17
Figure 2 – Sketch for torque measurement test . 22
Figure 3 – Efficiency determination according to method 2-1-1A . 23
Figure 4 – Efficiency determination according to method 2-1-1B . 26
Figure 5 – Smoothing of the residual loss data . 32
– 4 – IEC 60034-2-1:2024 RLV © IEC 2024
Figure 6 – Efficiency determination according to method 2-1-1C . 35
Figure 7 – Vector diagram for obtaining current vector from reduced voltage test . 36
Figure 8 – Assigned allowance for additional load losses P . 37
LL
Figure 9 – Efficiency determination according to method 2-1-1D . 39
Figure 10 – Sketch for dual supply back-to-back test . 39
Figure 11 – Efficiency determination according to method 2-1-1E . 40
Figure 12 – Efficiency determination according to method 2-1-1F . 43
Figure 13 – Efficiency determination according to method 2-1-1G . 48
Figure 14 – Eh-star test circuit . 49
Figure 15 – Induction machine, T-model with equivalent iron loss resistor . 51
Figure 16 – Efficiency determination according to method 2-1-1H . 52
Figure 17 – Induction machines, reduced model for calculation . 55
Figure 18 – Sketch for torque measurement test . 58
Figure 19 – Efficiency determination according to method 2-1-2A . 58
Figure 20 – Efficiency determination according to method 2-1-2B . 60
Figure 21 – Efficiency determination according to method 2-1-2C . 66
Figure 22 – Efficiency determination according to method 2-1-2D . 67
Figure 23 – Sketch for dual supply back-to-back test ( I If, f ) . 68
M GM G
Figure 24 – Efficiency determination according to method 2-1-2E . 69
Figure 25 – Single supply back-to-back test for synchronous machines . 69
Figure 26 – Efficiency determination according to method 2-1-2F . 70
Figure 27 – Efficiency determination according to method 2-1-2G . 75
Figure 28 – Sketch for torque measurement test . 76
Figure 29 – Efficiency determination according to method 2-1-3A . 77
Figure 30 – Efficiency determination according to method 2-1-3B . 79
Figure 31 – Sketch for single supply back-to-back test for determination of DC
component of additional load losses . 83
Figure 32 – Efficiency determination according to method 2-1-3C . 86
Figure 33 – Efficiency determination according to method 2-1-3D . 89
Figure 34 – Efficiency determination according to method 2-1-3E . 91
Figure 35 – Sketch for single supply back-to-back test . 91
Figure C.1 – Slip measurement system block diagram . 98
Table 1 – Reference temperature . 19
Table 2 – Induction machines: preferred testing methods . 21
Table 3 – Induction machines: other methods . 39
Table 4 – Synchronous machines with electrical excitation: preferred testing methods . 57
Table 5 – Synchronous machines with permanent magnets: preferred testing methods . 57
Table 6 – Synchronous machines: other methods . 67
Table 7 – DC machines: test methods . 76
Table 8 – Multiplying factors for different speed ratios . 87
==
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ROTATING ELECTRICAL MACHINES –
Part 2-1: Standard methods for determining losses and efficiency
from tests (excluding machines for traction vehicles)
FOREWORD
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition IEC 60034-2-1:2014. A vertical bar appears in the margin
wherever a change has been made. Additions are in green text, deletions are in
strikethrough red text.
– 6 – IEC 60034-2-1:2024 RLV © IEC 2024
IEC 60034-2-1 has been prepared by IEC technical committee 2: Rotating machinery. It is an
International Standard.
This third edition cancels and replaces the second edition of IEC 60034-2-1 published in 2014.
This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
Harmonization of layout and requirements with IEC 60034-2-2 and IEC 60034-2-3.
The text of this International Standard is based on the following documents:
Draft Report on voting
2/2165/FDIS 2/2177/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 60034 series, published under the general title Rotating electrical
machines, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.
ROTATING ELECTRICAL MACHINES –
Part 2-1: Standard methods for determining losses and efficiency
from tests (excluding machines for traction vehicles)
1 Scope
This part of IEC 60034 is intended to establish methods of determining efficiencies from tests,
and also to specify methods of obtaining specific losses.
This document applies to DC machines and to AC synchronous and induction machines of all
sizes within the scope of IEC 60034-1 rated for mains operation.
NOTE These methods may be applied to other types of machines such as rotary converters, AC commutator motors
and single-phase induction motors.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60027-1, Letter symbols to be used in electrical technology – Part 1: General
IEC 60034-1:20102022, Rotating electrical machines – Part 1: Rating and performance
IEC 60034-4:2008, Rotating electrical machines – Part 4: Methods for determining synchronous
machine quantities from tests
IEC 60034-4-1:2018, Rotating electrical machines – Part 4-1: Methods for determining
electrically excited synchronous machine quantities from tests
IEC 60034-19, Rotating electrical machines – Part 19:Specific test methods for DC machines
on conventional and rectifier-fed supplies
IEC 60034-29, Rotating electrical machines – Part 29: Equivalent loading and superposition
techniques – Indirect testing to determine temperature rise
IEC 60034-30-1, Rotating electrical machines – Part 30-1: Efficiency classes of line operated
AC motors (IE code)
IEC 60051(all parts), Direct acting indicating analogue electrical measuring instruments and
their accessories
IEC 60051-1, Direct acting indicating analogue electrical measuring instruments and their
accessories – Part 1: Definitions and general requirements common to all parts
– 8 – IEC 60034-2-1:2024 RLV © IEC 2024
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60034-1, IEC 60051-1
and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
efficiency
ratio of output power to input power expressed in the same units and usually given as a
percentage
3.2
direct efficiency determination
method by which the determination of efficiency is made by measuring directly the input power
and the output power
3.3
dynamometer
device for measuring torque applied to the rotating part of the machine under test. It is equipped
with means for measuring and indicating torque and speed, and is not limited to a cradle base
construction. An in-line torque transducer may be used to provide a direct measurement of
torque at the shaft of the machine under test.
3.4
dynamometer test
test in which the mechanical power output of a machine acting as a motor is determined by a
dynamometer. Also a test in which the mechanical input power of a machine acting as a
generator is determined by a dynamometer.
3.3
dual-supply back-to-back test
test in which two identical machines are mechanically coupled together, and the total losses of
both machines are calculated from the difference between the electrical input to one machine
and the electrical output of the other machine
3.4
indirect efficiency determination
method by which the determination of efficiency is made by measuring the input power or the
output power and determining the total losses. Those losses are added to the output power,
thus giving the input power, or subtracted from the input power, thus giving the output power
3.5
single-supply back-to-back test
test in which two identical machines are mechanically coupled together and are both connected
electrically to the same power system. The total losses of both machines are taken as the input
power drawn from the system
3.6
no-load test
test in which a machine is run as a motor providing no useful mechanical output from the shaft,
or when if run as a generator with its terminals open-circuited
3.7
zero power factor test (synchronous machines)
no-load test on a synchronous machine, which is over-excited and operates at a power factor
very close to zero
3.8
equivalent circuit method (induction machines)
test on an induction machine in which the losses are determined by help of an equivalent circuit
model
3.9
test with rotor removed and reverse rotation test (induction machines)
combined test on an induction machine in which the additional load losses are determined from
a test with rotor removed and a test with the rotor running in reverse direction to the rotating
magnetic field of the stator
3.10
short-circuit test (synchronous machines)
test on a synchronous machine in which a machine is run as a generator with its terminals short-
circuited
3.11
locked rotor test
test in which the rotor is locked to prevent rotation
3.12
Eh-star test
test in which the motor is run in star connection on unbalanced voltage
3.13
losses
3.13.1
total losses
P
T
difference between the input power and the output power, equivalent to the sum of the constant
losses (see 3.13.2), the load losses (see 3.13.4), the additional load losses (see 3.13.5) and
the excitation circuit losses (see 3.13.3)
3.13.2
constant losses
P
c
losses incorporating the sum of windage, friction and iron losses
Note 1 to entry: Although these losses change with voltage and load, they are historically called “constant” losses
and the name is retained in this document.
3.13.2.1
constant losses
P
c
sum of the iron losses and the friction and windage losses
3.13.2.1
iron losses
P
fe
losses in active iron and additional no-load losses in other metal magnetic and conductive parts
– 10 – IEC 60034-2-1:2024 RLV © IEC 2024
3.13.2.2
friction and windage losses
P
fw
losses incorporating the sum of windage and friction
3.13.2.2.1
friction losses
losses due to friction (bearings and brushes, if not lifted at rated conditions) not including any
losses in a separate lubricating system
3.13.2.2.2
windage losses
total losses due to aerodynamic friction in all parts of the machine, including power absorbed
in shaft mounted fans, and in auxiliary machines forming an integral part of the machine
Note 1 to entry: Losses in a separate ventilating system should be listed separately.
Note 2 to entry: For machines indirectly or directly cooled by hydrogen, see IEC 60034-1.
3.13.3
excitation circuit losses
3.13.3.1
excitation circuit losses
P
e
sum of the excitation winding losses (see 3.13.3.2), the exciter losses (see 3.13.3.3) and, for
synchronous machines, electrical brush loss (see 3.13.3.5), if any
3.13.3.2
excitation winding losses
P
f
excitation (field) winding losses are equal to the product of the exciting current I and the
e
excitation voltage U
e
3.13.3.3
exciter losses
P
Ed
exciter losses for the different excitation systems (see Annex B) are defined as follows:
a) shaft driven exciter
exciter losses are the power absorbed by the exciter at its shaft (reduced by friction and
windage losses) plus the power P drawn from a separate source at its excitation winding
1E
terminals, minus the useful power which the exciter provides at its terminals. The useful
power at the terminals of the exciter is equal to the excitation winding losses as per 3.13.3.2
plus (in the case of a synchronous machine) the electrical brush losses as per 3.13.3.5.
Note 1 to entry: If the exciter can be decoupled and tested separately its losses can be determined according
to 7.1.3.2.1.5.
Note 2 to entry: Whenever the exciter makes use of separate auxiliary supplies, their consumptions are to be
included in the exciter losses unless they are considered together with the main machine auxiliaries consumption.
b) brushless exciter
exciter losses are the power absorbed by the exciter at its shaft, reduced by friction and
windage losses (when the relevant test is performed on the set of main machine and exciter),
plus the electrical power P from a separate source (if any) absorbed by its field winding
1E
or its stator winding (in the case of an induction exciter), minus the useful power which the
exciter provides at the rotating power converter terminals.
Note 3 to entry: Whenever the exciter makes use of separate auxiliary supplies their consumptions are to be
included in the exciter losses unless they are considered together with the main machine auxiliaries consumption.
Note 4 to entry: If the exciter can be decoupled and tested separately, its losses can be determined according
to 7.1.3.2.1.
c) separate rotating exciter
exciter losses are the difference between the power absorbed by the driving motor, plus the
power absorbed by separate auxiliary supplies, of both driving and driven machines,
including the power supplied by separate source to their excitation winding terminals, and
the excitation power supplied as per 3.13.3.2 and 3.13.3.4. The exciter losses may be
determined according to 7.1.3.2.1.
d) static excitation system
static exciter
excitation system losses are the difference between the electrical power drawn from its
power source, plus the power absorbed by separate auxiliary supplies, and the excitation
supplied as per 3.13.3.2 and 3.13.3.4.
Note 5 to entry: In the case of systems fed by transformers, the transformer losses shall be included in the
exciter losses.
e) excitation from auxiliary winding
auxiliary winding exciter
exciter losses are the copper losses in the auxiliary (secondary) winding and the additional
iron losses produced by increased flux harmonics. The additional iron losses are the
difference between the losses which occur when the auxiliary winding is loaded and when
it is unloaded.
Note 6 to entry: Because separation of the excitation component of losses is difficult, it is recommended to
consider these losses as an integral part of the stator losses when determining overall losses.
In the cases c) and d) no allowance is made for the losses in the excitation source (if any)
or in the connections between the source and the brushes (synchronous machine) or
between the source and the excitation winding terminals (DC machine).
If the excitation is supplied by a system having components as described in b) to e) the
exciter losses shall include the relevant losses of the components pertaining to the
categories listed in Annex B as applicable.
3.13.3.4
separately supplied excitation power
P
1E
excitation power P supplied from a separate power source is:
1E
– for exciter types a) and b) the exciter excitation power (DC or synchronous exciter) or stator
winding input power (induction exciter). It covers a part of the exciter losses P (and further
Ed
losses in induction exciters) while a larger part of P is supplied via the shaft;
e
– for exciter types c) and d) equal to the excitation circuit losses, P = P ;
1E e
= 0, the excitation power being delivered entirely by the shaft. Also,
– for exciter type e) P
1E
P = 0 for machines with permanent magnet excitation.
1E
Exciter types shall be in accordance with 3.13.3.3.
3.13.3.5
brush losses (excitation circuit)
P
b
electrical brush loss (including contact loss) of separately excited synchronous machines
– 12 – IEC 60034-2-1:2024 RLV © IEC 2024
3.13.4
load losses
3.13.4.1
load losses
P
L
sum of the winding (I R) losses (see 3.13.4.2) and the electrical brush losses (see 3.13.3.5), if
any
3.13.4.2
winding losses
winding losses are I R losses:
– in the armature circuit of DC machines;
– in the stator and rotor windings of induction machines;
– in the armature and field windings of synchronous machines
3.13.4.3
brush losses (load circuits)
P
b
electrical brush loss (including contact loss) in the armature circuit of DC machines and in
wound-rotor induction machines
3.13.5
additional load losses (stray-load losses)
P
LL
losses produced in active iron and other metal magnetic and conductive parts by alternating
stray fluxes when the machine is loaded; eddy current losses in winding conductors caused by
load current-dependent flux pulsations and additional brush losses caused by commutation
Note 1 to entry: These losses do not include the additional no-load losses of 3.13.2.2.
3.13.6
short-circuit losses
P P
k sc
current-dependent losses in a synchronous machine and in a DC machine when the armature
winding is short-circuited
3.14
test quantities
3.14.1
terminal voltage
for polyphase AC machines, the arithmetic average of line voltages
3.14.2
line current
for polyphase AC machines, the arithmetic average of line currents
3.14.3
line-to-line resistance
for polyphase AC machines, the arithmetic average of resistances measured between each pair
of terminals
Note 1 to entry: For Y-connected three-phase machines, the phase-resistance is 0,5 times the line-to-line
resistance. For Δ-connected machines, the phase-resistance is 1,5 times the line-to-line resistance.
Note 2 to entry: In Clauses 6 and 7 explanations and formulae given are for three-phase machines, unless otherwise
indicated.
3.14.4
temperature rise
is the machine temperature minus the cooling medium (coolant) temperature as defined by
IEC 60034-1
4 Symbols and abbreviated terms
4.1 Symbols
cos φ is the power factor
f is the supply frequency, Hz
I is the average line current (average of all phases), A
k is the temperature correction factor
θ
–1
n is the operating speed, s
p is the number of pole pairs
P is the power, W
P is the input power at no-load, W
P is the input power, excluding excitation , W
P is the output power, W
P is the brush loss, W
b
P is the output power (shaft power) of a drive motor, W
D
P is the excitation circuit losses, W
e
P is the excitation power supplied by a separate source, W
1E
P is the exciter losses, W
Ed
is the electrical power, excluding excitation, W
P
el
P is the excitation (field) winding losses, W
f
P is the iron losses, W
fe
P is the friction and windage losses, W
fw
P is the constant losses, W
c
P is the load losses, W
L
P is the residual losses, W
Lr
P is the additional-load losses, W
LL
P P is the short-circuit losses, W
k sc
P is the mechanical power, W
mech
P is the total losses, W
T
P is the winding losses, W, where subscript w is generally replaced by a, f,
w
e, s or r (see 4.2)
R is a winding resistance, Ω
___________
This definition assumes sinusoidal voltage and current.
Unless otherwise indicated, the tests in this document are described for motor operation, where P and P are
1 2
electrical input and mechanical output power, respectively.
– 14 – IEC 60034-2-1:2024 RLV © IEC 2024
R is the actual value of the auxiliary resistor for the Eh-star test (see 6.2.5),
eh
Ω
R’ is the typical value of the auxiliary resistor, Ω
eh
R is the field winding resistance, Ω
f
R is the average line-to-line-resistance (average of all phases), Ω
II
R is the average phase-resistance (average of all phases), Ω
ph
s is the slip, in per unit value of synchronous speed
T is the machine torque, N·m
T is the reading of the torque measuring device, N·m
d
T is the torque correction, N·m
c
U is the average terminal voltage (average of all phases), V
U is the terminal voltage at no-load (average of all phases), V
U is the rated terminal voltage, V
N
X is the reactance, Ω
Z= R+×jX is the notation for a complex quantity (impedance as example)
is the absolute value of a complex quantity (impedance as example)
ZZ R+ X
Z is the impedance, Ω
𝛼𝛼 is a temperature coefficient
η is the efficiency
is the initial winding temperature, °C
θ
θ is the ambient temperature, °C
a
θ primary coolant inlet temperature, °C
c
θ is the winding temperature, °C
w
τ is a time constant, s
4.2 Additional subscripts
The following subscripts may be added to symbols to clarify the machine function and to
differentiate values.
Machine components:
a armature
e excitation
f field winding
r rotor
s stator
w winding
U,V,W phase designations
Machine categories:
B booster
D dynamometer
= =
E exciter
G generator
M motor
Operating conditions:
0 no-load
1 input
2 output
av average, mean
d dissipated
el electrical
i internal
k sc short circuit
L test load
lr locked rotor
mech mechanical
N rated
red at reduced voltage
t test
zpf zero power factor test
θ corrected to a reference coolant temperature.
NOTE Further additional subscripts are introduced in relevant subclauses.
5 Basic requirements
5.1 Direct and indirect efficiency determination
Tests can be grouped into the three following categories:
a) input-output power measurement on a single machine. This involves the direct measurement
of electrical or mechanical power into, and mechanical or electrical power out of a machine;
b) electrical input and output measurement on two identical machines mechanically connected
back-to-back. This is done to eliminate the measurement of mechanical power into or out of
the machine;
c) determination of the actual loss in a machine under a particular condition. This is usually
not the total loss but comprises certain loss components.
The methods for determining the efficiency of machines are based on a number of assumptions.
Therefore, it is not recommended that a comparison be made between the values of efficiency
obtained by different methods, because the figures may not necessarily agree.
5.2 Uncertainty
Uncertainty as used in this standard is the uncertainty of determining a true efficiency. It reflects
variations in the test procedure and the test equipment.
Although uncertainty should shall be expressed as a numerical value, such a requirement needs
sufficient testing to determine representative and comparative values.
– 16 – IEC 60034-2-1:2024 RLV © IEC 2024
5.3 Preferred methods and methods for customer-specific acceptance tests, field-
tests or routine-tests
It is difficult to establish specific rules for the determination of efficiency. The choice of test to
be made depends on the information required, the accuracy required, the type and size of the
machine involved and the available field test equipment (supply, load or driving machine).
In the following, the test methods suitable for asynchronous and synchronous machines are
separated into preferred methods and methods for customer-specific acceptance tests, field-
tests or routine tests.
5.4 Power supply
5.4.1 Voltage
The supply voltage shall be in accordance with 7.2 (and 8.3.1 for thermal tests) of
IEC 60034‑1:20102022.
5.4.2 Frequency
During tests, the average supply frequency shall be within ±0,1 % of the frequency required for
the test being conducted.
5.5 Instrumentation
5.5.1 General
Environmental conditions shall be within the recommended range given by the equipment
instrument manufacturer. If appropriate, temperature corrections acco
...
IEC 60034-2-1 ®
Edition 3.0 2024-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Rotating electrical machines –
Part 2-1: Standard methods for determining losses and efficiency from tests
(excluding machines for traction vehicles)
Machines électriques tournantes –
Partie 2-1: Méthodes normalisées pour la détermination des pertes et du
rendement à partir d'essais (à l'exclusion des machines pour véhicules de
traction)
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IEC 60034-2-1 ®
Edition 3.0 2024-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Rotating electrical machines –
Part 2-1: Standard methods for determining losses and efficiency from tests
(excluding machines for traction vehicles)
Machines électriques tournantes –
Partie 2-1: Méthodes normalisées pour la détermination des pertes et du
rendement à partir d'essais (à l'exclusion des machines pour véhicules de
traction)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.160.01 ISBN 978-2-8322-8170-3
– 2 – IEC 60034-2-1:2024 © IEC 2024
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Symbols and abbreviated terms . 13
4.1 Symbols . 13
4.2 Additional subscripts . 14
5 Basic requirements . 15
5.1 Direct and indirect efficiency determination . 15
5.2 Uncertainty . 15
5.3 Preferred methods and methods for customer-specific acceptance tests,
field-tests or routine-tests . 15
5.4 Power supply . 16
5.4.1 Voltage . 16
5.4.2 Frequency . 16
5.5 Instrumentation . 16
5.5.1 General . 16
5.5.2 Measuring instruments for electrical quantities . 16
5.5.3 Torque measurement . 16
5.5.4 Speed and frequency measurement . 17
5.5.5 Temperature measurement . 17
5.6 Units . 17
5.7 Resistance . 17
5.7.1 Test resistance . 17
5.7.2 Winding temperature . 18
5.7.3 Correction to reference coolant temperature . 18
5.8 State of the machine under test and test categories . 19
5.9 Excitation circuit measurements . 20
5.10 Ambient temperature during testing . 20
6 Test methods for the determination of the efficiency of induction machines . 20
6.1 Preferred testing methods . 20
6.1.1 General . 20
6.1.2 Method 2-1-1A – Direct measurement of input and output . 21
6.1.3 Method 2-1-1B – Summation of losses, additional load losses according
to the method of residual loss . 23
6.1.4 Method 2-1-1C – Summation of losses with additional load losses from
assigned allowance . 31
6.2 Testing methods for field or routine-testing . 35
6.2.1 General . 35
6.2.2 Method 2-1-1D – Dual supply back-to-back-test . 36
6.2.3 Method 2-1-1E – Single supply back-to-back-test . 37
6.2.4 Method 2-1-1F – Summation of losses with additional load losses
determined by test with rotor removed and reverse rotation test . 38
6.2.5 Method 2-1-1G – Summation of losses with additional load losses
determined by Eh-star method . 42
6.2.6 Method 2-1-1H – Determination of efficiency by use of the equivalent
circuit parameters . 46
7 Test methods for the determination of the efficiency of synchronous machines . 52
7.1 Preferred testing methods . 52
7.1.1 General . 52
7.1.2 Method 2-1-2A – Direct measurement of input and output . 53
7.1.3 Method 2-1-2B – Summation of separate losses with a rated load
temperature test and a short circuit test . 54
7.1.4 Method 2-1-2C – Summation of separate losses without a full load test . 60
7.2 Testing methods for field or routine testing . 62
7.2.1 General . 62
7.2.2 Method 2-1-2D – Dual supply back-to-back-test . 62
7.2.3 Method 2-1-2E – Single supply back-to-back-test . 63
7.2.4 Method 2-1-2F – Zero power factor test with excitation current from
Potier-, ASA- or Swedish-diagram . 65
7.2.5 Method 2-1-2G – Summation of separate losses with a load test without
consideration of additional load losses . 69
8 Test methods for the determination of the efficiency of DC machines . 70
8.1 Testing methods for field or routine testing . 70
8.2 Method 2-1-3A – Direct measurement of input and output . 71
8.2.1 General . 71
8.2.2 Test procedure . 72
8.2.3 Efficiency determination. 72
8.3 Method 2-1-3B – Summation of losses with a load test and DC component of
additional load losses from test . 73
8.3.1 General . 73
8.3.2 Test procedure . 74
8.4 Method 2-1-3C – Summation of losses with a load test and DC component of
additional load losses from assigned value . 80
8.4.1 General . 80
8.4.2 Test procedure . 81
8.4.3 Efficiency determination. 82
8.5 Method 2-1-3D – Summation of losses without a load test . 83
8.5.1 General . 83
8.5.2 Test procedure . 84
8.5.3 Efficiency determination. 85
8.6 Method 2-1-3E – Single supply back-to-back test . 86
8.6.1 General . 86
8.6.2 Test procedure . 86
8.6.3 Efficiency determination. 87
Annex A (normative) Calculation of values for the Eh-star method . 88
Annex B (informative) Types of excitation systems . 91
Annex C (informative) Induction machine slip measurement . 92
Annex D (informative) Test report template for method 2-1-1B . 94
Bibliography . 95
Figure 1 – Torque measuring devices . 17
Figure 2 – Sketch for torque measurement test . 21
Figure 3 – Efficiency determination according to method 2-1-1A . 22
Figure 4 – Efficiency determination according to method 2-1-1B . 24
Figure 5 – Smoothing of the residual loss data . 30
– 4 – IEC 60034-2-1:2024 © IEC 2024
Figure 6 – Efficiency determination according to method 2-1-1C . 32
Figure 7 – Vector diagram for obtaining current vector from reduced voltage test . 33
Figure 8 – Assigned allowance for additional load losses P . 34
LL
Figure 9 – Efficiency determination according to method 2-1-1D . 36
Figure 10 – Sketch for dual supply back-to-back test . 36
Figure 11 – Efficiency determination according to method 2-1-1E . 37
Figure 12 – Efficiency determination according to method 2-1-1F . 39
Figure 13 – Efficiency determination according to method 2-1-1G . 43
Figure 14 – Eh-star test circuit . 44
Figure 15 – Induction machine, T-model with equivalent iron loss resistor . 46
Figure 16 – Efficiency determination according to method 2-1-1H . 47
Figure 17 – Induction machines, reduced model for calculation . 50
Figure 18 – Sketch for torque measurement test . 53
Figure 19 – Efficiency determination according to method 2-1-2A . 53
Figure 20 – Efficiency determination according to method 2-1-2B . 55
Figure 21 – Efficiency determination according to method 2-1-2C . 61
Figure 22 – Efficiency determination according to method 2-1-2D . 62
Figure 23 – Sketch for dual supply back-to-back test ( I If, f ) . 63
M GM G
Figure 24 – Efficiency determination according to method 2-1-2E . 64
Figure 25 – Single supply back-to-back test for synchronous machines . 64
Figure 26 – Efficiency determination according to method 2-1-2F . 65
Figure 27 – Efficiency determination according to method 2-1-2G . 70
Figure 28 – Sketch for torque measurement test . 71
Figure 29 – Efficiency determination according to method 2-1-3A . 72
Figure 30 – Efficiency determination according to method 2-1-3B . 74
Figure 31 – Sketch for single supply back-to-back test for determination of DC
component of additional load losses . 78
Figure 32 – Efficiency determination according to method 2-1-3C . 81
Figure 33 – Efficiency determination according to method 2-1-3D . 84
Figure 34 – Efficiency determination according to method 2-1-3E . 86
Figure 35 – Sketch for single supply back-to-back test . 86
Figure C.1 – Slip measurement system block diagram . 93
Table 1 – Reference temperature . 18
Table 2 – Induction machines: preferred testing methods . 21
Table 3 – Induction machines: other methods . 36
Table 4 – Synchronous machines with electrical excitation: preferred testing methods . 52
Table 5 – Synchronous machines with permanent magnets: preferred testing methods . 52
Table 6 – Synchronous machines: other methods . 62
Table 7 – DC machines: test methods . 71
Table 8 – Multiplying factors for different speed ratios . 82
==
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ROTATING ELECTRICAL MACHINES –
Part 2-1: Standard methods for determining losses and efficiency
from tests (excluding machines for traction vehicles)
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
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preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
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Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 60034-2-1 has been prepared by IEC technical committee 2: Rotating machinery. It is an
International Standard.
This third edition cancels and replaces the second edition of IEC 60034-2-1 published in 2014.
This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
Harmonization of layout and requirements with IEC 60034-2-2 and IEC 60034-2-3.
– 6 – IEC 60034-2-1:2024 © IEC 2024
The text of this International Standard is based on the following documents:
Draft Report on voting
2/2165/FDIS 2/2177/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 60034 series, published under the general title Rotating electrical
machines, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
ROTATING ELECTRICAL MACHINES –
Part 2-1: Standard methods for determining losses and efficiency
from tests (excluding machines for traction vehicles)
1 Scope
This part of IEC 60034 is intended to establish methods of determining efficiencies from tests,
and also to specify methods of obtaining specific losses.
This document applies to DC machines and to AC synchronous and induction machines of all
sizes within the scope of IEC 60034-1 rated for mains operation.
NOTE These methods may be applied to other types of machines such as rotary converters, AC commutator motors
and single-phase induction motors.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60027-1, Letter symbols to be used in electrical technology – Part 1: General
IEC 60034-1:2022, Rotating electrical machines – Part 1: Rating and performance
IEC 60034-4-1:2018, Rotating electrical machines – Part 4-1: Methods for determining
electrically excited synchronous machine quantities from tests
IEC 60034-19, Rotating electrical machines – Part 19:Specific test methods for DC machines
on conventional and rectifier-fed supplies
IEC 60034-29, Rotating electrical machines – Part 29: Equivalent loading and superposition
techniques – Indirect testing to determine temperature rise
IEC 60034-30-1, Rotating electrical machines – Part 30-1: Efficiency classes of line operated
AC motors (IE code)
IEC 60051(all parts), Direct acting indicating analogue electrical measuring instruments and
their accessories
IEC 60051-1, Direct acting indicating analogue electrical measuring instruments and their
accessories – Part 1: Definitions and general requirements common to all parts
– 8 – IEC 60034-2-1:2024 © IEC 2024
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60034-1, IEC 60051-1
and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
efficiency
ratio of output power to input power expressed in the same units and usually given as a
percentage
3.2
direct efficiency determination
method by which the determination of efficiency is made by measuring directly the input power
and the output power
3.3
dual-supply back-to-back test
test in which two identical machines are mechanically coupled together, and the total losses of
both machines are calculated from the difference between the electrical input to one machine
and the electrical output of the other machine
3.4
indirect efficiency determination
method by which the determination of efficiency is made by measuring the input power or the
output power and determining the total losses. Those losses are added to the output power,
thus giving the input power, or subtracted from the input power, thus giving the output power
3.5
single-supply back-to-back test
test in which two identical machines are mechanically coupled together and are both connected
electrically to the same power system. The total losses of both machines are taken as the input
power drawn from the system
3.6
no-load test
test in which a machine is run as a motor providing no useful mechanical output from the shaft,
or if run as a generator with its terminals open-circuited
3.7
zero power factor test
no-load test on a synchronous machine, which is over-excited and operates at a power factor
very close to zero
3.8
equivalent circuit method
test on an induction machine in which the losses are determined by help of an equivalent circuit
model
3.9
test with rotor removed and reverse rotation test
combined test on an induction machine in which the additional load losses are determined from
a test with rotor removed and a test with the rotor running in reverse direction to the rotating
magnetic field of the stator
3.10
short-circuit test
test on a synchronous machine in which a machine is run as a generator with its terminals short-
circuited
3.11
locked rotor test
test in which the rotor is locked to prevent rotation
3.12
Eh-star test
test in which the motor is run in star connection on unbalanced voltage
3.13
losses
3.13.1
total losses
P
T
difference between the input power and the output power, equivalent to the sum of the constant
losses (see 3.13.2), the load losses (see 3.13.4), the additional load losses (see 3.13.5) and
the excitation circuit losses (see 3.13.3)
3.13.2
constant losses
P
c
losses incorporating the sum of windage, friction and iron losses
Note 1 to entry: Although these losses change with voltage and load, they are historically called “constant” losses
and the name is retained in this document.
3.13.2.1
iron losses
P
fe
losses in active iron and additional no-load losses in other magnetic and conductive parts
3.13.2.2
friction and windage losses
P
fw
losses incorporating the sum of windage and friction
3.13.2.2.1
friction losses
losses due to friction (bearings and brushes, if not lifted at rated conditions) not including any
losses in a separate lubricating system
– 10 – IEC 60034-2-1:2024 © IEC 2024
3.13.2.2.2
windage losses
total losses due to aerodynamic friction in all parts of the machine, including power absorbed
in shaft mounted fans, and in auxiliary machines forming an integral part of the machine
Note 1 to entry: Losses in a separate ventilating system should be listed separately.
Note 2 to entry: For machines indirectly or directly cooled by hydrogen, see IEC 60034-1.
3.13.3
excitation circuit losses
3.13.3.1
excitation circuit losses
P
e
sum of the excitation winding losses (see 3.13.3.2), the exciter losses (see 3.13.3.3) and, for
synchronous machines, electrical brush loss (see 3.13.3.5), if any
3.13.3.2
excitation winding losses
P
f
excitation (field) winding losses are equal to the product of the exciting current I and the
e
excitation voltage U
e
3.13.3.3
exciter losses
P
Ed
exciter losses for the different excitation systems (see Annex B) are defined as follows:
a) shaft driven exciter
exciter losses are the power absorbed by the exciter at its shaft (reduced by friction and
windage losses) plus the power P drawn from a separate source at its excitation winding
1E
terminals, minus the useful power which the exciter provides at its terminals. The useful
power at the terminals of the exciter is equal to the excitation winding losses as per 3.13.3.2
plus (in the case of a synchronous machine) the electrical brush losses as per 3.13.3.5.
Note 1 to entry: If the exciter can be decoupled and tested separately its losses can be determined according
to 7.1.3.2.1.5.
Note 2 to entry: Whenever the exciter makes use of separate auxiliary supplies, their consumptions are to be
included in the exciter losses unless they are considered together with the main machine auxiliaries consumption.
b) brushless exciter
exciter losses are the power absorbed by the exciter at its shaft, reduced by friction and
windage losses (when the relevant test is performed on the set of main machine and exciter),
plus the electrical power P from a separate source (if any) absorbed by its field winding
1E
or its stator winding (in the case of an induction exciter), minus the useful power which the
exciter provides at the rotating power converter terminals.
Note 3 to entry: Whenever the exciter makes use of separate auxiliary supplies their consumptions are to be
included in the exciter losses unless they are considered together with the main machine auxiliaries consumption.
Note 4 to entry: If the exciter can be decoupled and tested separately, its losses can be determined according
to 7.1.3.2.1.
c) separate rotating exciter
exciter losses are the difference between the power absorbed by the driving motor, plus the
power absorbed by separate auxiliary supplies, of both driving and driven machines,
including the power supplied by separate source to their excitation winding terminals, and
the excitation power supplied as per 3.13.3.2 and 3.13.3.4. The exciter losses may be
determined according to 7.1.3.2.1.
d) static excitation system
static exciter
excitation system losses are the difference between the electrical power drawn from its
power source, plus the power absorbed by separate auxiliary supplies, and the excitation
supplied as per 3.13.3.2 and 3.13.3.4.
Note 5 to entry: In the case of systems fed by transformers, the transformer losses shall be included in the
exciter losses.
e) excitation from auxiliary winding
auxiliary winding exciter
exciter losses are the copper losses in the auxiliary (secondary) winding and the additional
iron losses produced by increased flux harmonics. The additional iron losses are the
difference between the losses which occur when the auxiliary winding is loaded and when
it is unloaded.
Note 6 to entry: Because separation of the excitation component of losses is difficult, it is recommended to
consider these losses as an integral part of the stator losses when determining overall losses.
In the cases c) and d) no allowance is made for the losses in the excitation source (if any)
or in the connections between the source and the brushes (synchronous machine) or
between the source and the excitation winding terminals (DC machine).
If the excitation is supplied by a system having components as described in b) to e) the
exciter losses shall include the relevant losses of the components pertaining to the
categories listed in Annex B as applicable.
3.13.3.4
separately supplied excitation power
P
1E
excitation power P supplied from a separate power source is:
1E
– for exciter types a) and b) the exciter excitation power (DC or synchronous exciter) or stator
winding input power (induction exciter). It covers a part of the exciter losses P (and further
Ed
losses in induction exciters) while a larger part of P is supplied via the shaft;
e
– for exciter types c) and d) equal to the excitation circuit losses, P = P ;
1E e
– for exciter type e) P = 0, the excitation power being delivered entirely by the shaft. Also,
1E
P = 0 for machines with permanent magnet excitation.
1E
Exciter types shall be in accordance with 3.13.3.3.
3.13.3.5
brush losses (excitation circuit)
P
b
electrical brush loss (including contact loss) of separately excited synchronous machines
3.13.4
load losses
3.13.4.1
load losses
P
L
sum of the winding (I R) losses (see 3.13.4.2) and the electrical brush losses (see 3.13.3.5), if
any
– 12 – IEC 60034-2-1:2024 © IEC 2024
3.13.4.2
winding losses
winding losses are I R losses:
– in the armature circuit of DC machines;
– in the stator and rotor windings of induction machines;
– in the armature and field windings of synchronous machines
3.13.4.3
brush losses
P
b
electrical brush loss (including contact loss) in the armature circuit of DC machines and in
wound-rotor induction machines
3.13.5
additional load losses
P
LL
losses produced in active iron and other magnetic and conductive parts by alternating stray
fluxes when the machine is loaded; eddy current losses in winding conductors caused by load
current-dependent flux pulsations and additional brush losses caused by commutation
Note 1 to entry: These losses do not include the additional no-load losses of 3.13.2.2.
3.13.6
short-circuit losses
P
sc
current-dependent losses in a synchronous machine and in a DC machine when the armature
winding is short-circuited
3.14
test quantities
3.14.1
terminal voltage
for polyphase AC machines, the arithmetic average of line voltages
3.14.2
line current
for polyphase AC machines, the arithmetic average of line currents
3.14.3
line-to-line resistance
for polyphase AC machines, the arithmetic average of resistances measured between each pair
of terminals
Note 1 to entry: For Y-connected three-phase machines, the phase-resistance is 0,5 times the line-to-line
resistance. For Δ-connected machines, the phase-resistance is 1,5 times the line-to-line resistance.
Note 2 to entry: In Clauses 6 and 7 explanations and formulae given are for three-phase machines, unless otherwise
indicated.
3.14.4
temperature rise
is the machine temperature minus the cooling medium (coolant) temperature as defined by
IEC 60034-1
4 Symbols and abbreviated terms
4.1 Symbols
cos φ is the power factor
f is the supply frequency, Hz
I is the line current (average of all phases), A
k is the temperature correction factor
θ
–1
n is the operating speed, s
p is the number of pole pairs
P is the power, W
P is the input power at no-load, W
P is the input power, excluding excitation , W
P is the output power, W
P is the brush loss, W
b
P is the output power (shaft power) of a drive motor, W
D
P is the excitation circuit losses, W
e
P is the excitation power supplied by a separate source, W
1E
P is the exciter losses, W
Ed
is the electrical power, excluding excitation, W
P
el
P is the excitation (field) winding losses, W
f
P is the iron losses, W
fe
P is the friction and windage losses, W
fw
P is the constant losses, W
c
P is the load losses, W
L
P is the residual losses, W
Lr
P is the additional-load losses, W
LL
P is the short-circuit losses, W
sc
P is the mechanical power, W
mech
P is the total losses, W
T
P is the winding losses, W, where subscript w is generally replaced by a, f,
w
e, s or r (see 4.2)
R is a winding resistance, Ω
R is the actual value of the auxiliary resistor for the Eh-star test (see 6.2.5),
eh
Ω
R’ is the typical value of the auxiliary resistor, Ω
eh
R is the field winding resistance, Ω
f
___________
This definition assumes sinusoidal voltage and current.
Unless otherwise indicated, the tests in this document are described for motor operation, where P and P are
1 2
electrical input and mechanical output power, respectively.
– 14 – IEC 60034-2-1:2024 © IEC 2024
R is the line-to-line-resistance (average of all phases), Ω
II
R is the phase-resistance (average of all phases), Ω
ph
s is the slip, in per unit value of synchronous speed
T is the machine torque, N·m
T is the reading of the torque measuring device, N·m
d
U is the terminal voltage (average of all phases), V
U is the terminal voltage at no-load (average of all phases), V
U is the rated terminal voltage, V
N
X is the reactance, Ω
Z= R+×jX is the notation for a complex quantity (impedance as example)
ZZ R+ X is the absolute value of a complex quantity (impedance as example)
Z is the impedance, Ω
𝛼𝛼 is a temperature coefficient
η is the efficiency
θ is the initial winding temperature, °C
θ is the ambient temperature, °C
a
θ primary coolant inlet temperature, °C
c
θ is the winding temperature, °C
w
τ is a time constant, s
4.2 Additional subscripts
The following subscripts may be added to symbols to clarify the machine function and to
differentiate values.
Machine components:
a armature
e excitation
f field winding
r rotor
s stator
w winding
U,V,W phase designations
Machine categories:
B booster
E exciter
G generator
M motor
==
Operating conditions:
0 no-load
1 input
2 output
av average, mean
d dissipated
el electrical
i internal
sc short circuit
L test load
lr locked rotor
mech mechanical
N rated
red at reduced voltage
t test
zpf zero power factor test
θ corrected to a reference coolant temperature.
NOTE Further additional subscripts are introduced in relevant subclauses.
5 Basic requirements
5.1 Direct and indirect efficiency determination
Tests can be grouped into the three following categories:
a) input-output power measurement on a single machine. This involves the direct measurement
of electrical or mechanical power into, and mechanical or electrical power out of a machine;
b) electrical input and output measurement on two identical machines mechanically connected
back-to-back. This is done to eliminate the measurement of mechanical power into or out of
the machine;
c) determination of the actual loss in a machine under a particular condition. This is usually
not the total loss but comprises certain loss components.
The methods for determining the efficiency of machines are based on a number of assumptions.
Therefore, it is not recommended that a comparison be made between the values of efficiency
obtained by different methods, because the figures may not necessarily agree.
5.2 Uncertainty
Uncertainty as used in this standard is the uncertainty of determining a true efficiency. It reflects
...
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