IEC 60034-2-1:2007

IEC 60034-2-1
Edition 1.0 2007-09
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 1.0 2007-09
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
PRICE CODE
INTERNATIONALE
XB
CODE PRIX
ICS 29.160 ISBN 2-8318-9250-3
– 2 – 60034-2-1 © IEC:2007
CONTENTS
FOREWORD.4

INTRODUCTION.6

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.16
5.4 Power supply.20
5.5 Instrumentation.20
5.6 Units .21
5.7 Resistance .21
6 Test methods for determination of efficiency .22
6.1 State of the machine under test and test categories .22
6.2 Excitation circuit measurements.23
6.3 Direct measurements.23
6.4 Indirect measurements .25
7 Determination of efficiency (direct current machines) .37
7.1 Determination from direct measurement.37
7.2 Determination from indirect measurement.37
8 Determination of efficiency (induction machines) .42
8.1 Determination from direct measurement.42
8.2 Determination from indirect measurement.43
9 Determination of efficiency (synchronous machines) .54
9.1 Determination from direct measurement.54
9.2 Determination from indirect measurement.55

Annex A (normative) Correction of dynamometer torque readings .61
Annex B (normative) Calculation of values for the Eh-star method .63
Annex C (informative) Types of excitation systems .66
Annex D (normative) Other test methods .67

60034-2-1 © IEC:2007 – 3 –
Figure 1 – Sketch for torque measurement test .24

Figure 2 – Sketch for dual supply back-to-back test (for synchronous machines:

I==If, f ) .24
MG M G
Figure 3 – Sketch for single supply back-to-back test, d.c. machines .26

Figure 4 – Sketch for single supply back-to-back test, synchronous machines .27

Figure 5 – Induction machine, T-model with equivalent iron loss resistor.31

Figure 6 – Sketch for single supply back-to-back, additional losses, d.c. machines .32

Figure 7 – Eh-star test circuit .35
Figure 8 – Vector diagram for obtaining current vector from reduced voltage test.46
Figure 9 – Induction machines, Reduced model for calculation .49
Figure 10 – Smoothing of the residual loss data.51
Figure 11 – Assigned allowance for additional load losses P , induction machines.53
LL
Table 1 – DC machines .17
Table 2 – Induction machines.18
Table 3 – Synchronous machines .19
Table 4 – Reference temperature .22
Table 5 – Multiplying factors for different speed ratios .42

– 4 – 60034-2-1 © IEC:2007
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
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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) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60034-2-1 has been prepared by IEC technical committee 2:
Rotating machinery.
This standard cancels and replaces IEC 60034-2 (1972), its amendment 1 (1995) and its
amendment 2 (1996). IEC 60034-2A (1974) is retained for the time being.
The text of this standard is based on the following documents:
FDIS Report on voting
2/1443/FDIS 2/1460/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.

60034-2-1 © IEC:2007 – 5 –
A list of all parts of IEC 60034 series, under the general title Rotating electrical machines, can

be found on the IEC website.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

The committee has decided that the contents of this publication will remain unchanged until the

maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the data

related to the specific publication. At this date, the publication will be

• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – 60034-2-1 © IEC:2007
INTRODUCTION
During the revision phase for IEC 60034-2: 1972 and its amendments IEC 60034-2 A1: 1995

(defining IEC 60034-2A: 1974 as Clause 17) and IEC 60034-2 A2: 1996, WG 28 proposed and

TC 2 agreed to separate the revised standard into three sections:

– the first part (IEC 60034-2-1) to cover machines within the scope of IEC 60034-1, which

are normally tested under load;

– the second part (IEC 60034-2-2) to cover tests applicable mainly for large machines

where the facility cost for other methods is not economical (especially the calibrated-

machine test, the retardation test and the calorimetric method);

– the third part (IEC 60034-2-3) for tests on machines for converter supply.
To retain in IEC 60034-2-1 as normative the test methods that will eventually become
IEC 60034-2-2, a temporary Annex D has been added. This annex contains elements from
IEC 60034-2:1972 and its amendment 1:1995. It also makes reference to IEC 60034-2A:1974.
Both will be incorporated in the future IEC 60034-2-2.

60034-2-1 © IEC:2007 – 7 –
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 standard applies to d.c. machines and to a.c. synchronous and induction machines of all
sizes within the scope of IEC 60034-1.
NOTE These methods may be applied to other types of machines such as rotary converters, a.c. commutator
motors and single-phase induction motors.
2 Normative references
The following referenced documents are indispensable for the application 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, Rotating electrical machines – Part 1: Rating and performance
IEC 60034-2A, Rotating electrical machines – Part 2: Methods for determining losses and
efficiency of rotating electrical machinery form tests (excluding machines for traction vehicles)
– First supplement: Measurement of losses by the calorimetric method
IEC 60034-4, Rotating electrical machines – Part 4: Methods for determining synchronous
machine quantities from tests
IEC 60034-19, Rotating electrical machines – Part 19:Specific test methods for d.c. machines
on conventional and rectifier-fed supplies

IEC 60044 (all parts), Instrument transformers
IEC 60051-1, Direct acting indicating analogue electrical measuring instruments and their
accessories – Part 1: Definitions and general requirements common to all parts
IEC 61986, Rotating electrical machines – Equivalent loading and super-position techniques –
Indirect testing to determine temperature rise
NOTE A revision of IEC 61986 is under consideration; it will be published under reference IEC 60034-29.

– 8 – 60034-2-1 © IEC:2007
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 definitions apply.

3.1
efficiency
ratio of output power to input power expressed in the same units and usually given as a

percentage
3.2 Tests for direct efficiency determination
3.2.1
general
method by which the direct determination of efficiency is made by measuring directly the input
power and the output power
3.2.2
torque meter test
test in which the mechanical power output of a machine acting as a motor is determined by
measurement of the shaft torque by means of a torque meter together with the rotational
speed. Alternatively, a test performed on a machine acting as a generator, by means of a
torque meter to determine the mechanical power input
3.2.3
dynamometer test
test in accordance with 3.2.2 but measuring the shaft torque by means of a dynamometer
3.2.4
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
3.3 Tests for indirect efficiency determination
3.3.1
general
test in which the indirect 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

3.3.2
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
3.3.3
no-load test
test in which a machine run as a motor provides no useful mechanical output from the shaft, or
when run as a generator with its terminals open-circuited

60034-2-1 © IEC:2007 – 9 –
3.3.4
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
3.3.5
equivalent circuit method (induction machines)

test in which the losses are determined by help of an equivalent circuit model

3.3.6
test with rotor removed and reverse rotation test (induction machines)

combined test 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
3.3.7
short-circuit test (synchronous machines)
test in which a machine is run as a generator with its terminals short-circuited
3.3.8
locked rotor test
test in which the rotor is locked to prevent rotation
3.3.9
eh-star test
test in which the motor is run in star connection on unbalanced voltage.
3.4 Losses
3.4.1
total losses P
T
difference between the input power and the output power, equivalent to the sum of the constant
losses (see 3.4.2), the load losses (see 3.4.4), the addititional load losses (see 3.4.5) and the
excitation circuit losses (see 3.4.3)
3.4.2 Constant losses
3.4.2.1
constant losses P
k
sum of the iron losses and the friction and windage losses
3.4.2.2
iron losses P
fe
losses in active iron and additional no-load losses in other metal parts
3.4.2.3 Friction and windage losses P
fw
3.4.2.3.1
friction losses
losses due to friction (bearings and brushes, if not lifted at rated conditions) not including any
losses in a separate lubricating system. Losses in common bearings should be stated
separately, whether or not such bearings are supplied with the machine. The bearing losses
are based on the operating temperatures of the bearings, the type of oil and oil temperature.
NOTE 1 When the losses in a separate lubricating system are required these should be listed separately.

– 10 – 60034-2-1 © IEC:2007
For vertical machines, the losses in thrust bearings shall be determined excluding any external
thrust.
NOTE 2 Additional losses due to external thrust may be stated separately by agreement, which should then

include thrust load, temperature of the bearings, type of oil and also oil temperature.

NOTE 3 Friction losses due to thrust load may be included by agreement.

If the tested machine uses direct flow cooling of the bearings, these losses are distributed

between the tested machine and any other one coupled to it mechanically, such as a turbine, in

proportion to the masses of their rotating parts. If there is no direct flow cooling, the distribution

of bearing losses shall be determined from empirical formulae by agreement

3.4.2.3.2
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 Losses in a separate ventilating system should be listed separately.
NOTE 2 For machines indirectly or directly cooled by hydrogen, see IEC 60034-1.
3.4.3 Excitation circuit losses
3.4.3.1
excitation circuit losses P
e
sum of the excitation winding losses (see 3.4.3.2), the exciter losses (see 3.4.3.3) and, for
synchronous machines, electrical brush loss (see 3.4.3.5), if any
3.4.3.2
excitation winding losses P
f
the excitation (field) winding losses are equal to the product of the exciting current I and the
e
excitation voltage U
e
3.4.3.3
exciter losses P
Ed
the exciter losses for the different excitation systems (see Annex C) are defined as follows:
a) Shaft driven exciter
The 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
1E
winding 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

3.4.3.2 plus (in the case of a synchronous machine) the electrical brush losses as per
3.4.3.5.
the exc
If iter can be decoupled and tested separately its losses can be determined
according to 5.3.
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.
60034-2-1 © IEC:2007 – 11 –
b) Brushless exciter
The 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
1E
winding 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.

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.
If the exciter can be decoupled and tested separately, its losses can be determined

according to 5.3.
c) Separate rotating exciter
The 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 3.4.3.2 and 3.4.3.4. The exciter losses
may be determined according to 5.3.
d) Static excitation system (static exciter)
The 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 3.4.3.2 and 3.4.3.4.
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)
The 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.
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 (d.c. 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 C as applicable.
3.4.3.4
separately supplied excitation power P
1E
the excitation power P supplied from a separate power source is:
1E
– for exciter types a) and b) the exciter excitation power (d.c. or synchronous exciter) or
(and
stator winding input power (induction exciter). It covers a part of the exciter losses P
Ed
further losses in induction exciters) while a larger part of P is supplied via the shaft;
e
– 12 – 60034-2-1 © IEC:2007
– 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
= 0 for machines with permanent magnet excitation.
P
1E
Exciter types shall be in accordance with 3.4.3.3

3.4.3.5
brush losses P (excitation circuit)
b
electrical brush loss (including contact loss) of separately excited synchronous machines

3.4.4 Load losses
3.4.4.1
load losses P
L
the sum of the winding (I R) losses (see 3.4.4.2) and the electrical brush losses (see 3.4.4.3),
if any
3.4.4.2
winding losses
winding losses are I R losses:
– in the armature circuit of d.c. machines;
– in the stator and rotor windings of induction machines;
– in the armature windings of synchronous machines
3.4.4.3
brush losses P (load circuits)
b
electrical brush loss (including contact loss) in the armature circuit of d.c. machines and in
wound-rotor induction machines
3.4.5
additional load losses P (stray-load losses)
LL
losses produced by the load current in active iron and other metal parts other than conductors;
eddy current losses in winding conductors caused by load current-dependent flux pulsations
and additional brush losses caused by commutation
NOTE These losses do not include the additional no-load losses of 3.4.2.2.
3.4.6
short-circuit losses P
sc
current-dependent losses in a synchronous machine and in a d.c. machine when the armature

winding is short-circuited
3.5 Test quantities (polyphase a.c. machines)
3.5.1
terminal voltage
for polyphase a.c. machines the arithmetic average of line voltages
3.5.2
line current
for polyphase a.c. machines the arithmetic average of line currents

60034-2-1 © IEC:2007 – 13 –
3.5.3
line-to-line resistance
for polyphase a.c. machines, the arithmetic average of line-to-line resistance across each set

of terminals
NOTE 1 For Y-connected three-phase machines, the phase-resistance is 0,5 line-to-line resistance. For Δ-

connected machines, the phase-resistance is 1,5 line-to-line resistance.

NOTE 2 In Clauses 7, 8 and 9, explanations and equations given are for three-phase machines, unless otherwise
indicated.
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, 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 excitation circuit losses, W
e
P is the excitation power supplied by a separate source, W
1E
P is the exciter losses, W
Ed
P is the electrical power, excluding excitation, W
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 mechanical power, W
mech
P  is the short-circuit losses, W
k
P is the total losses, W
T
P is the winding losses, W,
w
where subscript w is generally replaced by a, f, e, s or r
___________
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 – 60034-2-1 © IEC:2007
R is a winding resistance, Ω
R is the actual value of the auxiliary resistor used for the Eh-star test (see 6.4.5.5), Ω
eh
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, Ω
II
R is the average phase-resistance, 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, V
U is the terminal voltage at no-load, V
U is the rated terminal voltage, V
N
X is the reactance, Ω
Z=+Rj×X is the notation for a complex quantity (impedance as example)
Z==ZR+X is the absolute value of a complex quantity (impedance as example)
Z is the impedance, Ω
η is the efficiency
is the initial winding temperature, ºC
θ
θ is the ambient temperature, ºC
a
θ primary coolant inlet temperature, ºC
c
θ is the winding temperature, ºC
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
60034-2-1 © IEC:2007 – 15 –
Operating conditions:
0 no-load
1 input
2 output
av average, mean
d dissipated
el electrical
i internal
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 measurement on a single machine. This involves the measurement of
electrical or mechanical power into, and mechanical or electrical power out of a machine;
b) 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) measurement of the actual loss in a machine under a particular condition. This is not
usually the total loss but comprises certain loss components. The method may, however,
be used to calculate the total loss or to calculate a loss component.
The determination of total losses shall be carried out by one of the following methods:

– measurement of total losses;
– determination of separate losses for summation;
NOTE The methods for determining the efficiency of machines are based on a number of assumptions. Therefore,
it is not possible to make a comparison between the values of efficiency obtained by different methods.
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 be expressed as a numerical value, such a requirement needs
sufficient testing to determine representative and comparative values. This standard uses the
following relative uncertainty terms:

– 16 – 60034-2-1 © IEC:2007
– "low" applies to efficiency determinations based solely upon test results;

– "medium" applies to efficiency determinations based upon limited approximations;

– "high" applies to efficiency determinations based upon assumptions.

5.3 Preferred methods
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).

Preferred methods are given for each machine configuration in Tables 1 to 3. The test method

should be selected from the procedures with the lowest uncertainty.

60034-2-1 © IEC:2007 – 17 –
Table 1 – DC machines
Method Clause Preferred method Required facilities Uncertainty

Direct
Calibrated machine test Annex D Calibrated machine See Note 3

Machine size: Torquemeter/dynamometer

Torque measurement 7.1.1 Low
H ≤ 180 for full-load
Total losses
Single-supply, back-to-back Two identical units
7.2.1.1 Low
test Booster generator
Summation of losses,
with load test
P d.c. component: single Two ident
LL ical units
7.2.2.6.1 Low
supply back-to-back test Booster generator
P d.c. component from
LL
7.2.2.6.3  Medium
assigned value
P a.c. component from Machine size:
LL
7.2.2.6.2 Specified rectifier Low
specified rectifier supply H > 180
Summation of losses, without load test
Excitation loss from an If test equipment for other
assigned ratio of load to no- tests is not available (no
7.2.2.5 High
load excitation current
possibility of loading, no
P from assigned value duplicate machine)
LL
NOTE 1 Due to instrumentation inaccuracies the direct test method is limited to efficiencies up to 95 % to 96 %.
For practical purposes, this standard recommends direct tests for machines up to shaft height 180 mm since these
are not likely to exceed 95 % efficiency. Machines of larger size and efficiencies below 95 % to 96 % may also be
tested successfully using the direct test method.
NOTE 2 In the "Uncertainty" column, “Low” indicates a procedure determining all loss-components from tests;
“Medium” indicates a procedure which is based on a simplified physical model of the machine; “High” indicates a
procedure that does not determine all loss-components by tests.
NOTE 3 Uncertainty to be determined.

– 18 – 60034-2-1 © IEC:2007
Table 2 – Induction machines
Method Clause Preferred method Required facilities Uncertainty

Direct
All single phase
Torquemeter/dynamometer for
Torque measurement 8.1.1 and polyphase Low
full-load
≤ 1 kW
Calibrated machine test Annex D Calibrated machine See Note 4

Dual-supply, back-to-back Machine set for full-load
8.1.2 Low
test Two identical units
Total losses
Calorimetric method Annex D Special thermal enclosure See Note 4
Single supply back-to-back Two identical units (wound
8.2.1 Low
test rotor)
Summation of losses,
with and without load test
Three phase
P determined from residual Torquemeter/dynamometer for
LL
8.2.2.5.1 > 1 kW up to Low
loss ≥ 1,25 × full-load
150 kW
P from assigned value 8.2.2.5.3  Medium to high
LL
P from removed rotor and Auxiliary motor with rated
LL
8.2.2.5.2 High
reverse rotation test power ≤ 5 × total losses P
T
Resistor for 150 % rated
P from Eh-star test 8.2.2.5.4 (see Note 3) Medium
LL
phase current
Summation of losses,
without load test
Currents, powers and slip If test equipment for other
from the equivalent circuit tests is not available (no
Medium/high
8.2.2.4.3
method possibility of applying rated
P from assigned value load, no duplicate machine)
LL
NOTE 1 Due to measurement inaccuracies, the determination of P from residual losses is limited to correlation
LL
coefficients (see 8.2.2.5.1.2) greater than 0,95 and may have uncertainties of the determined efficiency exceeding
±0,5 %.
NOTE 2 In the "Uncertainty" column, “Low” indicates a procedure determining all loss-components from tests;
“Medium” indicates a procedure which is based on a simplified physical model of the machine; “High” indicates a
procedure that does not determine all loss-components by tests.
NOTE 3 The method for P from Eh-star test is suitable for motors between 1 kW and 150 kW; larger ratings are
LL
under consideration. The method requires that the winding can be connected in star.
NOTE 4 Uncertainty to be determined.

60034-2-1 © IEC:2007 – 19 –
Table 3 – Synchronous machines

Method Clause Preferred method Required facilities Uncertainty

Direct
Machine size: Torquemeter/dynamometer for
Torque measurement 9.1.1 Low
H ≤ 180 full-load
Calibrated machine test Annex D Calibrated machine See Note 3

Dual-supply, back-to-back
9.1.2 Two identical units Medium
test
Total losses
Zero power factor with
Supply for full voltage and
excitation current from 9.2.1.2 Medium
current
Potier/ASA/Swedish diagram
Calorimetric method Annex D Special thermal enclosure See Note 3
Single supply back-to-back
9.2.1.1 Two identical units Low
test
Summation of losses,
with load test
Summation except P 9.2.1 Machine set for full-load High
LL
Machine size
P from short-circuit test 9.2.2.6 Low
LL
H > 180
Summation of losses,
without load test
If test equipment for other
Excitation current from 9.2.2.4
tests is not available (no
Potier/ASA/Swedish diagram  Medium
possibility of applying rated
P from short-circuit test 9.2.2.6
LL
load, no duplicate machine)
NOTE 1 Due to instrumentation inaccuracies, the direct test method is limited to efficiencies up to 95 % to 96 %.
For practical purposes, this standard recommends direct tests for machines up to shaft heights of 180 mm since
these are not likely to exceed 95 % efficiency. Machines of larger size and efficiencies below 95 % to 96 % may also
be tested successfully using the direct test method.
NOTE 2 In the "Uncertainty" column, “Low” indicates a procedure determining all loss-components from tests;
“Medium” indicates a procedure which is based on a simplified physical model of the machine; “High” indicates a
procedure that does not determine all loss-components by tests.
NOTE 3 Uncertainty to be determined.

NOTE In the tables, H is the shaft height (distance from the centre line of the shaft to the bottom of the feet), in
millimetres (see frame numbers in IEC 60072-1).

– 20 – 60034-2-1 © IEC:2007
5.4 Power supply
5.4.1 Voltage
The voltage shall be in accordance with 7.2 (and 8.3.1 for thermal tests) of

IEC 60034-1.
5.4.2 Frequency
The frequency shall be within ±0,3 % of the rated frequency during measurements.

NOTE This requirement does not apply for the equivalent-circuit method (6.4.4.4).
5.5 Instrumentation
5.5.1 General
Since instrument accuracy is generally expressed as a percentage of full scale, the range of
the instruments chosen shall be as small as practical.
NOTE For analog instruments the observed values should be in the upper third of the instrument range.
5.5.2 Measuring instruments for electrical quantities
The measuring instruments shall have an accuracy class of 0,2 in accordance with IEC 60051.
NOTE For a routine test as described in 9.1 of IEC 60034-1, an accuracy class of 0,5 is sufficient.
Unless otherwise stated in this standard, the arithmetic average of the three line currents and
voltages shall be used.
5.5.3 Instrument transformers
Instrument transformers shall have an accuracy according to IEC 60044-1 so that the errors of
the instrument transformers are not greater than ±0,5 % for general testing or not greater tha
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