IEC 60034-14:2026

IEC 60034-14 ®
Edition 5.0 2026-11
INTERNATIONAL
STANDARD
COMMENTED VERSION
Rotating electrical machines -
Part 14: Mechanical vibration of certain machines with shaft heights 56 mm and
higher - Measurement, evaluation and limits of vibration severity
ICS 29.160.01 ISBN 978-2-8327-1618-2
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CONTENTS
FOREWORD . 3
1 Scope . 1
2 Normative references . 5
3 Terms and definitions . 5
4 Measurement quantities . 6
4.1 General . 6
4.2 Vibration magnitude . 6
4.3 Relative shaft vibration . 6
5 Measurement equipment . 6
6 Machine mounting . 7
6.1 General . 7
6.2 Free suspension . 7
6.3 Rigid mounting . 7
6.3.1 Foundation . 7
6.3.2 Horizontal machines . 8
6.3.3 Vertical machines . 8
6.4 Active environment determination . 9
7 Conditions of measurement . 9
7.1 Key . 9
7.2 Measurement positions and directions . 9
7.2.1 Measurement positions for vibration . 9
7.2.2 Measurement positions for relative shaft displacement . 10
7.3 Test conditions . 10
7.3.1 Direct-on-line . 10
7.3.2 Variable speed . 10
7.4 Vibration transducer . 10
8 Limits of bearing housing vibration . 11
8.1 Limits of vibration magnitude . 11
8.2 Limits of vibration velocity with twice-line frequency for AC machines . 12
8.3 Axial vibration . 12
9 Limits of relative shaft vibration . 12
Bibliography . 18

Figure 1 – Minimum elastic displacement as a function of rated speed. 14
Figure 2 – Preferred positions of measurement applicable to one or both ends of the
machine . 15
Figure 3 – Measurement positions for those ends of machines where measurements
according to Figure 2 are not possible without disassembly of parts . 15
Figure 4 – Measurement positions for pedestal bearing . 16
Figure 5 – Preferred circumferential position of transducers for the measurement of
relative shaft displacement . 16
Figure 6 – Measurement positions for vertical machines (measurements to be made
at the bearing housing; when not accessible, then as close as possible) . 17
Figure 7 – Vibration limit diagram for shaft heights H > 132 mm. 17

Table 1 – Limits of maximum vibration magnitude in displacement (RMS) and
velocity (RMS) for shaft height H . 11
Table 2 – Limits for the maximum shaft vibration (S ) and the maximum run-out . 13
p-p
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Rotating electrical machines -
Part 14: Mechanical vibration of certain machines
with shaft heights 56 mm and higher -
Measurement, evaluation and limits of vibration severity

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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shall not be held responsible for identifying any or all such patent rights.
This commented version (CMV) of the official standard IEC 60034-14:2026 edition 5.0 allows
the user to identify the changes made to the previous IEC 60034-14:2018 edition 4.0.
Furthermore, comments from IEC TC 2 experts are provided to explain the reasons of the most
relevant changes, or to clarify any part of the content.
A vertical bar appears in the margin wherever a change has been made. Additions are shown
in green text, and deletions in red text with strikethrough. Hover over the comment icons to
display pop-up notes containing the comments, which are also available in the margin of the
publication.
This publication contains the CMV and the official standard.

IEC 60034-14 has been prepared by IEC technical committee 2: Rotating machinery. It is an
International Standard.
This fifth edition cancels and replaces the fourth edition published in 2018. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) subclause 6.3.3 Vertical machines: added two new subclauses: Type and routine tests;
b) subclause 7.3 Test conditions: added two new subclauses: Direct-on-line and variable
speed;
c) Table 1: decreased limits for Grade A in free suspension for 56 ≤ H ≤ 132 mm;
d) Clause 9 Limits of relative shaft vibration: added information how to mitigate effects of run -
out on shaft vibration measurements.
The text of this International Standard is based on the following documents:
Draft Report on voting
2/2323/FDIS 2/2329/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.
NOTE A table of cross-references of all IEC TC 2 publications can be found in the IEC TC 2 dashboard 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.
1 Scope
This part of IEC 60034 specifies the factory acceptance vibration test procedures and vibration
limits for certain electrical machines under specified conditions, when uncoupled from any load
or prime mover.
It is applicable to DC and three-phase AC machines, with shaft heights 56 mm and higher and
–1
a rated output up to 50 MW, at operational speeds from 120 min up to and including
–1
15 000 min .
This document is not applicable to machines mounted in situ (on site), three-phase commutator
motors, single-phase machines, three-phase machines operated on single-phase systems,
vertical waterpower generators, turbine generators greater than 20 MW and machines with
magnetic bearings or series-wound machines.
NOTE 1 For machines measured in situ, refer to applicable clauses or subclauses of ISO 20816, ISO 10816 and
ISO 7919 ISO 20816-1 and ISO 20816-3.
NOTE 2 For output power above 50 MW reference is made to the ISO 20816 series.
NOTE 3 Vibration routine tests are not mandatory according to IEC 60034-1. If performed, the method for testing
is included in this document.
2 Normative references
The following documents are referred to in the text in such a way that some or all 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 60034-1, Rotating electrical machines - Part 1: Rating and performance
IEC 60034-7, Rotating electrical machines – Part 7: Classification of types of constructions and
mounting arrangements (IM Code)
ISO 2954, Mechanical vibration of rotating and reciprocating machinery - Requirements for
instruments for measuring vibration severity
ISO 10817-1, Rotating shaft vibration measuring systems - Part 1: Relative and absolute
sensing of radial vibration from rotating shafts
ISO 20816-1, Mechanical vibration - Measurement and evaluation of machine vibration - Part 1:
General guidelines
ISO 21940-32, Mechanical vibration - Rotor balancing - Part 32: Shaft and fitment key
convention
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60034-1 apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
– IEC Electropedia: available at https://www.electropedia.org/
– ISO Online browsing platform: available at https://www.iso.org/obp
4 Measurement quantities
4.1 General
Measurement quantities are the vibration displacement and vibration velocity at the machine
bearings and the relative shaft vibration displacement within or near the machine bearings.
4.2 Vibration magnitude
The criterion for the vibration magnitude measured at the machine bearings shall be the
broadband RMS value of the vibration displacement in micrometers or the vibration velocity in
millimeters per second in the frequency range specified in Clause 5. The maximum value,
determined at the specified measurement positions and specified measuring variable, according
to this document, characterizes the vibration magnitude of the machine.
Induction motors (especially of two-pole type) frequently show vibration beating at twice slip
frequency. In these cases, the decisive vibration magnitude shall be determined from the
relationship:
xx+
max min
x =
RMS
where
x is the maximum RMS value of vibration displacement or vibration velocity;
max
x is the minimum RMS value of vibration displacement or vibration velocity.
min
The chosen sample rate shall be large enough to reliably capture the maximum and minimum
values of the vibration.
NOTE Large AC induction machines running at very low slip values at no load may can require several minutes to
more than ten minutes for such measurements to be completed at each vibration measuring position.
4.3 Relative shaft vibration
The criterion adopted for the relative shaft vibration measurement shall be the vibratory peak-
to-peak displacement (S ) in the direction of measurement from ISO 20816-1.
p-p
5 Measurement equipment
The measurement equipment shall be capable of measuring broadband RMS vibration with flat
response over a frequency range of 10 Hz to 1 000 Hz, in accordance with the requirements of
–1
ISO 2954. However, for machines with speeds approaching or below 600 min , the lower limit
of the flat response frequency range shall not be greater than 2 Hz.
Measurement equipment for relative shaft vibration measurements shall comply with the
requirements in ISO 10817-1.
Multi-directional vibration sensors shall not be used.
NOTE Multi-directional sensors do not provide proper vibration measurement in all directions when mounted in only
one location.
6 Machine mounting
6.1 General
The vibration of an electrical machine is closely linked with the mounting of the machine. To
permit evaluation as far as balance and vibration of rotating electrical machines are
concerned, it is necessary to measure the vibration on the machine alone, under properly
determined test conditions, to enable reproducible tests to be carried out and to provide
comparable measurements.
6.2 Free suspension
This condition is achieved by suspending the machine on a spring or by mounting on an elastic
support (springs, rubber, etc.).
The h i g h e s t natural oscillation frequency (f ) of the suspension system and machine shall
no
be less than 1/3 of the frequency f corresponding to the speed of the machine under test, as
defined in 7.3. Based on the mass of the machine being tested, the necessary elasticity of the
–1 –1
suspension system as a function of rated speed from 600 min to 3 600 min can be
–1
determined from Figure 1. For speeds lower than 600 min measurements in free suspension
–1
are not practical. For speeds greater than 3 600 min , the static displacement Z should be not
–1
less than the value for 3 600 min .
The curve in Figure 1 presents the minimum elastic displacement to attain the necessary
vertical rigid body natural oscillation, which is usually the highest rigid body natural frequency.
Static displacement Z is expressed as:
ag f
Z =           ,a = ; a 3
f
2πn no
( )
where
Z is the displacement in m,
–1
n is the rated speed in units of s , and
g is the acceleration of gravity (9,81 m/s ).
When a is set to 3, then the curve in Figure 1 is generated.
The suspension system should exhibit linear stiffness characteristics within the operating
displacement range.
6.3 Rigid mounting
6.3.1 Foundation
6.3.1.1 General
During the shop running factory acceptance test of the assembled machine, vibration
measurements shall be made with the machine properly mounted, shimmed if necessary, and
securely fastened to a massive foundation or test floor stand. Elastic mounts are not permitted.
NOTE 1 For proper mounting, shimming can be applied: Typically shimmed to within 25 µm to 50 µm (approximately
1 mil to 2 mil) to avoid soft foot.
The horizontal and vertical natural frequencies of the complete test arrangement shall not
coincide within:
a) ±10 % of the rotational frequency of the machine;
b) ±5 % of twice the rotational frequency; or
c) ±5 % of once and twice the fundamental electrical line supply frequency.
NOTE 2 These criteria apply to each rated speed according to 7.3.1.
Either one of the following two mounting conditions may be chosen by the manufacturer.
6.3.1.2 Rigid mounting on massive foundation
One indication of massive foundation is when the vibration velocity measured in the horizontal
and vertical directions at the machine feet (or at the base frame near to the bearing pedestals
or stator feet) does not exceed 30 % of the maximum velocity, which is measured at the adjacent
bearing housing in the same measurement direction. The ratio of foot to bearing vibration
velocities is valid for the rotational frequency component or twice-line frequency component (if
the latter is being evaluated).
NOTE 1 The rigidity of a foundation is a relative quantity. It is compared with the rigidity of the machine bearing
system. The ratio of bearing housing vibration to foundation vibration is a characteristic quantity for the evalu ation
of foundation flexibility.
NOTE 2 If the machine is to be supported in the field by a structure other than a massive foundation, it may be
necessary to perform a system dynamic analysis to make the necessary changes to the foundation dynamic stiffness.
If the machine will be installed in the field (in situ) on a structure that is not a massive foundation, a system dynamic
analysis can be required to assess and adjust the dynamic stiffness of the field supporting structure.
6.3.1.3 Rigid mounting on test floor stand
This condition is achieved by mounting the machine on an adequately rigid test foundation free
of resonances at forcing frequencies, see 6.3.1.1.
NOTE This mounting is the most used in manufacturers test labs.
6.3.2 Horizontal machines
The machine under test shall be bolted or clamped using all bolt-hole positions to a foundation
that meets the requirements of 6.3.1.2 or 6.3.1.3.
There are constructions and mountings in which the above fixing conditions cannot be met.
Examples include single-bearing or flange mounted machines. In those cases, there should be
an agreement between the supplier and customer.
6.3.3 Vertical machines
Vertical machines shall be mounted onto a solid rectangular or circular steel plate with a bore
hole in the centre of the shaft extension, a machined surface for the flange of electrical machine
being measured and holes provided for fasteners or clamps. The steel plate thickness shall be
at least three times greater than the machine flange thickness, five times is recommended. The
edge length respective to the diameter shall be at least equal to the height of the top bearing,
L. Figure 6 is an example for IM V1 (see IEC 60034-7).
6.3.3.1 Type test
Vertical electrical machines shall be mounted on a solid steel plate, either rectangular or
circular, with the following features:
– a central bore hole aligned with the shaft extension;
– a machined surface to support the machine flange accurately;
– holes for fasteners or clamps to secure the machine.
The steel plate thickness shall be at least three times the flange thickness of the machine; five
times is recommended for improved rigidity. The edge length (or diameter) of the plate shall be
at least equal to the height of the machine's top bearing, denoted as L (see Figure 6).
The steel base shall be clamped firmly and tilt safe to a solid floor and meet the requirements
of 6.3.1.2 or 6.3.1.3. The flange connection shall use the correct number of fasteners or clamps.
When the first natural frequency of the lateral vibration mode of a vertical machine mounted on
a solid foundation is close to the machine's rotational speed, the machine shall be tested on a
different support or foundation to avoid a resonant test condition, as the machine's field support
structure is different from a solid massive foundation.
If the above method of mounting is not reasonable feasible, other arrangements can be
according to agreement between supplier and customer.
6.3.3.2 Routine test
If measurement results according to 6.3.3.1 exist for a particular motor design with bearing
arrangement also suitable for horizontal operation, other motors with a corresponding design
can be tested also in a horizontal position.
The machine shall be mounted on a test support. The test support shall have sufficient stiffness.
The motor shall be clamped or fastened to the test support with the specified number of screws
via the motor flange or feet if any.
Other arrangements can be agreed between supplier and customer.
6.4 Active environment determination
The support systems described in 6.2 and 6.3 are considered passive, admitting insignificant
external disturbances to the machine. When, for the same measurement position, the vibration
magnitude with the machine at standstill exceeds 25 % of the value when the machine is
running, then an active environment is said to exist, and this document does not apply (see
ISO 20816-1).
7 Conditions of measurement
7.1 Key
For the balancing and vibration measurement of machines provided with a shaft extension
keyway, the keyway key shall be considered according to ISO 21940-32, unless specified by
customer.
7.2 Measurement positions and directions
7.2.1 Measurement positions for vibration
The location of the preferred measurement positions and directions to which the levels of
vibration magnitude apply are shown in Figure 2 for machines with end-shield bearings and in
Figure 4 for machines with pedestal bearings. Figure 3 applies to those machines where
measurement positions according to Figure 2 are not possible without disassembly of parts.
When measurements cannot be performed according to Figure 2 or Figure 3, there should be
an agreement between supplier and customer.
Figure 6 applies to machines mounted in the vertical position.
NOTE 1 Measurement according to Figure 3 and Figure 6 might can be on the frame as close to the bearing housing
as possible.
NOTE 2 Axial vibration measurement may It will probably not be possible to measure axial vibration without
disassembly on both ends. If a machine has thrust bearings, this may can be according to agreement between
supplier and customer, see 8.3.
7.2.2 Measurement positions for relative shaft displacement
Non-contacting transducers shall be installed inside the bearing, measuring directly the relative
shaft journal displacement, or (when inside mounting is not possible) adjacent to the bearing
shell. The preferred radial positions are as indicated in Figure 5.
7.3 Test conditions
7.3.1 Direct-on-line
Machines shall be tested at no-load with all relevant quantities at their rated value each rated
frequency (50 Hz / 60 Hz) and the corresponding rated voltage.
Fixed speed AC machines shall be run with a sinusoidal supply voltage according to IEC 60034-
1.
The test shall be performed at each rated fixed speed or over the rated speed range for variable
frequency drives. For all tested speeds, the values shall not exceed the corresponding limit in
Table 1.
In order to discern the mechanically induced vibration from other vibration excitation forces, it
is recommended that DC machines are tested with a low current ripple supply or pure DC.
NOTE Tests with variable-frequency power supply normally only confirm mechanically induced vibrations. It is
possible that electrically induced vibrations will be different. If possible, the tests with the actual converter to be
installed with the motor on site will provide better information about vibration behaviour.
NOTE When rated voltage cannot be achieved, the motor can be tested at lower voltage with a winding/connection
that achieves rated flux or according to agreement with the customer.
For multi-speed motors (e.g. pole changing windings) the test shall be performed for each pole
number. For all tested speeds, the values shall not exceed the corresponding limit in Table 1.
For machines that are bi-directional, the vibration limits apply for both directions of rotation but
should be measured in only one direction.
7.3.2 Variable speed
The type test shall be performed over the specified speed range (or ranges) with a speed ramp
(up or down) or coast down slow enough to detect the peak levels. The measured vibration
values shall not exceed the corresponding limit in Table 1.
NOTE 1 De-energized coast down test can be done to evaluate mechanical vibration source peaks throughout the
speed operation range.
NOTE 2 Tests with variable-frequency power supply will only confirm mechanically induced vibrations. It is possible
that electrically induced vibrations might also be present. Testing with the actual converter installed with the motor
in situ will provide better information about vibration behaviour.
For routine testing of variable speed machines, it is permitted to test at a single speed based
upon information obtained during type test.
For machines that are bi-directional, the vibration limits apply for both directions of rotation, but
need to be measured in only one direction.
To discern the mechanically induced vibration from other vibration excitation forces, it is
recommended to use the coast down test. DC machines are to be tested with a low current
ripple supply or pure DC.
7.4 Vibration transducer
The mounting of the transducer used for vibration measurement on the machine surface shall
be as specified by the manufacturer of the transducer and shall not disturb the vibratory
condition of the machine under test.
For this, it is necessary that the total coupled mass of the transducer assembly isbe less than
1/50 of the mass of the machine.
8 Limits of bearing housing vibration
8.1 Limits of vibration magnitude
The limits apply to the measured broadband RMS vibration velocity and displacement in the
frequency range specified in Clause 5.
The vibration magnitude for DC and three phase AC machines with shaft heights 56 mm and
higher, for one of either of the two mounting conditions according to Clause 6, shall not exceed
the limits specified in Table 1. Limits are given for two vibration grades. When no grade is
specified, machines complying with this document shall be grade A.
–1
For routine tests of standard machines with rotational speeds less than 600 min , vibration is
–1
to be expressed in units of displacement. For rotational speeds from 600 min up to
–1
15 000 min , vibration is to be expressed in units of velocity.
When the routine test is made with a free suspension mounting condition, the type test should
also include testing with rigid mounting. This is valid for the whole speed range of this standard.
Table 1 – Limits of maximum vibration magnitude in
displacement (RMS) and velocity (RMS) for shaft height H
Vibration Shaft height, 56 ≤ H ≤ 132 H > 132
grade
mm
Mounting Displacement Velocity Displacement Velocity
µm mm/s µm mm/s
A Free suspension 4525 2,81,6 45 2,8
Rigid mounting – – 37 2,3
a
2,8
B Free suspension 18 1,1 29 1,8
Rigid mounting – – 24 1,5
a
1,8
Grade A applies to machines with no special vibration requirements.
Grade B applies to machines with special vibration requirements.
Rigid mounting is not considered acceptable for machines with shaft heights less than or equal to 132 mm.
Vibration at frequencies above 1 000 Hz should be filtered out.
The shaft height of a machine without feet, or a machine with raised feet, or any vertical machine is to be taken
as the shaft height of a machine in the same basic frame, but of the horizontal shaft foot-mounting type.
a
This level is the limit when the twice-line frequency vibration level is dominant as defined in 8.2 and explained
in Figure 7.
NOTE 1 The manufacturer and the purchaser will consider that the instrumentation can have a measurement
tolerance of 10 %.
NOTE 2 A machine which is well-balanced in itself and of a grade conforming with Table 1 may can exhibit large
vibrations when installed on site, arising from various causes, such as unsuitable foundations, reaction of the driven
machine, current ripple from the power supply, etc. Vibration may can also be caused by driving elements with a
natural oscillation frequency very close to the excitation due to the small residual unbalance of the rotating masses
of the machine. In such cases, checks can be carried out on site not only on the machine, but also on each element
of the installation. (See ISO 10816-3 ISO 20816-3.)
NOTE 3 As mentioned for onsite operation in ISO 20816-1, special agreements can be made. The values given in
ISO 20816-1 are the basis for the ease of discussion and agreement between the supplier and the user. The values
ensure in most applications that major errors or unrealistic requirements are avoided. Special agreements are also
made for acceleration and deceleration ramps. Short term vibration limits and reduced bearing lifetime as a function
of vibration velocity can be given by the manufacturer.
8.2 Limits of vibration velocity with twice-line frequency for AC machines
Two-pole induction machines may can have electromagnetic excited vibration at twice the
frequency of the power system. The correct evaluation of these vibration components requires
a rigid mounting of the machine, which complies with the requirements given in 6.3.
When type tests demonstrate a dominant twice-line frequency component for machines having
H > 132 mm, the vibration magnitude limit in Table 1 (for Grade A) is increased to 2,8 mm/s from
2,3 mm/s or (for Grade B) is increased to 1,8 mm/s from 1,5 mm/s. Greater values are subject
to prior agreement. A twice-line frequency component is considered dominant when type tests
demonstrate it to be greater than 70 % of 2,3 mm/s (for Grade A) or 70 % of 1,5 mm/s (for
Grade B). Graphical interpretation of the definition above is shown in Figure 7.
NOTE 1 With respect to the twice-line frequency component agreements between the supplier and the customer
can be made.
NOTE 2 70 % approximates to 100 % , where the RMS values of rotational and twice-line frequency are equal.
8.3 Axial vibration
The evaluation of axial bearing vibration depends on the bearing function and bearing
construction.
In the case of thrust bearings, axial vibration correlates with thrust pulsations, which could
cause damage to the metal liner of sleeve bearings or to parts of antifriction bearings. Axial
vibration of these bearings shall be evaluated in the same manner as tran sverse vibration and
Table 1 limits apply.
For bearings having no axial limiting construction such as sleeve bearings with no axial thrust
bearing, the requirement may be relaxed by prior agreement.
9 Limits of relative shaft vibration
Relative shaft vibration measurements are recommended only for sleeve bearing machines with
–1
speeds > 1 200 min ; rated power > 1 000 kW; and shall be subject to prior agreement with
respect to the necessary provisions regarding the installation of shaft measurement
transducers.
When machines with sleeve bearings have special provisions for the installation of shaft
vibration measurement transducers, the limits for the relative shaft vibration displacement are
specified in Table 2. These limits are in addition to those required in Clause 8.
Table 2 – Limits for the maximum shaft vibration (S ) and the maximum run-out
p-p
Maximum combined mechanical
Vibration grade Speed range Maximum relative shaft displacement
and electrical run-out
–1
µm µm
min
A > 1 800 65 16
≤ 1 800 90 23
B > 1 800 50 12,5
≤ 1 800 65 16
Grade B applies to machines with special vibration requirements.
The maximum relative shaft displacement limits include the run-out. For the definition of the run-out see ISO 20816-
1 ISO 2041:2018, 3.4.29.
Electrical run-out can be so large that it can mask true shaft vibration. As a result, it can be
necessary to:
– make slow-roll compensations,
– install a sleeve to reduce inhomogeneities in the original shaft surface,
– fix the rotor for reduction of axial movements during the measurement.
NOTE Proximeter sensors (eddy current sensors) are mostly used, because they are maintenance free and robust,
but due to nonavoidable inhomogeneity at the measuring and at the extended surface due to the axial movement at
no load, eddy current sensors are very error sensitive. For the run-out with rotor in machine housing or lathe or in
extra V-block bearing arrangement test and mechanical sensors can be used for error clarification.
Key
A machine under test
Z displacement
Figure 1 – Minimum elastic displacement as a function of rated speed
To reduce the influence of the mass and the moments of inertia of the suspension system on
the vibration level, the effective mass of the elastic support shall be not greater than 1/10 % of
that of the machine.
Figure 2 – Preferred positions of measurement applicable to
one or both ends of the machine

Figure 3 – Measurement positions for those ends of machines where measurements
according to Figure 2 are not possible without disassembly of parts
Figure 4 – Measurement positions for pedestal bearing

Key
A signal conditioner
B transducer
Figure 5 – Preferred circumferential position of transducers
for the measurement of relative shaft displacement
Figure 6 – Measurement positions for vertical machines (measurements to be made
at the bearing housing; when not accessible, then as close as possible)

Figure 7 – Vibration limit diagram for shaft heights H > 132 mm
BIbliography
IEC 60034-7, Rotating electrical machines - Part 7: Classification of types of constructions and
mounting arrangements (IM Code)
ISO 2041:2018, Vibration and shock vocabulary Mechanical vibration, shock and condition
monitoring - Vocabulary
ISO 7919-3, Mechanical vibration of non-reciprocating machines – Measurements on rotating
shafts and evaluation criteria – Part 3: Coupled industrial machines
ISO 10816-3, Mechanical vibration – evaluation of machine vibration by measurements on non-
rotating parts – Part 3: Industrial machines with rated power above 15 kW and rated speeds
between 120 r/min and 15 000 r/min when measured in situ
ISO 20816 (all parts), Mechanical vibration - Measurement and evaluation of machine vibration
ISO 20816-3, Mechanical vibration - Measurement and evaluation of machine vibration - Part 3:
Industrial machinery with a power rating above 15 kW and operating speeds between 120 r/min
and 30 000 r/min
API Standard 541:2014, Form-wound squirrel cage induction motors - 250 horsepower and
larger
API Standard 546:20082022, Brushless synchronous machines - 500 horsepower and larger
API Standard 547:2017, General Purpose Form-wound Squirrel Cage Induction Motors -
185 kW (250 hp) and through 2 240 kW (3 000 hp)
IEEE Standard for Petroleum and Chemical Industry 841:2009, Premium-Efficiency,
Severe-Duty, Totally Enclosed, Fan-Cooled (TEFC) Squirrel Cage Induction Motors-Up to and
Including 370 kW (500 hp)
NEMA MG 1:2016 00001:2024, Motors and Generators - Part 7: Mechanical vibration
measurement, evaluation and limits
___________
IEC 60034-14 ®
Edition 5.0 2026-11
INTERNATIONAL
STANDARD
Rotating electrical machines -
Part 14: Mechanical vibration of certain machines with shaft heights 56 mm and
higher - Measurement, evaluation and limits of vibration severity
ICS 29.160.01 ISBN 978-2-8327-1585-7

CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Measurement quantities . 6
4.1 General . 6
4.2 Vibration magnitude . 6
4.3 Relative shaft vibration . 6
5 Measurement equipment . 6
6 Machine mounting . 7
6.1 General . 7
6.2 Free suspension .
...