ISO 13373-10:2024
(Main)Condition monitoring and diagnostics of machines — Vibration condition monitoring — Part 10: Diagnostic techniques for electrical generators with fluid-film bearings
Condition monitoring and diagnostics of machines — Vibration condition monitoring — Part 10: Diagnostic techniques for electrical generators with fluid-film bearings
This document gives guidelines and requirements for the procedures to be followed when carrying out vibration diagnostics of 2‑ and 4‑pole electrical generators of cylindrical pole design with fluid-film bearings. This document does not apply to salient pole generators. This document establishes a practical step-by-step vibration-based approach to fault diagnosis. The requirements of this document should be considered together with those in ISO 13373-4.
Surveillance et diagnostic d'état des machines — Surveillance des vibrations — Partie 10: Techniques de diagnostic pour les générateurs électriques de puissance à paliers à film fluide
General Information
Standards Content (Sample)
International
Standard
ISO 13373-10
First edition
Condition monitoring and
2024-06
diagnostics of machines —
Vibration condition monitoring —
Part 10:
Diagnostic techniques for electrical
generators with fluid-film bearings
Surveillance et diagnostic d'état des machines — Surveillance des
vibrations —
Partie 10: Techniques de diagnostic pour les générateurs
électriques de puissance à paliers à film fluide
Reference number
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Measurements . 2
4.1 Vibration measurements .2
4.2 Machine operational parameter measurement .2
5 Initial analysis . 2
6 Specific analysis of electrical generators with fluid-film bearings . 2
7 Considerations when recommending actions . 3
Annex A (normative) Systematic approach to the vibration analysis of electrical generators
with fluid-film bearings — Fault tables . 4
Annex B (informative) Methodology for diagnosing vibration problems in electrical generators
with fluid-film bearings . 8
Annex C (informative) Examples of faults occurring in electrical generators with fluid-film
bearings .12
Bibliography .20
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO 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, ISO 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
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 108, Mechanical vibration, shock and condition
monitoring, Subcommittee SC 2, Measurement and evaluation of mechanical vibration and shock as applied to
machines, vehicles and structures.
A list of all parts in the ISO 13373 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
This document provides guidelines for the procedures to be considered when carrying out vibration
diagnostics of electrical generators with fluid-film bearings. It is intended to be used by vibration
practitioners, engineers and technicians and it provides them with useful diagnostic tools which include the
use of flowcharts and fault tables.
ISO 20816-2 sets out the criteria for monitoring the vibration of gas turbines, steam turbines and generators
in excess of 40 MW and establishes provisions for evaluating the severity of the in-situ, broad-band vibration.
ISO 13373-1 presents the basic procedures for analysing narrow-band vibration signals. It includes the
types of transducers to be used, their ranges, their recommended mounting locations on various types of
machines, on-line and periodic vibration monitoring systems and potential machinery problems.
ISO 13373-2 includes descriptions of the signal conditioning equipment that is required, the time and
frequency domain techniques that can be used and the waveforms and signatures that represent the most
common machinery operating phenomena or faults encountered when performing vibration signature
analysis.
ISO 13373-3 describes some procedures to determine the causes of vibration problems common to all types
of rotating machines. It includes descriptions of systematic approaches that can be used to characterize
vibration effects, the diagnostic tools available, which tools are needed for particular applications and
recommendations on how the tools can be used for different machine types and components. ISO 13373-3
does not preclude the use of other diagnostic techniques.
Note that ISO 17359 indicates that diagnostics can be
a) started after detection of an anomaly during machine monitoring, or
b) carried out in parallel with machine monitoring.
This document considers only where diagnostics are performed after an anomaly has been detected and
focusses mainly on the use of flowcharts, process tables, fault and symptom tables as diagnostic tools, since
it is felt that these are the tools that are most appropriate for use in the field.
The flowchart and diagnostic process table methodology presents a structured procedure for use by a
person in the field to diagnose a fault and find its cause. This step-by-step procedure guides the practitioner
to be able to diagnose the machine anomaly in order to establish the probable root cause of this anomaly.
The fault tables present a list of the most common faults found in machinery, as well as their manifestations
in the machine and vibration data. The symptom tables contain the main distinguishing vibration features of
the main faults. When used with the flowcharts, the tables assist with the identification of machinery faults.
When approaching a machinery problem that manifests itself as a high or erratic vibration signal, the
diagnosis of the problem should be done in a systematic manner. This document and ISO 13373-3 achieve
that by providing guidance regarding the selection of the measuring and analysis tools, their use and the
step-by-step procedures that can be used to diagnose the problem.
v
International Standard ISO 13373-10:2024(en)
Condition monitoring and diagnostics of machines —
Vibration condition monitoring —
Part 10:
Diagnostic techniques for electrical generators with fluid-film
bearings
1 Scope
This document gives guidelines and requirements for the procedures to be followed when carrying out
vibration diagnostics of 2- and 4-pole electrical generators of cylindrical pole design with fluid-film bearings.
This document does not apply to salient pole generators.
This document establishes a practical step-by-step vibration-based approach to fault diagnosis.
The requirements of this document should be considered together with those in ISO 13373-4.
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.
ISO 2041, Mechanical vibration, shock and condition monitoring — Vocabulary
ISO 13372, Condition monitoring and diagnostics of machines — Vocabulary
ISO 13373-1, Condition monitoring and diagnostics of machines — Vibration condition monitoring — Part 1:
General procedures
ISO 13373-2, Condition monitoring and diagnostics of machines — Vibration condition monitoring — Part 2:
Processing, analysis and presentation of vibration data
ISO 13373-3:2015, Condition monitoring and diagnostics of machines — Vibration condition monitoring —
Part 3: Guidelines for vibration diagnosis
ISO 21940-2, Mechanical vibration — Rotor balancing — Part 2: Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 2041, ISO 13372 and ISO 21940-2 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Measurements
4.1 Vibration measurements
Vibration measurements may be obtained using two main categories of transducers:
a) non-contacting (e.g. inductive, capacitive and eddy current probes used on rotating shafts);
b) seismic (e.g. accelerometers or velocity transducers used on non-rotating parts, such as the bearing
housing).
International Standards have been written to help in assessing the vibration severity for both types of
measurements (e.g. ISO 20816 (all parts) and ISO 10816 (all parts)).
It is important to recognize that the appropriate transducer, signal conditioning, measurement and analysis
system shall be used for the diagnosis of faults related to electrical generators with fluid-film bearings.
Before any measurements are taken, it is good practice to consider whether the grounding (earthing) and
electrical fields of the machine will have any effect on them.
Descriptions of the transducers, measurement systems and analysis techniques are given in ISO 13373-1
and ISO 13373-2, which shall be used as appropriate.
Other diagnostic technologies are available for taking measurements on generators that can be considered
in specific cases (e.g. model based voltage and current systems, strain gauges and optical sensors).
Many electrical generators are equipped with stator end-winding and core vibration monitoring systems. For
guidelines regarding generators with end-winding vibration measurement systems see IEC/TS 60034-32.
Evaluation of the measurement results is very design specific and outside of the scope of this document.
It is recommended to adhere to the manufacturer’s and service provider’s guidelines regarding end-winding
and core vibration evaluation for specific machine designs and/or similarly designed units.
4.2 Machine operational parameter measurement
Data from operational parameters (e.g. rotational speed, load, mounting configuration [with solid or
flexible support arrangement] and temperature) that can have an influence on the machine vibration and
characteristics are important to acquire in order to arrive at an appropriate fault diagnosis. For a given
machine, operational parameters can be associated with a range of steady state and transient operating
conditions.
5 Initial analysis
The analysis shall be performed using the guidelines given in ISO 13373-3:2015, Annex A.
This analysis shall identify and include any safety concerns, such as the presence of high vibration and
its vibration severity, past vibration history, effect of operating parameters on machine vibration, the
consequences of not taking corrective action and the need for machine shutdown.
The analysis shall also include items such as the machine mounting configuration, machine position relative
to other rotating machines, building structure in which the machine is installed and the environment in
which the machine operates (see ISO 13373-3:2015, Annex B to Annex D for a description of common faults
resulting from machine installation and bearing defects).
6 Specific analysis of electrical generators with fluid-film bearings
The specific analysis shall be performed using Annex A, which presents the most prevalent generator defects
that cause excessive vibration. Annex A also includes the identification of generator vibration resulting from
hydrodynamic bearing problems. However, the root cause of and remedial actions that can be taken to
resolve such problems are addressed separately in ISO 13373-3:2015, Annex C.
The fault table to be used for the diagnosis of electrical generators is given by Table A.1, the symptom table
is given in Table A.2, while the methodology of vibration diagnosis is presented in Annex B. Examples of the
use of the fault table, symptom table and methodology of vibration diagnosis of electrical generators are
given in Annex C.
Due to their method of rotor construction, 2-pole and, to a lesser extent, 4-pole electrical generators produce
a 2× excitation force and a corresponding 2× vibration. This is an inherent characteristic of generator rotor
design and some level of 2× vibration is normal and expected. Also, 2× line frequency (100 Hz or 120 Hz)
excitation from the rotating electromagnetic field in the stator is present during operation and can excite
structural resonances (e.g. in the machine pedestal and/or frame).
For a 2-pole generator synchronized to the grid, 2× line frequency corresponds to 2× frequency of rotation
and is therefore hard to separate for diagnostic purposes.
One of the most common causes of high vibration in a generator is a transient rotor bend due to shorted
turns. The shorted turns develop over time due to normal insulation degradation and can be diagnosed by
specialized testing, which is described, for example in Reference [1], pp. 875 to 902. The same reference also
provides details for performing thermal sensitivity testing and analysis (Reference [1], pp. 907 to 912) and
heat-run testing (Reference [1], pp. 913 to 914) which is also useful for detecting issues with cooling gas flow.
7 Considerations when recommending actions
Several factors influence any remedial or corrective actions that can be taken, such as:
a) their safety;
b) commercial considerations;
c) incorrect machine design;
d) machine assembly issues.
Clearly, the appropriate action(s) for a particular diagnosis depend(s) on individual circumstances and it
is beyond the scope of this document to make specific recommendations. Nevertheless, it is important to
consider possible actions resulting from the diagnosis and the implications of those actions.
Recommended actions depend on the degree of confidence in the fault diagnosis (e.g. if the same diagnosis
has been made correctly before for this machine), the fault type and severity as well as on safety and
commercial considerations. It is neither possible nor the aim of this document to recommend action(s) to be
taken to cover all circumstances.
Annex A
(normative)
Systematic approach to the vibration analysis of electrical generators
with fluid-film bearings — Fault tables
A systematic approach to the vibration analysis of electrical generators is shown b
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...