IEC 60092-301:2025

IEC 60092-301 ®
Edition 4.0 2025-07
INTERNATIONAL
STANDARD
Electrical installations in ships -
Part 301: Equipment - Generators and motors
ICS 47.020.60 ISBN 978-2-8327-0592-6
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CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Service conditions . 7
4.1 Inclination . 7
4.2 Vibration . 7
4.3 Ambient temperatures . 7
5 General requirements . 7
5.1 General . 7
5.2 Electrical supply. 7
5.3 Entry of water . 7
5.4 Accumulation of moisture and condensation . 8
5.5 Balance . 8
5.6 Shaft currents . 8
5.7 Terminals . 8
5.8 Lubrication . 8
5.9 Running speed . 8
5.10 Testing . 9
5.11 Degree of protection by enclosures . 9
6 Additional requirements for generators . 9
6.1 DC generators . 9
6.1.1 General . 9
6.1.2 AC generators feeding DC systems . 9
6.2 AC generators. 9
6.2.1 General . 9
6.2.2 Steady conditions: tolerances of voltage and waveform . 9
6.2.3 Transient conditions . 9
6.2.4 Steady short-circuit conditions . 10
6.2.5 Emergency generators . 10
6.2.6 AC generators for special purposes . 10
6.3 Parallel operation of ship's service generators . 10
6.3.1 Reactive load sharing . 10
6.3.2 Load sharing. 10
6.3.3 Cyclic irregularity for AC generating sets . 10
6.4 Excitation of AC generators . 11
7 Prime movers . 11
7.1 General . 11
7.2 Governing characteristics . 12
7.3 Lubrication . 12
7.4 Cyclic irregularity . 12
8 Rating plates . 13
9 Documentation . 13
Bibliography . 14

Table 1 – Limits of cyclic irregularity . 13

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Electrical installations in ships -
Part 301: Equipment - Generators and motors

FOREWORD
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IEC 60092-301 has been prepared by IEC technical committee 18: Electrical installations of
ships and of mobile and fixed offshore units. It is an International Standard.
This fourth edition cancels and replaces the third edition published in 1980, Amendment 1:1994
and Amendment 2:1995. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) services conditions were added;
b) IEC 60034-1:2022, has been considered.
The text of this International Standard is based on the following documents:
Draft Report on voting
18/1980/FDIS 18/1987/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 60092 series, published under the general title Electrical installations
in ships, 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.
INTRODUCTION
The IEC 60092 series forms a series of International Standards for electrical installations in
sea-going ships, incorporating good practice and co-ordinating as far as possible existing rules.
These Standards form a code of practical interpretation and amplification of the requirements
of the International Convention on Safety of Life at Sea, a guide for future regulations which
may be prepared and a statement of practice for use by shipowners, shipbuilders and
appropriate organizations.
1 Scope
This part of IEC 60092 is applicable to all rotating electrical machines rated at 750 W or more
for use in ships. It also applies to excitation machines and includes relevant requirements for
prime mover driving generators.
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 60034 (all parts), Rotating electrical machines
IEC 60034-1:2022, Rotating electrical machines - Part 1: Rating and performance
IEC 60092-101:2018, Electrical installations in ships - Part 101: Definitions and general
requirements
IEC 60092-201:2019, Electrical installations in ships - Part 201: System design - General
IEC 60092-501, Electrical installations in ships - Part 501: Special features - Electric propulsion
plant
IEC 60092-503, Electrical installations in ships - Part 503: Special features - AC supply systems
with voltages in the range of above 1 kV up to and including 36 kV
ISO 21940-11, Mechanical vibration - Rotor balancing - Part 11: Procedures and tolerances for
rotors with rigid behaviour
ISO 8528-5:2022, Reciprocating internal combustion engine driven alternating current
generating set
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60092-101 and the
following 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
3.1
prime mover driving generator
prime mover
device that converts energy into useful mechanical energy to drive a generator
3.2
bipolar DC system
system having two poles normally operating at DC voltages of opposite polarity in relation to
earth
[SOURCE: IEC 60050-601:1985, 601-04-03, modified – Replaced "link" with "system".]
4 Service conditions
4.1 Inclination
Electric machines shall be designed for use at all inclinations specified in IEC 60092-101.
Rotating electrical machines above 500 kW shall be placed with their shaft parallel to the
longitudinal axi
...