ISO 23048:2018

Ships and marine technology - Verification method for portable power measurement using a strain gauge

This document specifies a procedure for the verification of portable power measurement equipment using a strain gauge in the laboratory. The power measurement equipment verified in accordance with this document can be used on merchant ships.

Titre manque

General Information

• Status: Published
• Publication Date: 03-Jul-2018
• ICS: 47.020.01 - General standards related to shipbuilding and marine structures
• Technical Committee: ISO/TC 8/SC 2 - Marine environment protection
• Drafting Committee: ISO/TC 8/SC 2 - Marine environment protection
• Current Stage: 9093 - International Standard confirmed
• Start Date: 13-Dec-2023
• Completion Date: 13-Dec-2025

Overview

ISO 23048:2018 - Ships and marine technology - Verification method for portable power measurement using a strain gauge - specifies a laboratory procedure to verify portable shaft power measurement equipment that uses strain gauges. The verified portable equipment can be used on merchant ships for shaft power and engine performance assessment. The standard describes the verification system composition (torque generator, RPM generator, torque sensor), installation guidelines, test procedure, and reporting requirements.

Key Topics and Technical Requirements

• Verification equipment composition: torque arm, weight surface plate, torque arm axis, shaft, torque sensor (or verified permanent torque sensor/strain gauges) and an RPM generator.
• Torque generation: Real torque is produced by calibrated weights on a torque arm of known length; shaft material properties must be stated in the test report (see ISO 15016 reference).
• RPM generation and control: an RPM generator (0–1 000 RPM capability implied) and a tacho sensor are used to supply and measure precise RPM. RPM error rates must be recorded and measured at least five times per test condition. Calibration by an ISO/IEC 17025 facility is recommended.
• Strain gauge measurement principle: strain gauges detect shaft distortion via resistance change (usually measured with a Wheatstone bridge). Shaft distortion combined with RPM yields shaft power (kW).
• Installation and performance requirements (Annex A): strain gauge attachment on the intermediate shaft (not on flange or bearing), surface preparation (cleaning, degreasing), temperature control during bonding, angular alignment within ±1.5°, and integrity checks (E output ≤ ±0.5 mV/V with engine stopped).
• Test procedure and reporting: install the portable shaft power meter, verify strain gauge attachment, apply calibrated weights to generate torque, compare outputs between the verification equipment and the portable meter, record torque and RPM error rates, and prepare the verification test report per Annex C.

Practical Applications and Users

• Use cases:
  • Pre-sea trial verification of portable shaft power meters.
  • Calibration checks for on-board portable instrumentation used during speed and power trials.
  • Quality control for manufacturers of portable strain-gauge-based shaft power meters.
• Typical users:
  • Marine surveyors, shipbuilders, and ship operators conducting speed/power trials.
  • Testing and calibration laboratories (including ISO/IEC 17025 labs).
  • Naval architects, marine engineers, and equipment manufacturers.
  • Classification societies and purchasers specifying verification before use on merchant ships.

Related Standards

• ISO 15016:2015 - Guidelines for assessment of speed and power performance by analysis of speed trial data (referenced in ISO 23048:2018).
• ISO/IEC 17025 - Laboratory competence for calibration of RPM and other verification instruments (recommended for RPM generator calibration).

Keywords: ISO 23048:2018, strain gauge, portable power measurement, shaft power meter verification, torque generator, RPM generator, ships and marine technology.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 23048
First edition
2018-07
Ships and marine technology —
Verification method for portable power
measurement using a strain gauge
Titre manque
Reference number
©
ISO 2018
© ISO 2018
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: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Composition of the shaft power meter verification equipment . 2
4.1 General . 2
4.2 Torque generator and RPM generator .2
4.2.1 General. 2
4.2.2 Torque generator.2
4.2.3 RPM generator.2
5 Guidelines for installation and verification test . 3
5.1 General . 3
5.2 Installation guidelines .4
6 Test procedure . 5
7 Test report . 5
8 Verification . 5
Annex A (normative) Installation and verification method — Strain gauge . 6
Annex B (informative) Shaft power measurement — Strain gauge (portable type) . 9
Annex C (normative) Verification test report for shaft power meter (strain gauge) .14
Bibliography .15
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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on 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 the following
URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology,
Subcommittee SC 2, Marine environment protection.
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 © ISO 2018 – All rights reserved

INTERNATIONAL STANDARD ISO 23048:2018(E)
Ships and marine technology — Verification method for
portable power measurement using a strain gauge
1 Scope
This document specifies a procedure for the verification of portable power measurement equipment
using a strain gauge in the laboratory.
The power measurement equipment verified in accordance with this document can be used on
merchant ships.
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 15016:2015, Ships and marine technology — Guidelines for the assessment of speed and power
performance by analysis of speed trial data
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
strain gauge
gauge used to measure the strain on an object
Note 1 to entry: As the object is deformed it causes a change in electrical resistance. This change in resistance,
usually measured using a Wheatstone bridge, is related to the strain by the quantity known as the gauge factor.
3.2
shaft power meter verification equipment
equipment designed to provide a real torque, produced by a torque arm weighted with a known exact
mass, to the torque measurement device
3.3
portable power measurement equipment
equipment temporarily installed on the ship and operated during a sea trial to measure the power
delivered to the propeller by the engine and transmission systems, as opposed to the fixed-type shaft
power measurement equipment, if installed
4 Composition of the shaft power meter verification equipment
4.1 General
The verification equipment is composed of a torque arm, a weight surface plate, a torque arm axis, a
shaft, a torque sensor, a weight and an RPM (revolutions per minute) generator. See Figure 1. The real
torque is generated by weights with known exact mass, attached to a torque arm of known length which
is attached to the shaft.
Shaft torque shall be measured by means of a verified permanent torque sensor or strain gauges on
the shaft.
4.2 Torque generator and RPM generator
4.2.1 General
Torque and RPM are needed for calculating the shaft power output. The ship’s power output can be
simulated by multiplying the RPM, which are generated by an RPM generator, generating exact RPM,
and the torque which is generated by a torque generator.
4.2.2 Torque generator
Torque is applied to the shaft by a torque generator using weights with exact mass and a torque arm
with exact length, see Figure 2. Weight shall be corrected and calibrated accurately.
The shaft material properties of the torque generator shall be stated in a test report in accordance with
ISO 15016:2015, 6.1.
4.2.3 RPM generator
a) The RPM generator is composed of a body of revolution, which can be controlled from 0 RPM to
1 RPM, and a tacho sensor which measures the number of revolutions.
b) The RPM generator shall control the RPM precisely. It shall be designed to attach to the various
types of tacho sensors to be linked with the shaft power device.
c) The RPM generator shall be capable of displaying the current RPM status data. The RPM error rate
shall be recorded in the test report as specified in Annex C.
d) The RPM generator should be calibrated by a facility meeting ISO/IEC 17025. If it is not, it should be
verified by a calibrated tachometer.
e) The engine RPM generator shall be included for exact verification of the shaft power meter as
shown in Figure 1.
f) The RPM error rate shall be measured at least five times for each of the RPM testing conditions.
2 © ISO 2018 – All rights reserved

Key
1 motor precise control system
2 precise servo meter
3 rotating shaft
4 tachometer
5 shaft power verification simulator (SW)
6 control and data processing unit
7 torque arm
8 torque
9 weig
...

ISO 23048
2018-07
ISO TC 8/SC 2/WG8
Secretariat: ANSI
Ships and marine technology —Verification method for portable power measurement
using a strain gauge
© ISO 2018, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH‐1214 Vernier, Geneva, Switzerland
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
[e-mail]
www.iso.org
Deleted: Error! Hyperlink
reference not valid.¶
1 Scope 1¶
Contents
Error! Hyperlink reference
not valid.¶
3 Terms and definitions 1¶
Foreword . 5
Error! Hyperlink reference
not valid.¶
1  Scope . 1
4.1 General 2¶
2  Normative references . 1
Error! Hyperlink reference
not valid.¶
3  Terms and definitions . 1
4.2.1 General 2¶
Error! Hyperlink reference
4  Composition of shaft power meter verification equipment . 2
not valid.¶
4.1  General . 2
4.2.3 RPM generator 2¶
4.2  Torque generator and RPM generator . 2
Error! Hyperlink reference
4.2.1  General . 2  not valid.¶
5 Guidelines for installation
4.2.2  Torque generator . 2
and verification test 3¶
4.2.3  RPM generator . 2
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not valid.¶
Figure 1 — Composition of verification equipment . 3
5.2 Installation
5  Guidelines for installation and verification test . 3  guidelines 4¶
Error! Hyperlink reference
5.1  General . 3
not valid.¶
5.2  Installation guidelines . 4
Figure 2 — Torque
generator 5¶
Table 1 — Installation guidelines . 4
Error! Hyperlink reference
Figure 2 — Torque generator . 5  not valid.¶
7 Test report 5¶
6  Test procedure . 5
Error! Hyperlink reference
not valid.¶
7  Test report . 5
Annex A (Normative)
Installation and verification
8  Verification . 5
method – Strain gauge 6¶
Error! Hyperlink reference
Annex A (Normative) Installation and verification method – Strain gauge . 6
not valid.¶
A.1  Principle of the measurement test . 6
A.1.1 Measurement of shaft
distortion 6¶
A.1.1  Measurement of shaft distortion . 6
Error! Hyperlink reference
not valid.¶
A.1.2  Measurement of shaft speed . 6
A.1.3 Measurement of shaft
power 6¶
A.1.3  Measurement of shaft power . 6
Error! Hyperlink reference
A.2  Performance requirements for installation of strain gauge shaft power meter . 6
not valid.¶
A.3 Strain gauge installation
A.3  Strain gauge installation method . 6
method 6¶
Error! Hyperlink reference
Figure A.1 — Strain gauge installation . 7
not valid.¶
Figure A.2 — Strain gauge
Figure A.2 — Strain gauge installation (2) . 7
installation (2) 7¶
Error! Hyperlink reference
Figure A.3 — Strain gauge installation (3) . 8
not valid.¶
Annex B (Informative) Shaft power measurement – Strain gauge (portable type) . 9
Annex B (Informative) Shaft
power measurement – Strain
B.1  Device composition . 9
gauge (portable type) 9¶
Error! Hyperlink reference
B.1.1  Strain gauge . 9
not valid.¶
B.1.1 Strain gauge 9¶
... [1]
iii © ISO 2018 – All rights reserved

B.1.2 Frequency transducer. 9
B.1.3 Tele-metric receiver . 9
B.1.4 Electric measurement device . 9
Figure B.1 — Design composition of shaft power meter . 10
B.2 Installation and verification procedure – Strain gauge (portable type) . 10
Figure B.2 — Specimen shaft for strain gauge attached to the shaft . 10
Figure B.3 — Installation of wireless converter . 11
Figure B.4 — Installation of data acquisition device . 12
Annex C (normative) Verification test report for shaft power meter (strain gauge) . 13
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).
Deleted: www.iso.org/directives
Attention is drawn to the possibility that some of the elements of this document may be the subject
of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
Details of any patent rights identified during the development of the document will be in the
Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).
Deleted: www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does
not constitute an endorsement.
For an explanation on 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 the
following URL: www.iso.org/iso/foreword.html.
Deleted: www.iso.org/iso/forewor
d.html
This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology,
Subcommittee SC 2, Marine environment protection.
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.
Deleted: www.iso.org/members.ht
ml
v © ISO 2018 – All rights reserved

Ships and marine technology —Verification method for portable power measurement
using a strain gauge
1 Scope
This document specifies a procedure for the verification of portable power measurement
equipment using a strain gauge in the laboratory.
The power measurement equipment verified in accordance with this document can be used on
Deleted: A
merchant ships.
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 15016:2015, Ships and marine technology — Guidelines for the assessment of speed and
power performance by analysis of speed trial data
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
Deleted: https://www.iso.org/ob
p
— IEC Electropedia: available at http://www.electropedia.org/
Deleted: http://www.electropedi
a.org/
3.1
strain gauge
gauge used to measure the strain on an object
Note 1 to entry: As the object is deformed it causes a change in electrical resistance. This change in
resistance, usually measured using a Wheatstone bridge, is related to the strain by the quantity known as
the gauge factor.
3.2
shaft power meter verification equipment
equipment designed to provide a real torque, produced by a torque arm weighted with a known
exact mass, to the torque measurement device
3.3
portable power measurement equipment
equipment temporarily installed on the ship and operated during a sea trial to measure the
power delivered to the propeller by the engine and transmission systems, as opposed to the
fixed‐type shaft power measurement equipment, if installed
Deleted:
© ISO 2018 – All rights reserved

Deleted: /FDIS
4 Composition of the shaft power meter verification equipment
4.1 General
The verification equipment is composed of a torque arm, a weight surface plate, a torque arm
axis, a shaft, a torque sensor, a weight and an RPM (revolutions per minute) generator. See
Figure 1. The real torque is generated by weights with known exact mass, attached to a torque
arm of known length which is attached to the shaft.
Shaft torque shall be measured by means of a verified permanent torque sensor or strain gauges
on the shaft.
4.2 Torque generator and RPM generator
4.2.1 General
Torque and RPM are needed for calculating the shaft power output. The ship’s power output can
Deleted: A torque
be simulated by multiplying the RPM, which are generated by an RPM generator, generating
exact RPM, and the torque which is generated by a torque generator.
4.2.2 Torque generator
Torque is applied to the shaft by a torque generator using weights with exact mass and a torque
Deleted: A torque
arm with exact length, see Figure 2. Weight shall be corrected and calibrated accurately.
The shaft material properties of the torque generator shall be stated in a test report in
accordance with ISO 15016:2015, 6.1.
4.2.3 RPM generator
a) The RPM generator is composed of a body of revolution, which can be controlled from
0 RPM to 1 RPM, and a tacho sensor which measures the number of revolutions.
b) The RPM generator shall control the RPM precisely. It shall be designed to attach to the
various types of tacho sensors to be linked with the shaft power device.
c) The RPM generator shall be capable of displaying the current RPM status data. The RPM
error rate shall be recorded in the test report as specified in Annex C.
d) The RPM generator should be calibrated by a facility meeting ISO/IEC 17025. If it is not, it
should be verified by a calibrated tachometer.
e) The engine RPM generator shall be included for exact verification of the shaft power meter
as shown in Figure 1.
f) The RPM error rate shall be measured at least five times for each of the RPM testing
conditions.
© ISO 2018 – All rights reserved

Deleted:
Key Formatted: Font:
1 motor precise control system
Formatted: Font:
2 precise servo meter
3 rotating shaft
4 tachometer
5 shaft power verification simulator (SW)
6 control and data processing unit
7 torque arm
8 torque
9 weight
10 moment
Figure 1 — C
...