SIST ISO 789-1:2020

SLOVENSKI STANDARD
SIST ISO 789-1:2020
01-november-2020
Kmetijski traktorji - Postopki preskušanja - 1. del: Preskušanje moči na priključni
gredi
Agricultural tractors - Test procedures - Part 1: Power tests for power take-off
Ta slovenski standard je istoveten z: ISO 789-1:2018
ICS:
65.060.10 Kmetijski traktorji in prikolice Agricultural tractors and
trailed vehicles
SIST ISO 789-1:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 789-1:2020

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SIST ISO 789-1:2020
INTERNATIONAL ISO
STANDARD 789-1
Third edition
2018-02
Agricultural tractors — Test
procedures —
Part 1:
Power tests for power take-off
Tracteurs agricoles — Méthodes d'essai —
Partie 1: Essais de puissance à la prise de force
Reference number
ISO 789-1:2018(E)
©
ISO 2018

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SIST ISO 789-1:2020
ISO 789-1:2018(E)

COPYRIGHT PROTECTED DOCUMENT
© 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
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Email: copyright@iso.org
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Published in Switzerland
ii © ISO 2018 – All rights reserved

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SIST ISO 789-1:2020
ISO 789-1:2018(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Measurement units and tolerances . 1
5 General requirements . 2
5.1 Selection. 2
5.2 Running-in and preliminary adjustments . 2
5.3 Manufacturer's instructions . 2
5.4 Repairs . 2
5.5 Preliminary information . 2
5.6 Fuels and lubricants . 3
5.6.1 Selection . 3
5.6.2 Measuring consumption . . . 3
5.6.3 Tractors equipped with diesel particulate filters . 3
5.7 Auxiliary equipment . 3
5.8 Ambient conditions . 3
5.9 Test equipment . 3
5.10 Alternative PTO ratio . 4
5.11 Testing rules . 4
5.12 Required measurements . 4
5.13 Warm-up. 4
6 Test procedure . 4
6.1 Varying engine speed at full load . 4
6.2 Maximum power. 5
6.2.1 Rated engine speed . 5
6.2.2 Standard PTO speed . 5
6.2.3 Absolute maximum power . 5
6.3 Variable loads . 5
6.3.1 Rated engine speed . 5
6.3.2 Standard PTO speed . 5
6.4 Variable loads and varying engine speed . 6
6.4.1 Five additional points for calculating fuel consumption characteristics. 6
6.4.2 Tractors with regenerating particulate filters . 6
6.5 Statement of power rating . 7
7 Test report . 7
Bibliography . 9
© ISO 2018 – All rights reserved iii

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SIST ISO 789-1:2020
ISO 789-1:2018(E)

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 23, Tractors and machinery for agriculture
and forestry, Subcommittee SC 2, Common tests.
This third edition cancels and replaces the second edition (ISO 789-1:1990), which has been technically
revised for the technical harmonization with OECD Code 2: February 2017.
A list of all the parts in the ISO 789 series can be found on the ISO website.
iv © ISO 2018 – All rights reserved

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SIST ISO 789-1:2020
INTERNATIONAL STANDARD ISO 789-1:2018(E)
Agricultural tractors — Test procedures —
Part 1:
Power tests for power take-off
1 Scope
This document specifies test procedures for determining the power available at the power take-off
(PTO) on agricultural tractors of the wheeled, track-laying or semi-track-laying type.
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 500-1, Agricultural tractors — Rear-mounted power take-off types 1, 2, 3 and 4 — Part 1: General
specifications, safety requirements, dimensions for master shield and clearance zone
ISO 500-2, Agricultural tractors — Rear-mounted power take-off types 1, 2 and 3 — Part 2: Narrow-track
tractors, dimensions for master shield and clearance zone
ISO 500-3, Agricultural tractors — Rear-mounted power take-off types 1, 2, 3 and 4 — Part 3: Main PTO
dimensions and spline dimensions, location of PTO
ISO 789-13:2018, Agricultural tractors — Test procedures — Part 13: Vocabulary and specimen test report
ISO 8759-1, Agricultural wheeled tractors — Front-mounted equipment — Part 1: Power take-off and
three-point linkage
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 789-13 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/
4 Measurement units and tolerances
The following units and tolerances apply to the maximum value measured:
— rotational frequency, in revolutions per minute (r/min): ± 0,5 %;
— time, in seconds (s): ± 0,2 s;
— distance, in metres or millimetres (m or mm): ± 0,5 %;
— force, in newtons (N): ± 1 %;
— torque, in newton metres (N·m): ± 1 %;
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SIST ISO 789-1:2020
ISO 789-1:2018(E)

— mass, in kilograms (kg): ± 0,5 %;
— fuel consumption, in kilograms per kilowatt hour (kg/kWh): ± 1 %;
— atmospheric pressure, in kilopascals (kPa): ± 0,2 kPa;
— temperature of fuels, etc., in degrees Celsius: ± 2 °C;
— wet and dry bulb thermometer temperature, in degrees Celsius: ± 0,5 °C.
5 General requirements
5.1 Selection
In the case of a third party performing the assessment, the tractor manufacturer and the third party
shall work together to select a tractor to be submitted for testing. The tractor submitted for the test
shall require a serial number, shall comply with the manufacturer’s product specification, and shall
be operated in accordance with the manufacturer’s instructions. The manufacturer shall provide a
representative to be present throughout the entire testing of the tractor.
5.2 Running-in and preliminary adjustments
5.2.1 The tractor shall be new and run-in prior to the test in accordance with the manufacturer’s
usual instructions. If a third party is responsible for the testing, the third party itself may run-in the
tractor provided an authority of the manufacturer or the manufacturer’s representative, who will remain
responsible for the running-in, is obtained.
The test report shall state the place and duration of running in.
5.2.2 The adjustment of the carburettor or inj
...