EN 60974-6:2016

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Matériel de soudage à l'arc - Partie 6: Matériel à service limitéArc welding equipment - Part 6: Limited duty equipment25.160.30Varilna opremaWelding equipmentICS:Ta slovenski standard je istoveten z:EN 60974-6:2016SIST EN 60974-6:2016en01-april-2016SIST EN 60974-6:2016SLOVENSKI
STANDARDSIST EN 60974-6:20111DGRPHãþD

EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 60974-6
January 2016 ICS 25.160.30
Supersedes
EN 60974-6:2011
English Version
Arc welding equipment - Part 6: Limited duty equipment (IEC 60974-6:2015)
Matériel de soudage à l'arc - Partie 6: Matériel à service limité (IEC 60974-6:2015)
Lichtbogenschweißeinrichtungen - Teil 6: Schweißstromquellen mit begrenzter Einschaltdauer (IEC 60974-6:2015) This European Standard was approved by CENELEC on 2015-10-27. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung CEN-CENELEC Management Centre: Avenue Marnix 17,
B-1000 Brussels © 2016 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 60974-6:2016 E SIST EN 60974-6:2016

This document supersedes EN 60974-6:2011. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights. This standard covers the Principle Elements of the Safety Objectives for Electrical Equipment Designed for Use within Certain Voltage Limits (LVD - 2006/95/EC). This document has been prepared under a mandate given to CENELEC by the European Commission and the European Free Trade Association. Endorsement notice The text of the International Standard IEC 60974-6:2015 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following notes have to be added for the standards indicated: IEC 60085 NOTE Harmonized as EN 60085. IEC 60127-1 NOTE Harmonized as EN 60127-1. IEC 60269-1 NOTE Harmonized as EN 60269-1. IEC 60974 NOTE Harmonized in EN 60974 series. IEC 61558-1:2005 NOTE Harmonized as EN 61558-1:2005 (not modified). SIST EN 60974-6:2016

Normative references to international publications with their corresponding European publications The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here: www.cenelec.eu.
Publication Year Title EN/HD Year IEC 60529 -
Degrees of protection provided by enclosures (IP Code) EN 60529 -
IEC 60974-1 2012
Arc welding equipment - Part 1: Welding power sources EN 60974-1 2012
IEC 60974-5 2013
Arc welding equipment - Part 5: Wire feeders EN 60974-5 2013
IEC 60974-7 2013
Arc welding equipment - Part 7:Torches EN 60974-7 2013
IEC 60974-10 -
Arc welding equipment - Part 10: Electromagnetic compatibility (EMC) requirements EN 60974-10 -
IEC 60974-11 -
Arc welding equipment - Part 11: Electrode holders EN 60974-11 -
IEC 61032 1997
Protection of persons and equipment by enclosures - Probes for verification EN 61032 1998
ISO 2503 -
Gas welding equipment - Pressure regulators and pressure regulators with flow-metering devices for gas cylinders used in welding, cutting and allied processes up to 300 bar (30 MPa) EN ISO 2503 -
IEC 60974-6 Edition 3.0 2015-09 INTERNATIONAL STANDARD NORME INTERNATIONALE Arc welding equipment –
Part 6: Limited duty equipment
Matériel de soudage à l’arc –
Partie 6: Matériel à service limité
INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE
ICS 25.160.30
ISBN 978-2-8322-2898-2
– 2 – IEC 60974-6:2015 © IEC 2015 CONTENTS FOREWORD . 6 1 Scope . 8 2 Normative references . 8 3 Terms and definitions . 9 4 Environmental conditions . 10 5 Tests . 10 5.1 Test conditions . 10 5.2 Measuring instruments . 10 5.3 Conformity of components . 10 5.4 Type tests . 10 5.5 Routine tests. 11 6 Protection against electric shock . 11 6.1 Insulation . 11 6.1.1 General . 11 6.1.2 Clearances . 11 6.1.3 Creepage distances . 11 6.1.4 Insulation resistance . 12 6.1.5 Dielectric strength . 12 6.2 Protection against electric shock in normal service (direct contact) . 12 6.2.1 Protection provided by the enclosure . 12 6.2.2 Capacitors . 12 6.2.3 Automatic discharge of supply circuit capacitors . 13 6.3 Protection against electric shock in case of a fault condition (indirect contact) . 13 6.3.1 Protective provisions . 13 6.3.2 Isolation between windings of the supply circuit and the welding circuit . 13 6.3.3 Internal conductors and connections . 13 6.3.4 Additional requirements for plasma cutting systems . 13 6.3.5 Movable coils and cores . 13 6.3.6 Touch current in fault condition . 13 7 Thermal requirements . 15 7.1 Devices for thermal protection and thermal control . 15 7.2 Heating test . 15 7.2.1 Test conditions . 15 7.2.2 Tolerances of the test parameters . 15 7.2.3 Rated maximum welding current . 15 7.2.4 Calculation . 16 7.3 Temperature measurement . 16 7.3.1 Measurement condition . 16 7.3.2 Surface temperature sensor . 16 7.3.3 Resistance . 16 7.3.4 Embedded temperature sensor . 16 7.3.5 Determination of the ambient air temperature . 16 7.3.6 Recording of temperatures . 17 7.4 Limits of temperature . 17 7.4.1 Windings, commutators and slip-rings . 17 SIST EN 60974-6:2016

IEC 60974-6:2015 © IEC 2015 – 3 – 7.4.2 External surfaces . 17 7.4.3 Other components . 17 7.5 Loading test . 17 7.6 Commutators and slip-rings . 18 8 Thermal control device . 18 8.1 Construction . 18 8.2 Location . 18 8.3 Operation . 18 8.4 Resetting . 18 8.5 Operating capacity . 19 8.6 Indication . 19 9 Thermal protection. 19 9.1 Construction . 19 9.2 Location . 19 9.3 Operation . 19 10 Abnormal operation . 20 10.1 General requirements . 20 10.2 Stalled fan test . 20 10.3 Short circuit test . 20 11 Connection to the input supply network . 21 11.1 Input supply . 21 11.1.1 Supply voltage . 21 11.1.2 Supply current . 21 11.1.3 Engine driven welding power source . 21 11.2 Multi supply voltage . 21 11.3 Means of connection to the supply circuit . 21 11.4 Supply circuit terminals . 21 11.5 Cable anchorage . 22 11.6 Inlet openings . 22 11.7 Supply circuit on/off switching device . 22 11.8 Supply cables . 22 11.9 Supply coupling device (attachment plug) . 22 12 Output . 22 12.1 Rated no-load voltage . 22 12.1.1 Rated no-load voltage for arc welding power source . 22 12.1.2 Rated no-load voltage for plasma cutting power source . 23 12.1.3 Additional requirements . 23 12.1.4 Measuring circuit . 24 12.2 Type test values of the conventional load voltage . 25 12.2.1 Manual metal arc welding with covered electrodes . 25 12.2.2 Tungsten inert gas arc welding . 25 12.2.3 Metal inert/active gas and flux cored arc welding . 25 12.2.4 Plasma cutting . 25 12.2.5 Additional requirements . 25 12.3 Mechanical switching devices used to adjust output . 26 12.4 Welding circuit connections . 26 12.4.1 Protection against unintentional contact . 26 12.4.2 Location of coupling devices . 26 SIST EN 60974-6:2016

– 4 – IEC 60974-6:2015 © IEC 2015 12.4.3 Outlet openings . 26 12.4.4 Marking . 26 12.4.5 Connections for plasma cutting torches . 26 12.5 Power supply to external devices . 26 12.6 Auxiliary power output . 26 12.7 Welding cables . 26 13 Control circuits . 26 14 Hazard reducing device . 26 15 Mechanical provisions . 27 15.1 General requirements . 27 15.2 Enclosure . 27 15.2.1 Enclosure materials . 27 15.2.2 Enclosure strength . 27 15.3 Handling means . 27 15.4 Drop withstand . 27 15.5 Tilting stability . 27 16 Auxiliaries . 27 16.1 General . 27 16.2 Wire feeder . 27 16.2.1 General . 27 16.2.2 Test conditions . 27 16.2.3 Thermal requirements . 28 16.2.4 Protection against unintentional contact . 28 16.3 Torch . 28 16.3.1 General . 28 16.3.2 Test conditions . 28 16.3.3 Thermal requirements . 28 16.4 Electrode holder. 28 16.5 Pressure regulator . 28 17 Rating plate . 28 17.1 General requirements . 28 17.2 Description . 28 17.3 Contents . 29 17.4 Tolerances . 31 18 Adjustment of the output . 32 19 Instructions and markings . 32 19.1 Instructions . 32 19.1.1 General . 32 19.1.2 Instruction manual . 32 19.1.3 Safety instructions . 32 19.2 Markings . 33 Annex A (informative)
Test probes . 35 Annex B (informative)
Examples of rating plates . 36 Annex C (informative)
Symbols-only precautionary label . 37 Bibliography . 38
Figure 1 – Measurement of touch current in fault condition . 14 SIST EN 60974-6:2016

IEC 60974-6:2015 © IEC 2015 – 5 – Figure 2 – Measuring network for weighted touch current . 14 Figure 3 – Measurement of r.m.s values . 24 Figure 4 – Measurement of peak values . 25 Figure 5 – Principle of the rating plate . 29 Figure A.1 – Test probe 12 of IEC 61032 . 35 Figure A.2 – Test probe 13 of IEC 61032 . 35 Figure B.1 – Rating plate . 36 Figure C.1 – Example of precautionary label for engine driven manual metal arc welding power source . 37
Table 1 – Temperature limits according to the class of insulation . 17 Table 2 – Maximum temperature limits . 20 Table 3 – Summary of rated no-load voltages . 24 Table 4 – Hazard reducing device requirements
for plasma cutting power source . 27
– 6 – IEC 60974-6:2015 © IEC 2015 INTERNATIONAL ELECTROTECHNICAL COMMISSION ____________
ARC WELDING EQUIPMENT –
Part 6: Limited duty equipment
FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by independent certification bodies. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 60974-6 has been prepared by IEC technical committee 26: Electric welding. This third edition cancels and replaces the second edition published in 2010. It constitutes a technical revision. The main significant technical changes with respect to the previous edition are the following: – modified measurement conditions (see 7.3.1); – improved values for temperature limits according to the class of insulation (see Table 1); – improved maximum temperature limits (see Table 2); – deleted overload test. SIST EN 60974-6:2016

IEC 60974-6:2015 © IEC 2015 – 7 – The text of this standard is based on the following documents: FDIS Report on voting 26/572/FDIS 26/581/RVD
Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. This standard is to be used in conjunction with IEC 60974-1:2012. In this standard, the following print types are used: – conformity statements: in italic type. A list of all the parts in the IEC 60974 series, published under the general title Arc welding equipment, can be found on the IEC website. The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to the specific publication. At this date, the publication will be
• reconfirmed, • withdrawn, • replaced by a revised edition, or • amended.
IMPORTANT – The “colour inside” logo on the cover page of this publication indicates that it contains colours which are considered to be useful for the correct understanding of its contents. Users should therefore print this publication using a colour printer.
– 8 – IEC 60974-6:2015 © IEC 2015 ARC WELDING EQUIPMENT –
Part 6: Limited duty equipment
1 Scope This part of IEC 60974 specifies safety and performance requirements applicable to limited duty arc welding and cutting power sources and auxiliaries designed for use by laymen. Electrically powered equipment is intended to be connected to the single phase public low-voltage supply system. Engine driven power sources cannot exceed output power of 7,5 kVA. NOTE 1 This equipment is typically used by non-professionals in residential areas. This part of IEC 60974 is not applicable to arc welding and cutting power sources that require for operation: • arc striking and stabilizing devices; • liquid cooling systems; • gas consoles; • three-phase input supply; and which are intended for industrial and professional use only. This part of IEC 60974 is not applicable to arc welding and cutting power sources and ancillary equipment used in: • mechanically guided applications; • submerged arc welding process; • plasma gouging process; • plasma welding process; that are covered by other parts of IEC 60974. NOTE 2 Power sources, wire feeders, torches and electrode holders designed for industrial and professional use are respectively covered by IEC 60974-1, IEC 60974-5, IEC 60974-7 and IEC 60974-11. NOTE 3 This part of IEC 60974 does not specify electromagnetic compatibility (EMC) requirements that are given in IEC 60974-10. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60529, Degrees of protection provided by enclosures (IP Code) IEC 60974-1:2012, Arc welding equipment – Part 1: Welding power sources IEC 60974-5:2013, Arc welding equipment – Part 5: Wire feeders IEC 60974-7:2013, Arc welding equipment – Part 7: Torches SIST EN 60974-6:2016

IEC 60974-6:2015 © IEC 2015 – 9 – IEC 60974-10, Arc welding equipment – Part 10: Electromagnetic compatibility (EMC) requirements
IEC 60974-11, Arc welding equipment – Part 11: Electrode holders IEC 61032:1997, Protection of persons and equipment by enclosure – Probes for verification ISO 2503, Gas welding equipment – Pressure regulators and pressure regulators with flow-metering devices for gas cylinders used in welding, cutting and allied processes up to 300 bar (30 MPa) 3 Terms and definitions For the purposes of this document, the terms and definitions given in IEC 60974-1, as well as the following apply: 3.1
touch current electric current passing through a human body or through an animal body when it touches one or more accessible parts of an installation or equipment
[SOURCE: IEC 60050-195:1990/AMD 1:1999, 195-05-21] 3.2
limited duty welding power source power source intended for use by a layman
3.3
layman operator who does not weld in the performance of his profession and has little or no formal instruction in arc welding 3.4
effective supply current I1eff value of the effective input current, calculated from the rated maximum supply current (I1max in A), the supply current at no-load (I0 in A) and the rated maximum welding time in intermittent mode (ONt in s) at the rated maximum welding current during an uninterrupted time of one hour by the formula: −×+×=600316003ON20ON2max11efftItII 3.5
ON time tON period of welding operation as allowed by the thermal control device of the welding power source 3.6
OFF time tOFF period of non-welding operation as imposed by the thermal control device of the welding power source SIST EN 60974-6:2016

– 10 – IEC 60974-6:2015 © IEC 2015 3.7
rated welding time in 1 h ONt summation of the ON times (tON) at the rated maximum welding current in a 60 min period following the first OFF time (tOFF) 3.8
rated continuous welding time ()maxONt ON time (tON) at the rated maximum welding current before the first OFF time (tOFF) 4 Environmental conditions Welding power sources and auxiliaries shall be capable of operating when the following environmental conditions prevail: a) range of ambient air temperature: during operation: –10 °C to +40 °C; b) relative humidity of the air: up to 50 % at 40 °C; up to 90 % at 20 °C; c) ambient air, free from abnormal amounts of dust, acids, corrosive gases or substances etc. other than those generated by the welding process; d) altitude above sea level up to 1 000 m;
e) base of the welding power source inclined up to 10°. Welding power sources and auxiliaries shall withstand storage and transport at an ambient air temperature of –20 °C to +55 °C without any damage to function and performance. Welding power source and auxiliaries shall be capable of delivering the rated continuous welding time and the rated welding time in 1 h at an ambient temperature of 20 °C. 5 Tests 5.1 Test conditions The thermal tests shall be carried out at an ambient temperature of 20 °C, see tolerances in 7.2.2 e). Other tests shall be carried out at an ambient air temperature between 10 °C and 40 °C. 5.2 Measuring instruments See 5.2 of IEC 60974-1:2012. 5.3 Conformity of components See 5.3 of IEC 60974-1:2012. 5.4 Type tests Unless otherwise specified, the tests in this standard are type tests. SIST EN 60974-6:2016

IEC 60974-6:2015 © IEC 2015 – 11 – The welding power source shall be tested with any ancillary equipment fitted that could affect the test results. All type tests shall be carried out on the same welding power source except where it is specified that a test may be carried out on another welding power source. As a condition of conformity the type tests given below shall be carried out in the following sequence with no drying time between f), g) and h): a) general visual inspection, see 3.7 of IEC 60974-1:2012; b) insulation resistance, see 6.1.4 (preliminary check); c) enclosure, see 15.2; d) handling means, see 15.3; e) drop withstand, see 15.4; f) protection provided by the enclosure, see 6.2.1; g) insulation resistance, see 6.1.4; h) dielectric strength, see 6.1.5; i) visual inspection, see 3.7 of IEC 60974-1:2012. The other tests included in this standard and not listed in 5.4 shall be carried out in any convenient sequence. 5.5 Routine tests All routine tests shall be carried out on each welding power source. The following sequence is recommended: a) visual inspection, see 3.7 of IEC 60974-1:2012; b) continuity of the protective circuit, see 10.5.1 of IEC 60974-1:2012; c) dielectric strength, see 6.1.5; d) no-load voltage 1) rated no-load voltage, see 12.1; or 2) for plasma cutting power source, rated reduced no-load voltage, see 13.2.1 of IEC 60974-1:2012; e) test to ensure rated minimum and maximum output values in accordance with 15.4 b) and 15.4 c) of IEC 60974-1:2012. The manufacturer may select conventional load, short circuit load or other test conditions. NOTE In short circuit and other test condition, the output values can differ from conventional load values. 6 Protection against electric shock 6.1 Insulation 6.1.1 General See 6.1.1 of IEC 60974-1:2012. 6.1.2 Clearances See 6.1.2 of IEC 60974-1:2012. 6.1.3 Creepage distances See 6.1.3 of IEC 60974-1:2012. SIST EN 60974-6:2016

– 12 – IEC 60974-6:2015 © IEC 2015 6.1.4 Insulation resistance See 6.1.4 of IEC 60974-1:2012. 6.1.5 Dielectric strength See 6.1.5 of IEC 60974-1:2012. 6.2 Protection against electric shock in normal service (direct contact) 6.2.1 Protection provided by the enclosure 6.2.1.1 General Welding power sources shall have a minimum degree of protection of IP21S using IEC 60529 test procedures and conditions. Remote controls for welding power sources shall have a minimum degree of protection of IP2X using IEC 60529 test procedures and conditions. 6.2.1.2 Protection against ingress of water Adequate drainage shall be provided by the enclosure. Retained water shall not interfere with the correct operation of the equipment or impair safety. Conformity shall be checked as follows: A welding power source shall be subjected to the appropriate water test without being energized. Immediately after the test, the welding power source shall be moved to a safe environment and subjected to the insulation resistance and dielectric strength tests.
Adequate drainage of the enclosure shall be checked by visual inspection. 6.2.1.3 Side and top enclosure openings The enclosure shall be such that a 50 mm long test pin cannot be inserted from all sides except the underside to touch: a) live parts of the input circuit or b) in the case of Class II welding power sources, any metal part which is separated from live parts of the input circuit by basic insulation. Conformity shall be checked with test probe 12 of IEC 61032:1997 (see Figure A.1). 6.2.1.4 Bottom enclosure openings The enclosure shall be such that a 15 mm long test pin cannot be inserted from the underside to touch: a) live parts of the input circuit and b) in the case of Class II welding power sources, any metal part which is separated from live parts of the input circuit by basic insulation. Conformity shall be checked with test probe 13 of IEC 61032:1997 (see Figure A.2). 6.2.2 Capacitors See 6.2.2 of IEC 60974-1:2012. SIST EN 60974-6:2016

IEC 60974-6:2015 © IEC 2015 – 13 – 6.2.3 Automatic discharge of supply circuit capacitors See 6.2.3 of IEC 60974-1:2012. 6.3 Protection against electric shock in case of a fault condition (indirect contact) 6.3.1 Protective provisions See 6.3.1 of IEC 60974-1:2012. 6.3.2 Isolation between windings of the supply circuit and the welding circuit See 6.3.2 of IEC 60974-1:2012. 6.3.3 Internal conductors and connections See 6.3.3 of IEC 60974-1:2012. 6.3.4 Additional requirements for plasma cutting systems See 6.3.4 of IEC 60974-1:2012. 6.3.5 Movable coils and cores See 6.3.5 of IEC 60974-1:2012. 6.3.6 Touch current in fault condition The weighted touch current shall not exceed 7 mA peak in the case of external protective conductor failure or disconnection. Conformity shall be checked using the measuring circuit as shown in Figure 1 and Figure 2 under the following conditions: a) the welding power source is: – isolated from the ground plane; – supplied by the highest rated supply voltage; – not connected to the protective earth except through measurement components; b) the output circuit is in the no-load condition; c) interference suppression capacitors shall not be disconnected. NOTE Caution! A qualified person performs this test. The protective conductor is disabled for this test. SIST EN 60974-6:2016

– 14 – IEC 60974-6:2015 © IEC 2015
Key 1 measuring network 2 power source 3 circuit diagram of Figure 2 A, B connection terminals of measuring network L line N neutral PE protective earth Figure 1 – Measurement of touch current in fault condition
Key A, B test terminals CS 0,22 μF RS 1 500 Ω R1 10 000 Ω RB 500 Ω C1 0,022 μF U1 r.m.s. voltage
weighted touch current (perception/reaction)5002U= (peak value) Figure 2 – Measuring network for weighted touch current
IEC RS RB R1 C1 U2U1ABCS IECIPE PE N/LL 3 A B IOut IIn 12SIST EN 60974-6:2016

IEC 60974-6:2015 © IEC 2015 – 15 – 7 Thermal requirements 7.1 Devices for thermal protection and thermal control A welding power source with limited duty shall be fitted with two independent devices, one for thermal protection and one for thermal control. The thermal control device limits the temperature of its components by reducing or disconnecting the welding current, and is reset automatically and is designed in accordance with Clause 8. The thermal protection defined in Clause 9 shall be designed to operate if the thermal control device fails. 7.2 Heating test 7.2.1 Test conditions The welding power source shall be operated at the rated maximum welding current I2max and conventional load voltage given in 12.2, starting from the cold state. If it is known that I2max does not give the maximum heating, then a worst case test shall additionally be made at the setting within the rated range which gives the maximum heating. When placing the measuring devices, the only access permitted shall be through openings with cover plates, inspection doors or easily removable panels provided by the manufacturer. The ventilation in the test area and the measuring devices used shall not interfere with the normal ventilation of the welding power source or cause abnormal transfer of heat to or from it. NOTE 1 The maximum temperature of components can be reached at the no-load condition. NOTE 2 The rated maximum welding current test and the relevant worst case test can follow each other without waiting for the welding power source to return to the ambient air temperature. 7.2.2 Tolerances of the test parameters During the heating test in accordance with 7.2.3 the following tolerances shall be met: a) load voltage: 510−+ % of the appropriate conventional load voltage; b) welding current: 510−+ % of the appropriate conventional welding current; c) supply voltage: ±5 % of the appropriate rated supply voltage; d) engine speed: 510−+ % of the appropriate rated speed;
e) temperature: 010−+ K of the ambient temperature. 7.2.3 Rated maximum welding current The test sequence for the rated maximum welding current I2max shall be as follows: a) ensure that the welding power source is at thermal equilibrium with the ambient temperature of 20 °C, see tolerances in 7.2.2 e); b) operate the power source at the rated maximum welding current; SIST EN 60974-6:2016

– 16 – IEC 60974-6:2015 © IEC 2015 c) record ON time until first operation of the thermal control device: rated continuous welding time tON (max); d) continue the test immediately after the thermal control device resets, for a duration of 60 min; e) record ON time for each cycle ONt. The test has failed if ONt is less than 30 s or tON (max) is less than 60 s. 7.2.4 Calculation The following rated value shall be calculated: • rated welding time in 1 h ONt at the rated maximum welding current see 7.2.3 e); where ONt is the ON time for each cycle. The minimum value of ONtshall be 60 s. 7.3 Temperature measurement 7.3.1 Measurement condition The temperature rise (K) shall be an average of the maximum and the minimum temperature that occurs during ONt of the last cycle for embedded and surface method or at the end of last ONt for resistance method. The temperature shall be determined as follows: a) for windings, by measurement of the resistance, or by surface or embedded temperature sensors; b) for other parts, by surface temperature sensors. Conformity shall be checked by measuring the temperature during the heating test. All temperatures shall not exceed the maximum temperature given in Table 6 of IEC 60974-1:2012. NOTE 1 The design of limited duty power sources is based on a thermal control device that operates at the maximum allowed temperature as defined by the insulation class. NOTE 2 The surface temperature se
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