IEC 60974-1:2012

IEC 60974-1
®

Edition 4.0 2012-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE


Arc welding equipment –
Part 1: Welding power sources

Matériel de soudage à l’arc –
Partie 1: Sources de courant de soudage

IEC 60974-1:2012

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IEC 60974-1

®


Edition 4.0 2012-06




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE











Arc welding equipment –

Part 1: Welding power sources




Matériel de soudage à l’arc –

Partie 1: Sources de courant de soudage
















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

PRICE CODE
INTERNATIONALE

CODE PRIX XE


ICS 25.160 ISBN 978-2-83220-095-7



Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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– 2 – 60974-1 © IEC:2012
CONTENTS
FOREWORD . 7
1 Scope . 9
2 Normative references. 9
3 Terms and definitions . 10
4 Environmental conditions . 18
5 Tests . 19
5.1 Test conditions . 19
5.2 Measuring instruments . 19
5.3 Conformity of components . 19
5.4 Type tests . 20
5.5 Routine tests . 20
6 Protection against electric shock . 21
6.1 Insulation . 21
6.1.1 General . 21
6.1.2 Clearances . 22
6.1.3 Creepage distances . 23
6.1.4 Insulation resistance . 25
6.1.5 Dielectric strength . 25
6.2 Protection against electric shock in normal service (direct contact) . 26
6.2.1 Protection provided by the enclosure . 26
6.2.2 Capacitors . 27
6.2.3 Automatic discharge of supply circuit capacitors . 27
6.2.4 Isolation of the welding circuit . 28
6.2.5 Welding circuit touch current . 28
6.2.6 Touch current in normal condition . 29
6.3 Protection against electric shock in case of a fault condition (indirect contact) . 29
6.3.1 Protective provisions . 29
6.3.2 Isolation between windings of the supply circuit and the welding circuit . 29
6.3.3 Internal conductors and connections . 29
6.3.4 Additional requirements for plasma cutting systems . 30
6.3.5 Movable coils and cores . 30
6.3.6 Touch current in fault condition . 31
7 Thermal requirements . 31
7.1 Heating test . 31
7.1.1 Test conditions . 31
7.1.2 Tolerances of the test parameters . 32
7.1.3 Duration of test . 32
7.2 Temperature measurement . 32
7.2.1 Measurement conditions . 32
7.2.2 Surface temperature sensor . 32
7.2.3 Resistance . 33
7.2.4 Embedded temperature sensor . 33
7.2.5 Determination of the ambient air temperature . 33
7.2.6 Recording of temperatures . 33
7.3 Limits of temperature rise . 34

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60974-1 © IEC:2012 – 3 –
7.3.1 Windings, commutators and slip-rings . 34
7.3.2 External surfaces . 34
7.3.3 Other components . 35
7.4 Loading test . 35
7.5 Commutators and slip-rings . 36
8 Thermal protection . 36
8.1 General requirements . 36
8.2 Construction . 36
8.3 Location . 36
8.4 Operating capacity . 36
8.5 Operation . 37
8.6 Resetting . 37
8.7 Indication . 37
9 Abnormal operation. 37
9.1 General requirements . 37
9.2 Stalled fan test . 38
9.3 Short circuit test . 38
9.4 Overload test . 38
10 Connection to the supply network . 39
10.1 Supply voltage . 39
10.2 Multi-supply voltage . 39
10.3 Means of connection to the supply circuit . 39
10.4 Marking of terminals . 40
10.5 Protective circuit . 40
10.5.1 Continuity requirement . 40
10.5.2 Type test . 41
10.5.3 Routine test . 41
10.6 Cable anchorage . 42
10.7 Inlet openings . 43
10.8 Supply circuit on/off switching device . 43
10.9 Supply cables . 44
10.10 Supply coupling device (attachment plug). 44
11 Output . 45
11.1 Rated no-load voltage . 45
11.1.1 Rated no-load voltage for use in environments with increased risk of
electric shock . 45
11.1.2 Rated no-load voltage for use in environments without increased risk
of electric shock . 45
11.1.3 Rated no-load voltage for the use with mechanically held torches with
increased protection for the operator . 45
11.1.4 Rated no-load voltage for special processes for example plasma
cutting . 45
11.1.5 Additional requirements . 46
11.1.6 Measuring circuits . 47
11.2 Type test values of the conventional load voltage . 48
11.2.1 Manual metal arc welding with covered electrodes. 48
11.2.2 Tungsten inert gas . 48
11.2.3 Metal inert/active gas and flux cored arc welding . 48
11.2.4 Submerged arc welding . 48

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11.2.5 Plasma cutting . 48
11.2.6 Plasma welding . 48
11.2.7 Plasma gouging . 48
11.2.8 Additional requirements . 48
11.3 Mechanical switching devices used to adjust output . 48
11.4 Welding circuit connections . 49
11.4.1 Protection against unintentional contact . 49
11.4.2 Location of coupling devices . 49
11.4.3 Outlet openings . 49
11.4.4 Three-phase multi-operator welding transformer . 49
11.4.5 Marking . 49
11.4.6 Connections for plasma cutting torches . 50
11.5 Power supply to external devices connected to the welding circuit . 50
11.6 Auxiliary power supply . 50
11.7 Welding cables . 51
12 Control circuits . 51
12.1 General requirement . 51
12.2 Isolation of control circuits . 51
12.3 Working voltages of remote control circuits . 51
13 Hazard reducing device . 51
13.1 General requirements . 51
13.2 Types of hazard reducing devices . 52
13.2.1 Voltage reducing device . 52
13.2.2 Switching device for a.c. to d.c. . 52
13.3 Requirements for hazard reducing devices . 52
13.3.1 Disabling the hazard reducing device . 52
13.3.2 Interference with operation of a hazard reducing device . 52
13.3.3 Indication of satisfactory operation . 53
13.3.4 Fail to a safe condition . 53
14 Mechanical provisions . 53
14.1 General requirements . 53
14.2 Enclosure . 53
14.2.1 Enclosure materials . 53
14.2.2 Enclosure strength . 53
14.3 Handling means . 54
14.3.1 Mechanised handling . 54
14.3.2 Manual handling . 54
14.4 Drop withstand . 55
14.5 Tilting stability . 55
15 Rating plate . 55
15.1 General requirements . 55
15.2 Description . 55
15.3 Contents . 56
15.4 Tolerances . 59
15.5 Direction of rotation . 60
16 Adjustment of the output . 60
16.1 Type of adjustment . 60
16.2 Marking of the adjusting device . 60

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60974-1 © IEC:2012 – 5 –
16.3 Indication of current or voltage control . 60
17 Instructions and markings . 61
17.1 Instructions . 61
17.2 Markings . 62
Annex A (informative) Nominal voltages of supply networks . 63
Annex B (informative) Example of a combined dielectric test . 64
Annex C (normative) Unbalanced load in case of a.c. tungsten inert-gas welding power
sources . 65
Annex D (informative) Extrapolation of temperature to time of shutdown . 67
Annex E (normative) Construction of supply circuit terminals . 68
Annex F (informative) Cross-reference to non-SI units . 70
Annex G (informative) Suitability of supply network for the measurement of the true
r.m.s. value of the supply current . 71
Annex H (informative) Plotting of static characteristics . 72
Annex I (normative) Test methods for a 10 Nm impact . 73
Annex J (normative) Thickness of sheet metal for enclosures . 74
Annex K (informative) Examples of rating plates . 76
Annex L (informative) Graphical symbols for arc welding equipment . 81
Annex M (informative) Efficiency . 104
Annex N (normative) Touch current measurement in fault condition . 105
Bibliography . 109

Figure 1 – Example of insulation configuration for Class I equipment . 21
Figure 2 – Measurement of welding circuit touch current . 28
Figure 3 – Measurement of r.m.s. values . 47
Figure 4 – Measurement of peak values . 47
Figure 5 – Principle of the rating plate . 56
Figure B.1 – Combined high-voltage transformers . 64
Figure C.1 – Voltage and current during a.c. tungsten inert-gas welding . 65
Figure C.2 – Unbalanced voltage during a.c. tungsten inert-gas welding . 66
Figure C.3 – AC welding power source with unbalanced load . 66
Figure I.1 – Test set-up . 73
Figure K.1 – Single-phase transformer . 76
Figure K.2 – Three-phase rotating frequency converter . 77
Figure K.3 – Subdivided rating plate: single-/three-phase transformer rectifier . 78
Figure K.4 – Engine-generator-rectifier . 79
Figure K.5 – Single-/three-phase inverter type . 80
Figure L.1 – Input voltage power switch . 101
Figure L.2 – Arc force control potentiometer . 101
Figure L.3 – Remote receptacle and selector switches . 102
Figure L.4 – Terminals with inductance selector for MIG/MAG welding . 102
Figure L.5 – Process switch (MMA, TIG, MIG) . 102
Figure L.6 – Selector switch on AC/DC equipment . 102
Figure L.7 – Panel indicator lights (overheat, fault, arc striking, output voltage) . 103

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– 6 – 60974-1 © IEC:2012
Figure L.8 – Setting pulsing parameters using digital display . 103
Figure N.1 – Measuring network for weighted touch current . 105
Figure N.2 – Diagram for touch current measurement on fault condition at operating
temperature for single-phase connection of appliances other than those of class II . 107
Figure N.3 – Diagram for touch current measurement on fault condition for three-phase
four-wire system connection of appliances other than those of class II . 108

Table 1 – Minimum clearances for overvoltage category III . 22
Table 2 – Minimum creepage distances . 24
Table 3 – Insulation resistance . 25
Table 4 – Dielectric test voltages . 25
Table 5 – Minimum distance through insulation . 29
Table 6 – Temperature limits for windings, commutators and slip-rings . 34
Table 7 – Temperature limits for external surfaces . 35
Table 8 – Cross-section of the output short-circuit conductor . 38
Table 9 – Current and time requirements for protective circuits . 41
Table 10 – Minimum cross-sectional area of the external protective copper conductor . 41
Table 11 – Verification of continuity of the protective circuit . 42
Table 12 – Pull . 43
Table 13 – Summary of allowable rated no-load voltages . 46
Table 14 – Hazard reducing device requirements. 52
Table E.1 – R
...