IEC 60974-3:2013

Arc welding equipment - Part 3: Arc striking and stabilizing devices

IEC 60974-3:2013 specifies safety requirements for industrial and professional arc striking and arc stabilizing devices used in arc welding and allied processes. This part of IEC 60974 is applicable to stand-alone units which may be connected to a separate welding power source or one where the welding power source and the arc striking and arc stabilizing device are housed in a single enclosure. This third edition cancels and replaces the second edition published in 2007 and constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- changes induced by the publication of IEC 60974-1:2012.
This publication is to be read in conjunction with IEC 60974-1:2012.

Matériel de soudage à l'arc - Partie 3: Dispositifs d'amorçage et de stabilisation de l'arc

L'IEC 60974-3:2013 spécifie les exigences de sécurité pour les dispositifs d'amorçage et de stabilisation industriels et professionnels utilisés en soudage à l'arc et techniques connexes. La présente partie de la CEI 60974 s'applique aux unités indépendantes qui peuvent être soit raccordées à la source de courant de soudage, soit dotées d'une source de courant de soudage et de dispositifs d'amorçage et de stabilisation de l'arc intégrés dans la même enveloppe. Cette troisième édition annule et remplace la deuxième édition parue en 2007 et constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- modifications induites par la publication de la CEI 60974-1:2012.
Cette publication doit être lue conjointement avec la CEI 60974-1:2012.

General Information

• Status: Published
• Publication Date: 25-Nov-2013
• ICS: 25.160.30 - Welding equipment
• Technical Committee: TC 26 - Electric welding
• Drafting Committee: WG 1 - TC 26/WG 1
• Current Stage: DELPUB - Deleted Publication
• Start Date: 28-Apr-2017
• Completion Date: 30-Jan-2019

Relations

• Revised: IEC 60974-3:2019 - Arc welding equipment - Part 3: Arc striking and stabilizing devices
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60974-3


®


Edition 3.0 2013-11



INTERNATIONAL



STANDARD



NORME
INTERNATIONALE


Arc welding equipment –
Part 3: Arc striking and stabilizing devices

Matériel de soudage à l’arc –
Partie 3: Dispositifs d’amorçage et de stabilisation de l’arc



IEC 60974-3:2013

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IEC 60974-3



®



Edition 3.0 2013-11







INTERNATIONAL





STANDARD







NORME



INTERNATIONALE











Arc welding equipment –

Part 3: Arc striking and stabilizing devices




Matériel de soudage à l’arc –

Partie 3: Dispositifs d’amorçage et de stabilisation de l’arc

















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

PRICE CODE
INTERNATIONALE

CODE PRIX R


ICS 25.160 ISBN 978-2-8322-1199-1



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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CONTENTS


FOREWORD . 4

1 Scope . 6


2 Normative references . 6

3 Terms and definitions . 6

4 Environmental conditions . 7

5 Tests . 7

5.1 Test conditions . 7

5.2 Measuring instruments . 7
5.3 Conformity of components . 7
5.4 Type tests . 7
5.5 Routine tests. 7
5.5.1 Stand-alone unit . 7
5.5.2 Built-in unit . 8
6 Protection against electric shock . 8
6.1 Insulation . 8
6.1.1 General . 8
6.1.2 Clearances . 8
6.1.3 Creepage distances . 8
6.1.4 Insulation resistance . 9
6.1.5 Dielectric strength . 9
6.2 Protection against electric shock in normal service (direct contact) . 10
6.3 Protection against electric shock in case of a fault condition (indirect
contact) . 10
6.4 Protective provision . 10
7 Thermal requirements . 10
8 Thermal protection . 10
9 Abnormal operation . 10
10 Connection to the supply network . 11
11 Output . 11
11.1 Rated peak voltage . 11
11.2 Impulse current . 12
11.2.1 Risk of electric shock . 12

11.2.2 Electric charge. 12
11.2.3 Direct contact . 12
11.2.4 Series contact. 13
11.3 Mean energy . 14
11.4 Output circuit capacitance discharging . 15
12 Control circuits . 15
13 Hazard reducing device . 15
14 Mechanical provisions . 15
15 Rating plate . 15
16 Adjustment of the output . 16
17 Instructions and markings . 16
17.1 Instructions . 16
17.2 Markings . 17

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60974-3  IEC:2013 – 3 –


Annex A (informative) Examples of coupling systems for arc striking and stabilizing

devices . 18

Annex B (informative) Example of a rating plate . 19


Bibliography . 20



Figure 1 – Rated peak voltage . 11


Figure 2 – Measurement of electric charge of impulse current . 12

Figure 3 – Measuring circuit for direct contact . 13

Figure 4 – Measuring circuit for serial contact . 14

Figure 5 – Measurement of mean energy . 14
Figure 6 – Measuring circuit for capacitance discharging . 15
Figure A.1 – Examples of coupling systems for arc striking and stabilizing devices . 18
Figure B.1 – Stand-alone unit . 19

Table 1 – Minimum clearances and creepage distances for arc striking and stabilizing
circuits . 9
Table 2 – Maximum peak voltages . 11

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INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________



ARC WELDING EQUIPMENT –



Part 3: Arc striking and stabilizing devices





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
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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 60974-3 has been prepared by IEC technical committee 26:

Electric welding.
This third edition cancels and replaces the second edition published in 2007 and constitutes a
technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
– changes induced by the publication of IEC 60974-1:2012.

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60974-3  IEC:2013 – 5 –


The text of this standard is based on the following documents:


FDIS Report on voting

26/518/FDIS 26/521/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 shall be read in conjunction with IEC 60974-1:2012.
The list of all the parts of IEC 60974, under the general title Arc welding equipment, can be
found on the IEC web site.
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.

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ARC WELDING EQUIPMENT –



Part 3: Arc striking and stabilizing devices








1 Scope


This part of IEC 60974 specifies safety requirements for industrial and professional arc

striking and arc stabilizing devices used in arc welding and allied processes.
This part of IEC 60974 is applicable to stand-alone units which may be connected to a
separate welding power source or one where the welding power source and the arc striking
and arc stabilizing device are housed in a single enclosure.
NOTE 1 Typical allied processes are for example plasma arc cutting and arc spraying.
NOTE 2 This standard does not include electromagnetic compatibility (EMC) requirements.
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 60974-1:2012, Arc welding equipment – Part 1: Welding power sources
IEC 60974-7, Arc welding equipment – Part 7: Torches
IEC 61140, Protection against electric shock – Common aspects for installation and
equipment
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60974-1 and
IEC 60974-7, as well as the following, apply.
3.1
arc striking device
device which superimposes a voltage on the welding circuit to ignite an arc
3.2
arc stabilizing device
device which superimposes a voltage on the welding circuit to maintain an arc
3.3
arc striking voltage
voltage superimposed on the no-load voltage to ignite an arc
3.4
arc stabilizing voltage
voltage superimposed on the arc voltage to maintain the arc

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60974-3  IEC:2013 – 7 –


3.5

arc striking period

period during which the arc striking voltage is superimposed on the no-load voltage


4 Environmental conditions


As specified in IEC 60974-1:2012, Clause 4.


5 Tests


5.1 Test conditions
As specified in 5.1 of IEC 60974-1:2012.
5.2 Measuring instruments
The accuracy of measuring instruments shall be as follows:
a) electrical measuring instruments: class 1 (±1 % of full-scale reading), except for the
measurement of insulation resistance and dielectric strength where the accuracy of the
instruments is not specified, but shall be taken into account for the measurement;
b) thermometer: ±2 K;
c) high-voltage probe: ±5 %.
5.3 Conformity of components
As specified in 5.3 of IEC 60974-1:2012.
5.4 Type tests
As a condition of conformity, the type tests given below shall be carried out on stand-alone
units in the following sequence with no drying time between f), g) and h):
a) general visual inspection, as defined in 3.7 of IEC 60974-1:2012;
b) insulation resistance, as specified in 6.1.4 of IEC 60974-1:2012 (preliminary check);
c) enclosure, as specified in 14.2 of IEC 60974-1:2012;
d) handling means, as specified in 14.3 of IEC 60974-1:2012;
e) drop withstand, as specified in 14.4 of IEC 60974-1:2012;

f) protection provided by the enclosure, as specified in 6.2.1 of IEC 60974-1:2012;
g) insulation resistance, as specified in 6.1.4 of IEC 60974-1:2012;
h) dielectric strength, as specified in 6.1.5 of IEC 60974-1:2012;
i) general visual inspection, as defined in 3.7 of IEC 60974-1:2012.
Rated arc striking and stabilizing peak voltage shall be measured in accordance with 11.1 in
any convenient sequence of type tests but before verifying mechanical provisions.
The other type tests included in this document and not listed here shall be carried out in any
convenient sequence.
5.5 Routine tests
5.5.1 Stand-alone unit
All routine tests shall be carried out on each stand-alone unit in the following sequence:

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a) general visual inspection (as defined in 3.7 of IEC 60974-1:2012);

b) continuity of the protective circuit (as specified in Clause 10 and, if applicable, 10.5.1 of

IEC 60974-1:2012);


c) dielectric strength (as specified in 6.1.5 of IEC 60974-1:2012);

d) high-voltage circuit test: working voltage shall be applied to high-voltage circuits to

establish insulation integrity as specified by the manufacturer;

NOTE No-load voltage and connection of the return cable, either to the ground circuit or isolated, affects

working voltage.

e) general visual inspection (as defined in 3.7 of IEC 60974-1:2012).


5.5.2 Built-in unit
The following routine test shall be carried out on each built-in unit in any convenient sequence
for the power source (as specified in 5.5 of IEC 60974-1:2012):
High-voltage circuit test: working voltage shall be applied to high-voltage circuits to
establish insulation integrity as specified by the manufacturer.
NOTE No-load voltage and connection of the return cable, either to the ground circuit or isolated, affects
working voltage.
6 Protection against electric shock
6.1 Insulation
6.1.1 General
As specified in 6.1.1 of IEC 60974-1:2012.
6.1.2 Clearances
The minimum clearances for high-voltage components shall be in accordance with Table 1.
The minimum clearance for other components shall be in accordance with 6.1.2 of
IEC 60974-1:2012.
Conformity shall be checked by measurement and visual inspection.
6.1.3 Creepage distances
The minimum creepage distances for arc striking and stabilizing circuits shall be in
accordance with Table 1. The minimum creepage distances for other components shall be in
accordance with 6.1.3 of IEC 60974-1:2012.

Conformity shall be checked by measurement and visual inspection.

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60974-3  IEC:2013 – 9 –


Table 1 – Minimum clearances and creepage distances

for arc striking and stabilizing circuits


a b b
Rated peak voltage Clearance Creepage distance

kV mm mm

3 3 6,3

6 5,5 10

8 8 12,5

10 11 16

12 14 20

15 18 25
18 25 30
20 30 35

NOTE These values apply to circuits which are designed in accordance with 11.3.
a
Rated peak voltage shall be measured in accordance with 11.1.
b
Interpolation is allowed.

6.1.4 Insulation resistance
As specified in 6.1.4 of IEC 60974-1:2012.
6.1.5 Dielectric strength
The output circuit of arc striking and stabilizing devices and the insulation of coupling
components (for example, coupling transformers or coupling capacitors) shall withstand an
arc striking test voltage 20 % higher than the rated peak arc striking voltage at the maximum
pulse repetition rate of the device.
Alternatively, an a.c. test voltage with the same peak value of approximately sine waveform at
50 Hz or 60 Hz may be used for coupling components only. The maximum permissible setting
of the tripping current shall be 100 mA. The high voltage transformer shall deliver the
prescribed voltage up to the tripping current. Tripping is regarded as a flashover or a
breakdown.
NOTE 1 For the operator's safety, the lowest setting of the tripping current (less than or equal to 10 mA) is
typical.
Conformity shall be checked by the following test.

Coupling components intended for use with arc striking and stabilizing voltages shall be
subjected to the arc striking test voltage or the a.c. test voltage for 60 s.
NOTE 2 Interference suppression capacitors are not coupling devices.
The output circuit shall be subjected to the arc striking test voltage for 60 s applied between
the point of connection to the welding electrode and
a) exposed conductive parts;
b) other isolated circuits.
Flashover or breakdown shall not occur. Any discharges unaccompanied by a voltage drop
(corona) are disregarded.
NOTE 2 Interference suppression capacitors are subjected to the test of the output circuit.

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6.2 Protection against electric shock in normal service (direct contact)


As specified in 6.2 of IEC 60974-1:2012.


6.3 Protection against electric shock in case of a fault condition (indirect contact)


Stand-alone arc striking and stabilizing device shall be class I or class II equipment in
accordance with IEC 61140, with the exception of the welding circuit.


The output circuit of the arc striking and stabilizing device shall be electrically isolated from
the public supply system by double or reinforced insulation in accordance with the maximum
rated input voltage. Figure A.1 shows examples of coupling systems for arc striking and

stabilizing devices.
Internal conductors and connections shall be secured or positioned as specified in 6.3.3 of
IEC 60974-1:2012.
For Class I stand-alone arc striking and stabilizing device, weighted touch current in the case
of an external protective conductor failure or disconnection shall not exceed the value
specified in 6.3.6 of IEC 60974-1:2012 when energized and not providing the arc striking and
stabilizing voltage.
Conformity shall be checked by visual inspection and by measurement.
6.4 Protective provision
Connection of exposed conductive parts to the protective conductor is not required if the rated
supply voltage is supplied by the welding circuit or SELV.
7 Thermal requirements
Current-carrying components, incorporated in the arc striking and stabilizing device, shall be
capable of carrying the rated welding current as specified by the manufacturer without
a) exceeding the temperature rating of the current-carrying components;
b) causing the surface temperatures, specified in Table 7 of IEC 60974-1:2012, to be
exceeded.
For liquid-cooled apparatus, the test shall be carried out with the minimum flow and the
maximum temperature of the coolant, as recommended by the manufacturer.

Conformity shall be checked by measurement in accordance with 7.2 of IEC 60974-1:2012.
8 Thermal protection
If the arc striking and stabilizing device is designed for use with or built-in a specific welding
power source, the thermal protection tests shall be carried out with the welding power source.
9 Abnormal operation
In the case of a stand-alone arc striking and stabilizing device the abnormal operation tests
defined in Clause 9 of IEC 60974-1:2012 shall be carried out as applicable.
If the arc striking and stabilizing device is designed for use with a specific welding power
source, the abnormal operation tests shall be conducted with the arc striking and stabilizing
device connected to that welding power source.

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60974-3  IEC:2013 – 11 –


The arc stabilizing device shall be short circuited at the output, with neither a torch nor a

return cable connected, until equilibrium is achieved.


Arc striking and stabilizing devices protected internally, for example by automatic shut-off,

meet this requirement if the protection device operates before an unsafe condition occurs.



10 Connection to the supply network


As specified in Clause 10 of IEC 60974-1:2012.


11 Output
11.1 Rated peak voltage
The rated peak voltage (U ) is obtained by subtraction of the no-load voltage (U ) from the
p 0
measured peak voltage (see Figure 1). To determine the peak, the voltage shall be measured
across a 220 pF capacitor with neither a torch nor a return cable connected.
When reported on the rating plate of arc striking and stabilizing devices, the rated peak
voltage (U ) shall be equal to or greater than the measured peak voltage, but shall not exceed
p
the maximum values given in Table 2.



U
U
p
U
0
t
IEC  2836/13


Figure 1 – Rated peak voltage
Table 2 – Maximum peak voltages
Type of torch Peak voltage
Manually guided 15 kV
Mechanically guided or plasma cutting 20 kV

Conformity shall be checked by measurement with an oscilloscope and a high-voltage probe
with sufficient bandw
...