EN ISO 669:2016

SLOVENSKI STANDARD
01-julij-2016
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Resistance welding - Resistance welding equipment - Mechanical and electrical
requirements (ISO 669:2016)
Widerstandsschweißen - Widerstandsschweißeinrichtungen - Mechanische und
elektrische Anforderungen (ISO 669:2016)
Soudage par résistance - Matériel de soudage par résistance - Exigences mécaniques et
électriques (ISO 669:2016)
Ta slovenski standard je istoveten z: EN ISO 669:2016
ICS:
25.160.30 Varilna oprema Welding equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 669
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2016
EUROPÄISCHE NORM
ICS 25.160.30
English Version
Resistance welding - Resistance welding equipment -
Mechanical and electrical requirements (ISO 669:2016)
Soudage par résistance - Matériel de soudage par Widerstandsschweißen -
résistance - Exigences mécaniques et électriques (ISO Widerstandsschweißeinrichtungen - Mechanische und
669:2016) elektrische Anforderungen (ISO 669:2016)
This European Standard was approved by CEN on 2 January 2016.

CEN 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 CEN
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 CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 669:2016 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
European foreword
This document (EN ISO 669:2016) has been prepared by Technical Committee ISO/TC 44 “Welding and
allied processes” in collaboration with Technical Committee CEN/TC 121 “Welding and allied
processes” the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by September 2016, and conflicting national standards
shall be withdrawn at the latest by September 2016.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 669:2016 has been approved by CEN as EN ISO 669:2016 without any modification.

INTERNATIONAL ISO
STANDARD 669
Third edition
2016-02-15
Resistance welding — Resistance
welding equipment — Mechanical and
electrical requirements
Soudage par résistance — Matériel de soudage par résistance —
Exigences mécaniques et électriques
Reference number
ISO 669:2016(E)
©
ISO 2016
ISO 669:2016(E)
© ISO 2016, 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
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

ISO 669:2016(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
3.1 Mechanical parts of spot, projection, and seam welding equipment . 2
3.2 Mechanical parts of upset and flash welding equipment . 8
3.3 Static mechanical characteristics .11
3.4 Electrical and thermal characteristics .14
3.5 Pneumatic and hydraulic characteristics .16
4 Symbols and abbreviated terms .16
5 Physical environment and operating conditions .18
5.1 General .18
5.2 Ambient air temperature .18
5.3 Liquid cooling medium .18
5.4 Humidity .18
5.5 Altitude .19
5.6 Transportation and storage .19
6 Test conditions .19
6.1 General .19
6.2 Environmental conditions .19
6.3 Measuring instruments .19
7 Rated no load voltage at the output .20
7.1 General .20
7.2 a.c. no load voltage (U ) .20
7.3 d.c. no load voltage (U ).20
2d
8 Maximum short circuit current .20
8.1 General .20
8.2 Spot and seam welding equipment .21
8.3 Projection welding equipment .21
8.4 Upset and flash welding equipment .22
9 Thermal rating .23
9.1 General .23
9.2 Thermal test .23
10 Cooling liquid circuit (liquid cooled welding equipment) .23
11 Static mechanical characteristics .24
11.1 General .24
11.2 Spot and projection welding equipment .24
11.2.1 General.24
11.2.2 Eccentricity .25
11.2.3 Angular deflection .26
11.2.4 Radial deflection .26
11.2.5 Axial deflection .27
11.2.6 Machine stiffness .27
11.2.7 Parallelism of top and bottom platen .27
11.2.8 Perpendicularity in platen movement, δ .
4 28
11.3 Seam welding equipment .29
11.3.1 General.29
11.3.2 Eccentricity .29
11.3.3 Angular deflection .30
11.4 Upset welding equipment .30
ISO 669:2016(E)
11.4.1 General.30
11.4.2 Angular deflection .31
12 Rating plate .31
12.1 General .31
12.2 Description .32
12.3 Tolerances .34
13 Instruction manual .34
Annex A (informative) Examples of rating plates .36
Bibliography .38
iv © ISO 2016 – All rights reserved

ISO 669:2016(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 meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 44, Welding and allied processes, Subcommittee
SC 6, Resistance welding and allied mechanical joining.
This third edition cancels and replaces the second edition (ISO 669:2000), which has been technically
revised.
INTERNATIONAL STANDARD ISO 669:2016(E)
Resistance welding — Resistance welding equipment —
Mechanical and electrical requirements
1 Scope
This International Standard defines and specifies certain identified electrical and mechanical
characteristics of equipment used for
— resistance spot welding,
— projection welding,
— resistance seam welding,
1)
— upset welding , and
2)
— flash welding .
This International Standard specifies the information to be given in equipment specifications and the
test methods to be used for measuring those characteristics.
Not all requirements apply to all types of equipment.
The following types of power sources are included:
— single phase with alternating welding current;
— single phase with rectified welding current by rectification of the output of the welding transformer;
— single phase with inverter welding transformer;
— three phase with rectified welding current by rectification of the output of the welding transformer;
— three phase with a current rectification in the input of the welding transformer (sometimes called
frequency convertor);
— three phase with inverter welding transformers.
This International Standard does not apply to welding transformers that are separate from the
equipment.
NOTE Safety requirements for resistance welding equipment are covered by IEC 62135–1.
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.
ISO 5826:2014, Resistance welding equipment — Transformers — General specifications applicable to all
transformers
ISO 17657-2, Resistance welding — Welding current measurement for resistance welding — Part 2: Welding
current meter with current sensing coil
1) Often referred to by the non-preferred term, butt welding.
2) Often referred to by the non-preferred term, flash butt welding.
ISO 669:2016(E)
ISO 17657-5, Resistance welding — Welding current measurement for resistance welding — Part 5:
Verification of welding current measuring system
ISO 17677-1, Resistance welding — Vocabulary — Part 1: Spot, projection and seam welding
IEC 62135-1, Resistance welding equipment — Part 1: Safety requirements for design, manufacture and
installation
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 17677-1 and the following apply.
3.1 Mechanical parts of spot, projection, and seam welding equipment
3.1.1
arm
device for transmitting the electrode force (3.1.16) which can also conduct the welding current or
support a separate conductor
Note 1 to entry: See Figure 1 and Figure 3.
3.1.2
welding head
device comprising the force generation and guiding system carrying an electrode holder (3.1.3), platen
(3.1.5), or seam welding head (3.1.6) mounted to the upper arm or directly to the machine body
Note 1 to entry: See Figure 1.
3.1.3
electrode holder
device holding a spot welding electrode (3.1.4) or an electrode adaptor
[SOURCE: ISO 8430-1, ISO 8430-2, and ISO 8430-3]
Note 1 to entry: See Figure 1.
2 © ISO 2016 – All rights reserved

ISO 669:2016(E)
a)  Spot welding equipment b)  Projection welding equipment
c)  Longitudinal seam welding equipment d)  Transverse seam welding equipment
e)  Rocker arm welding equipment
ISO 669:2016(E)
f)  Welding gun without transformer g)  Manual gun with integrated transformer
h)  Robot mount C-gun
Key
1 force generation system 5 frame 9 platen
2 moveable arm 6 transformer 10 seam welding head
3 welding head 7 electrode holder 11 electrode wheel
4 stationary arm 8 spot welding electrode 12 electrode adapter
Figure 1 — Elements of spot, projection, and seam welding equipment
1 1
2 2
3 34
Key
1 clamping device
2 clamping die
3 current-carrying clamping die
4 © ISO 2016 – All rights reserved

ISO 669:2016(E)
4 slide drive
5 slide
6 welding transformer
Figure 2 — Elements of upset welding equipment
a) Arm length fixed b)  Arm length adjustable
Figure 3 — Arms (lower arms)
3.1.4
spot welding electrode
electrode designed for spot welding
[SOURCE: ISO 5184 and ISO 5821]
Note 1 to entry: See Figure 1.
3.1.5
platen
device normally having tee slots and carrying projection welding electrodes or welding tools
[SOURCE: ISO 865]
Note 1 to entry: See Figure 1.
3.1.6
seam welding head
device comprising an electrode wheel bearing (3.1.7) and mounted on the upper and lower arm for
longitudinal and/or transversal seam welding
Note 1 to entry: See Figure 1.
3.1.7
electrode wheel bearing
device guiding the electrode wheel (3.1.8) for force transfer and mostly for current transfer
3.1.8
electrode wheel
electrode as a rotating disc
Note 1 to entry: See Figure 1.
Note 2 to entry: This device can be driven by a motor or moved by the workpiece (idler wheels). The driver can be
direct to the electrode shaft or to its circumference (knurl drive) (see Figure 6).
3.1.9
electrode wheel profile
form of the electrode wheel (3.1.8) being single- or double-sided bevelled or radiused depending on the
welding conditions and access
Note 1 to entry: See Figure 5.
ISO 669:2016(E)
3.1.10
electrode wheel speed
rotational speed, n, of the electrode wheel (3.1.8)
Note 1 to entry: See Figure 4.
3.1.11
electrode wheel speed
linear tangential speed, v, of the electrode wheel (3.1.8) at the circumference
Note 1 to entry: See Figure 4.
3.1.12
throat gap
e
usable distance between the arms (3.1.1) or the outer current
conducting parts of the welding circuit
Note 1 to entry: See Figure 6.
3.1.13
platen distance
e
clamping distance between the platens (3.1.5)
Note 1 to entry: See Figure 6.
Note 2 to entry: See also die distance (3.2.11).
3.1.14
throat depth
l
usable distance from the centre of the platens (3.1.5) or the axes of the electrodes or, in the case of
oblique electrodes, the point of intersection of the electrode axes in the working position or the contact
line of electrode wheels (3.1.8) and that part of the equipment body located closest to it
Note 1 to entry: See Figure 6.
Note 2 to entry: This definition does not consider any offset of the electrode tips.
a)  Direct drive b)  Knurl drive c)  Idler wheels
6 © ISO 2016 – All rights reserved

ISO 669:2016(E)
Key
1 electrode wheel
2 workpieces to be welded
Figure 4 — Drive types of electrode wheels
a)  Bevelled b)  Radiused
Figure 5 — Electrode wheel profiles
l l
a)  Spot welding equipment b)  Projection welding equipment
c)  Upset welding equipment (top view) d)  Seam welding equipment
Key
e throat gap
l throat depth
Figure 6 — Main dimensions
3.1.15
electrode stroke
c
physical displacement of electrodes during process function
Note 1 to entry: When the electrode is attached to the force generation system, the stroke of both the electrode
and the driving cylinder is equal.
l
e
e
ISO 669:2016(E)
Note 2 to entry: When the moving electrode is attached to a hinged lever moved by a force generation system, the
maximum stroke of the electrode by convention equals the length of the chord of the arc generated by the tip of
the moving electrode for the full stroke of the driving cylinder.
Note 3 to entry: The stroke of the electrode may be composed of a “work clearance stroke” without any contact,
facilitating the introduction of the workpiece between the electrodes and a smaller “working stroke”.
3.1.16
electrode force
F
force to the workpiece transmitted by the electrodes
3.1.17
maximum electrode force
F
max
maximum electrode force which can be generated by the welding equipment without permanent
damage to its mechanical parts
3.1.18
minimum electrode force
F
min
minimum electrode force which can be used for proper functioning of the welding equipment
3.2 Mechanical parts of upset and flash welding equipment
3.2.1
slide drive
drive generating and transferring the movements and upset forces necessary for welding to a workpiece
located in the clamping device (3.2.2)
Note 1 to entry: See Figure 2.
Note 2 to entry: For flash welding, the drive may be required to reciprocate the slide for preheating by following
the flashing movement and to provide the upset force.
3.2.2
clamping device
device generating the contact force necessary for current flow and providing the clamping force (3.2.13)
necessary to withstand the upset force if no supplementary clamping devices (3.2.3) or backstops (3.2.4)
are used
Note 1 to entry: See Figure 2.
3.2.3
supplementary clamping device
non-current carrying device to provide the clamping force (3.2.13) necessary to resist the upset force
3.2.4
backstop
device to support the total or a part of the upsetting force (3.2.15) to a workpiece in order to prevent a
workpiece from sliding during upsetting
3.2.5
clamping die
device designed to transfer all forces to the workpiece in contacting with its clamping face
Note 1 to entry: See Figure 2 and Figure 7.
8 © ISO 2016 – All rights reserved

ISO 669:2016(E)
1 1
a)  Flat b)  Prism c)  Cylindrical d) Profile
Key
1 mounting or support face
2 contact and/or clamping face
Figure 7 — Types of clamping dies (illustrated in upsetting direction)
3.2.6
die length
G
usable length of a clamping die (3.2.5) in the upsetting direction
Note 1 to entry: See Figure 8.
3.2.7
die width
W
usable width of a clamping die (3.2.5) perpendicular to the upsetting and clamping direction
Note 1 to entry: See Figure 8.
3.2.8
die thickness
δ
dimension of the die in the clamping direction
Note 1 to entry: See Figure 8.
3.2.9
die stroke
q
difference between the smallest and largest opening gap (3.2.10)
Note 1 to entry: See Figure 8.
3.2.10
opening gap
f
usable distance between flat clamping faces
Note 1 to entry: See Figure 8.
Note 2 to entry: If the workpiece has to be loaded perpendicular to the upsetting direction, the usable gap of
profile dies is smaller than flat dies (see Figure 7).
3.2.11
die distance
e
distance between both die pairs in the upsetting direction
Note 1 to entry: See Figure 8.
ISO 669:2016(E)
3.2.12
throat depth
l
distance perpendicular to the direction of the upsetting force (3.2.15) between the machine body and
the outer edge of the clamping dies (3.2.5)
Note 1 to entry: See Figure 6 and Figure 8.
Note 2 to entry: See also throat gap (3.1.12).
a)  View perpendicular to clamping and b)  View in upsetting direction
upsetting direction
Key
G die length
e die distance
δ die thickness
W die width
l throat depth
q die stroke
f minimum opening gap
min
f maximum opening gap
max
a
Upsetting direction.
b
Clamping direction.
Figure 8 — Upset and flash welding equipment dimensions
3.2.13
clamping force
F
force applied to the workpiece by the clamping dies (3.2.5)
3.2.14
maximum clamping force
F
2max
maximum force the equipment is capable of providing to prevent any sliding and to maintain good
electrical contact with the electrodes
3.2.15
upsetting force
F
force acting in the upsetting direction to press the workpieces together
10 © ISO 2016 – All rights reserved

ISO 669:2016(E)
3.2.16
maximum upsetting force
F
1max
maximum upsetting force which can be generated by the welding equipment without damage to its
mechanical parts
3.2.17
minimum upsetting force
F
1min
minimum upsetting force which can be used for proper functioning of the welding equipment
3.3 Static mechanical characteristics
3.3.1
contact fault
fault relating to the eccentricity (3.3.2) and deflection
3.3.2
eccentricity
g
distance to which the central points of the electrode working faces or the clamping platens are displaced
in relation to each other by the electrode force (3.1.16)
Note 1 to entry: See Figure 9 and Figure 10.
Note 2 to entry: The eccentricity of spot and seam welding equipment (see Figure 9) is calculated by the following
formula:
g = b – a
Note 3 to entry: The eccentricity of projection welding equipment (see Figure 10) is measured in accordance
with 11.2.2.
3.3.3
angular deflection
α
difference between the angular position, α , unloaded of the electrode axes, the clamping platen faces,
or the workpiece axes and the angular position, α under load
2,
Note 1 to entry: α may be zero by design.
Note 2 to entry: See Figure 9 to Figure 11.
Note 3 to entry: The angular deflection of spot and seam welding equipment (see Figure 9) is calculated by the
following formula:
α = α − α
2 1
Note 4 to entry: The angular deflection of projection welding equipment (see Figure 10) is calculated by the
following formula:
 
bb−
 


α = arctan



 b 
 
Note 5 to entry: The angular deflection of upset welding equipment (see Figure 11) is calculated by the following
formula:
 
b


α = arctan 





k
 
α
90°
ISO 669:2016(E)
Key
h axial deflection - unloaded b length for determination of the contact fault
h axial deflection - loaded g eccentricity (b - a)
h axial deflection (h – h ) α angular position - unloaded
1 0 1
r radial deflection - unloaded α angular position - loaded
0 2
r radial deflection - loaded 1 reference measurement point
r radial deflection (r – r ) 2 electrodes - loaded by F
1 0
a length for determination of the contact fault 3 electrodes - unloaded
Figure 9 — Contact fault of spot and seam welding equipment
Figure 10 — Contact fault of projection welding equipment
Figure 11 — Contact fault of upset welding equipment
12 © ISO 2016 – All rights reserved
90°
α
b
b
b
ISO 669:2016(E)
3.3.4
radial deflection
r
displacement, normal to the direction of the electrode force (3.1.16), to which the central point of the
electrode working face or a platen (3.1.5) is displaced by the application of the electrode force
Note 1 to entry: See Figure 9.
Note 2 to entry: The difference between radial deflection values r1 (electrode 1) and r2 (electrode 2) is equal to
the value of eccentricity (3.3.2).
3.3.5
axial deflection
h
displacement of the central point of the electrode in the direction of the electrode force (3.1.16) as a
result of the application of the electrode force
Note 1 to entry: See Figure 9.
3.3.6
machine stiffness
K
displacement or extension of the force generation system when the maximum electrode force, F ,
max
(3.1.17) is applied
Note 1 to entry: See 11.2.6.
Note 2 to entry: Not to be confused with stiffness as a function of force divided by displacement.
3.3.7
maximum angular displacement between top and bottom platen
δ
in projection welding, the maximum angle between the surfaces of the top and bottom platens (3.1.5) in
two axes parallel and perpendicular to the throat of the machine
Note 1 to entry: See Figure 17 and Figure 18.
3.3.8
perpendicularity in movement of top and bottom platen
δ
in projection welding, the variation in perpendicularity between the trajectory of the movable top
platen and the bottom platen when used as a reference measured in three dimensions (i.e. to the right
and left and at the front and rear of the platen (3.1.5))
Note 1 to entry: See Figure 12.
δ₄
Figure 12 — Perpendicularity in movement of top platen (projection welding)
ISO 669:2016(E)
3.4 Electrical and thermal characteristics
3.4.1
duty
schedule of the operating conditions of equipment (their respective durations and sequences)
3.4.2
continuous duty
duty (3.4.1) corresponding to a permanent on load operation without any interruption, in which case,
the duty factor (3.4.4) is 100 %
3.4.3
periodic duty
repeated identical cycles of a constant load and a no load time with the sum of one load time and one no
load time being the weld cycle time
Note 1 to entry: This International Standard considers the load to be constant, i.e. without any preheating and/or
post heating period.
3.4.4
duty factor
X
ratio for a given interval of the on load duration to the total time
Note 1 to entry: This ratio, lying between 0 and 1, can be expressed as a percentage.
3.4.5
rated input voltage
U
1N
input voltage for which the equipment is constructed
3.4.6
rated no load voltage
U or U
20 2d
3.4.7
a.c. no load voltage
U
voltage of one output winding of the transformer when the external circuit is open and the rated input
voltage (3.4.5) is applied to the input terminals
Note 1 to entry: Several settings of the input winding result in relevant values of the no load voltage.
3.4.8
d.c. no load voltage
U
2d
measured maximum output voltage when operating under no load
conditions with the rated input voltage (3.4.5) applied to the input terminals
Note 1 to entry: See 7.3.
3.4.9
permanent input current
I or I
1p Lp
input current corresponding to the permanent output current (3.4.10)
Note 1 to entry: The relationship between input and output currents depend on the type of welding equipment.
Note 2 to entry: I is used for single phase equipment while I is used for three phase equipment.
1p Lp
14 © ISO 2016 – All rights reserved

ISO 669:2016(E)
3.4.10
permanent output current
I
2p
highest output current on all settings of the regulator for continuous operation
[SOURCE: 100 % duty factor (3.4.4)]
Note 1 to entry: This parameter is used to characterize the performance of the equipment, but is not an operating
condition except for seam welding.
3.4.11
permanent power
S
p
maximum electrical input power for 100 % duty factor (3.4.4) without the equipment exceeding the
specified temperature rise
Note 1 to entry: This parameter is used to characterize the performance of the equipment, but is not an operating
condition except for seam welding.
3.4.12
maximum time per impulse
t
i
time during which the output current may flow without interruption at a given output current or
voltage adjustment
Note 1 to entry: This time is limited
— by the saturation of the magnetic circuit for welding equipment with rectification of the input, or
— by the heat rise of the rectifier for welding equipment with rectification of the output.
3.4.13
maximum short circuit current input
I or I
1cc Lcc
root mean square (rms) value of the current at rated input voltage (3.4.5) at the highest output
voltage tapping
Note 1 to entry: The electrodes being short circuited in accordance with Clause 8 and the two values given
correspond to the minimum and maximum values of the impedance compatible with this method of short circuit.
Note 2 to entry: I is used for welding equipment with rectification.
Lcc
3.4.14
maximum short circuit output current
I
2cc
root mean square (rms) value of the current at rated input voltage (3.4.5) at the highest output
voltage tapping
Note 1 to entry: The electrodes being short circuited in accordance with Clause 8 and the two values given
correspond to the minimum and maximum values of the impedance compatible with this method of short circuit.
3.4.15
input power at 50 % duty factor
S
maximum electrical input power for 50 % duty factor (3.4.4) without the equipment exceeding the
specified temperature rise calculated by the following formula:
S = S 2
50 p
ISO 669:2016(E)
3.5 Pneumatic and hydraulic characteristics
3.5.1
supply pressure
p
pressure of the energizing medium at the supply point of the welding equipment
3.5.2
minimum supply pressure
p
1min
minimum pressure at the supply point of the welding equipment to obtain the maximum electrode force
(3.1.17)
3.5.3
maximum supply pressure
p
1max
maximum pressure allowable at the supply point of the welding equipment
3.5.4
rated cooling liquid flow
Q
total quantity of cooling liquid to operate the equipment at permanent power (3.4.11) without exceeding
the temperature rise limits
3.5.5
cooling liquid pressure drop
Δ
p
pressure drop at the rated cooling liquid flow (3.5.4)
4 Symbols and abbreviated terms
The symbols used in this International Standard are listed in Table 1.
Table 1 — Symbols and their designations
Symbol Designation Reference
a length for determination of the contact fault 3.3.1, Figure 9
a a lengths for determination of the angular deflection 11.3
1, 2
b length for determination of the contact fault 3.3.1, Figure 9, Figure 10
b b b lengths for determination of the contact fault 3.3.1, 11.2.3, 11.3.3, 11.4.2,
1, 2, 3
Figure 10
c electrode stroke 3.1.15, 11.1
d diameter of the tip of electrode or width of the electrode 8.2
wheels
d disc diameter 11.2.3
k
D ball diameter 11.2.1
e 1)  throat gap 3.1.12, 3.1.13, 8.4, 11.1, 12.3
2)  platen distance 3.1.13, 12.2
3)  die distance 3.2.11, 8.4, 12.3
e’ distance for calculation of the length of copper bar 8.3
f opening gap 3.2.10
f maximum opening gap 3.2.13
max
f minimum opening gap 3.2.13
min
F electrode force 3.1.16, 8.4
16 © ISO 2016 – All rights reserved

ISO 669:2016(E)
Table 1 (continued)
Symbol Designation Reference
F maximum electrode force 3.1.17, 8.2, 8.3, 11.1, 12.3, 13
max
F minimum electrode force 3.1.18, 12.3
min
F upsetting force 3.2.15
F maximum upsetting force 3.2.16, 8.4, 11.1, 12.3, 13
1max
F minimum upsetting force 3.2.17, 12.3, 13
1min
F clamping force 3.2.13
F maximum clamping force 3.2.14, 8.4, 11.4, 12.3, 13
2max
F minimum clamping force 12.3, 13
2min
F ′, F ′ opposite forces 11.2.3
1 2
g eccentricity 3.3.2, 11.1, 11.2.2, 11.3.2,
12.3,
Figure 9, Figure 10
g g g eccentricity at 10 %, 50 % or 100 % of the maximum force 12.3
10, 50, 100
G die length 3.2.6, Figure 8
h axial deflection 3.3.5, 11.2.5, Figure 9
h axial deflection - unloaded Figure 9
h axial deflection – loaded Figure 9
I maximum short circuit current input 3.4.13, 8, 13
1cc
I permanent input current 3.4.9, 9.1, 13
1p
I input current at a given duty factor 3.4.14
1X
I maximum short circuit output current 3.4.14, 12.3, 13
2cc
I permanent output current (100 % duty factor) 3.4.11, 9.1, 9.2, 12.3, 13
2p
I maximum short circuit current input 3.4.15, 13
Lcc
I permanent input current 3.4.10, 9.1, 9.2, 13
Lp
k distance for determination of angular deflection 3.3.3, 11.3, 11.4, Figure 11
K machine stiffness 3.3.6, 11.2.6
l throat depth 3.1.14, 3.1.16, 3.2.13, 11.1,
12.3
L short circuit length of copper bar 8.4, 11.4
sc
L length of copper bar 8.3
12.3, Annex A
m mass of the welding equipment
n (rotational) electrode wheel speed 3.1.10, 12.3
p supply pressure 3.5.1
p minimum supply pressure 3.5.2, 12.3, 13
1min
p maximum supply pressure 3.5.3, 12.3, 13
1max
q die stroke 3.2.9, Figure 8
Q rated cooling liquid flow 3.5.4, 10, 12.3, 13
r radial deflection 3.3.4, 11.2.4, Figure 9
r radial deflection – unloaded Figure 9
r radial deflection – loaded Figure 9
S permanent power (100 % duty factor) 3.4.11, 9.1, 9.2, 12.3
p
S input power at 50 % duty factor 3.4.15 ,12.2
t maximum time per impulse 3.4.12
i
U rated input voltage 3.4.5, 7, 9.2, 12.3, 13
1N
U′ input voltage 7
1N
ISO 669:2016(E)
Table 1 (continued)
Symbol Designation Reference
U rated a.c. no-load voltage 3.4.6, 3.4.7, 7, 12.3, 13
U′ a.c. no-load voltage 7
U rated d.c. no-load voltage from inverter type welding 3.4.8, 3.4.9, 7, 7.1, 12.3, 13
2d
equipment
v (linear tangential) electrode wheel speed 3.1.11, 12.3
W die width 3.2.7, Figure 8, 8.4
X duty factor 3.4.4, 3.4.14
α angular deflection 3.3.3, Figure 10, Figure 11,
11.1, 11.2.3, 11.4.2, 12.3
α α angular positions for determination of the angular deflection 3.3.3, 11.3.3, Figure 9
1, 2
...