Telwin PTE 28 LCD - Spot Welding; Preliminary Operations; Adjusting the Parameters; Procedure

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4.3.2“START”button
Thispush-buttonmustbepressedtocontrolweldingineachofthefollowingconditions:
- everytimethemainswitchhastripped(pos.“O”=>pos.“I”);
- eachtimethesafety/protectiondevicescutin;
- whenthepowersupplyisreinstated(electricityandcompressedair)followinga
shutdownofpowersuppliesoramalfunction.
ATTENTION! PERIODICALLY MAKE SURE THE SAFE START
FUNCTIONOPERATESCORRECTLY.
4.3.3NOWELDING/WELDINGcycleswitch
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NOWELDING:allowsuseofthespotweldingmachinewithoutwelding.Itis
usedtomovethearmsandclosetheelectrodeswithoutcurrentsupplies.
RESIDUALRISK!Thisoperatingmodealsocausestheresidualrisk
ofcrushingoftheupperlimbs:takeallnecessaryprecautions(see
safety chapter).
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WELDING(normalweldingcycle):allowsthespotweldingmachinetoperform
welding operations.
4.3.4 Thermal protection switch (AL1)
Thisistriggeredbyoverheatingofthespotweldingmachineduetolowcapacityor
totallackofcoolingwater,orbyaworkcycle(DUTYCYCLE)thatexceedstheallowed
thermal threshold.
ThetriggeredswitchissignalledbytheiconinFIG.D2-9andtheAL1iconswitching
on.
EFFECT:currentblock(weldinginhibited).
RESET:manual(usingthe“START”button)afterthemachinetemperaturefallswithin
the allowed threshold (the AL1 icon will switch off and the “START” icon will switch on).
4.3.5 Compressed air safety switch (AL6 - PCP mod. only)
Thisistriggeredbylackoforlowpressure(p<2.5÷3bar)ofthecompressedair
supply;thetriggeredswitchisindicatedonthepressuregauge(0÷3bar)andtheAL6
icononthedisplay.
EFFECT:allmovementisblocked,theelectrodesopen(exhaustercylinder);poweris
shutdown(weldinginhibited).
RESET:manual(usingthe“START”button)afterthemachinepressurefallswithinthe
allowedthreshold(“START”indicationonthedisplay).
4.3.6 Overvoltage and undervoltage trip switch (AL3 and AL4).
This is triggered by an excessive overvoltage or undervoltage of the electricity
supply;thetriggeredswitchisindicatedonthedisplaybyAL3(overvoltage)andAL4
(undervoltage).
EFFECT:allmovementisblocked,exhaustercylinder(ifinstalled);powerisshutdown
(welding inhibited).
RESET:manual(usingthe“START”button)afterthemachinepressurefallswithinthe
allowedvoltagelimits(“START”indicationonthedisplay).
5. INSTALLATION
WARNING! CARRY OUT ALL INSTALLATION OPERATIONS AND
ELECTRICAL AND PNEUMATIC CONNECTIONS WITH THE SPOT-WELDER
COMPLETELY SWITCHED OFF AND DISCONNECTED FROM THE POWER
SUPPLYOUTLET. THEELECTRICALAND PNEUMATIC CONNECTIONS MUST
BEMADEONLYANDEXCLUSIVELYBYAUTHORISED,SKILLEDPERSONNEL.
5.1PRELIMINARYOPERATIONS
Unpackthespot-welder,assembletheseparatepartsasindicatedbelow.
5.2LIFTINGTHESPOT-WELDER (FIG. E)
Thespot-weldershouldbeliftedwithadoublecableandhooks,usingtheeyebolts
ttedforthispurpose.
Itisabsolutelyprohibitedtoslingthespot-welderinadifferentwayfromtheonewe
prescribed (e.g. on arms or electrodes).
5.3 POSITION
The installation area must be sufciently large and without obstacles, suitable for
ensuringsafeaccesstothecontrolpanelandtotheworkarea(electrodes).
Ensurethattherearenoobstaclesnearthecoolingairinletsandoutletsandthatno
conductivedusts,corrosivevapour,humidity,etc.canbesuckedin.
Position the spot-welder ona plane surface made of homogeneous and compact
material(oormadeofconcreteorsimilarphysicalcharacteristics).
Fasten the spot-welder to theoor bymeans offour M10bolts, usingthe special
holesonthebase;eachindividualelementanchoringthespot-weldertotheoormust
guaranteeatensilestrengthofatleast60Kg.(60daN).
Maximum load
The maximum load that can be applied to the lower arm (concentrated on the
electrode axis) is 35 Kg. (35daN).
5.4CONNECTIONTOTHEMAINPOWERSUPPLY
5.4.1Warnings
- Beforemakinganyelectricalconnection,checktheratingplatedataonthespot
weldertomakesuretheycorrespondtothevoltageandfrequencyoftheavailable
powersupplywherethemachineistobeinstalled.
- Thespotweldermustbeconnectedonlyandexclusivelytoapowersupplywiththe
neutralconductorconnectedtoearth.
- To guarantee protection against any direct contact always use the differential
switches indicated below:
 -TypeA(
)forsingle-phasemachines;
 -TypeB(
)forthree-phasemachines;
- Inorder tosatisfytherequirementsoftheEN61000-3-11 (Flicker)standardwe
recommend connecting the spot welder to interface points of the main power
supplythathaveanimpedanceoflessthanZmax=0.066ohm.
- ThespotwelderdoesnotfallwithintherequisitesofIEC/EN61000-3-12standard.
 Shoulditbeconnectedtoapublicmainssystem,itistheinstaller’sresponsibility
to verify that the spot welding machine itself is suitable for connecting to it (if
necessary,consultthedistributionnetworkcompany).
5.4.2 Connecting the power supply cable to the spot-welder (FIG. F)
Removetherightsidepanel,assemblethesuppliedcableclipattheholedrilledon
thebackpanel.
Passthepowersupplycablethroughthecableclipandconnectittothepowersupply
block(phasesL1(N)L2)andtothescrewterminaloftheyellow-greenearthprotection
conductor.
Dependingontheterminalblockmodel,tthecableterminalsasshowninthediagram
(FIG. F1, F2).
Blockthecablebytighteningthescrewsonthecableguide.
See the “TECHNICAL DATA” paragraph for the minimum allowed section of the
conductors.
5.4.3 Plug and socket
Connectanormalizedplugtothepowercable(3P+T:only2polesareusedforthe
400V INTERPHASE SYSTEM connection; 2P+T: 230V INTERPHASE connection)
of appropriate capacity and prepare a power supply outlet tted with fuses or an
automaticcircuit-breaker;thecorresponding earth terminalshould beconnectedto
the(yellow-green)earthconductorofthepowersupply.
Thecapacityandinterventioncharacteristicsofthefusesandcircuit-breakerswitch
are given in the paragraph “OTHER TECHNICAL DATA” and/or in TAB. 1.
Shouldtwoormorespotweldersbeinstalled,distributethepowersupplycyclically
betweenthethreephasesinordertocreateamorebalancedload;forexample:
spotwelder1:powersupplyL1-L2;
spotwelder2:powersupplyL2-L3;
spotwelder3:powersupplyL3-L1.
WARNING!Failuretoobservetherulesgivenabovewillinvalidatethe
(class I) safety system provided by the manufacturer causing serious risks to
people(e.g.electricshock)andobjects(e.g.re).
5.5 PNEUMATIC CONNECTION (FIG. G) (PCP mod. only)
- Prepareacompressedairsupplylinewithaworkingpressureofatleast6bar.
- Connectthegaspipetting,suppliedasanaccessory,tothe1/8gascouplingin
FIG.G-1;useteontapetoguaranteeairtightsealing.
- Connectacompressedairhoseofanadequatesizeforthettingused);usea
suitablecliporcollartoguaranteeairtightsealing.
5.6 CONNECTING THE COOLING CIRCUIT (FIG. H)
Itisnecessarytosetupawaterdeliverypipeformaximumtemperature30°C,with
minimumowratenotlessthanthatspeciedinTECHNICALDATA.Itispossibleto
setupanopencoolingcircuit(discardingthereturnwater)oraclosedcircuitaslong
asthetemperatureandwaterowrateparametersarerespected.
Connectthewaterttingssuppliedasaccessoriestothe1/8gascouplingsinFIG.H:
thewatercouplingsarettedwith“OR”sealingringsanddonotrequiretheapplication
ofteontape.
Connectthewaterdeliverypipe(FIG.H-1)totheexternalwaterchannelling,checking
forcorrectoutowandthecapacityofthereturnpipe(FIG.H-2);useasuitableclipor
collartoguaranteeairtightsealing.
WARNING!Weldingoperationsperformedwithoutorwithinsufcientwater
owcouldcausethespot-weldertobreakdownduetooverheating.
6.SPOTWELDING
6.1PRELIMINARYOPERATIONS
Beforecarryingoutanyspot-welding operationit isnecessary tomake aseries of
checksandadjustments,whichshouldbecarriedoutwiththegeneralswitchinthe“O”
position(withthepadlockclosedinPCPversions)andwiththecompressedairsupply
switched off (DISCONNECTED).
- Ensurethattheelectricconnectionisdoneaccordingtothepreviousinstructions.
- Putthecoolingwaterintocirculation.
- Adjustdiameter”d”oftheelectrodecontactsurfaceaccordingtothethickness”s”
ofthesheettobespotwelded,accordingtorelationshipd=4÷6·√s.
- Betweentheelectrodesslideashimequivalenttothethicknessofthesheettobe
spotwelded;ensurethatthearms,broughttogethermanually,areparallelandthat
the electrode holders are centred.
 Ifnecessary,makesomeadjustmentsbylooseningtheelectrodeholderlocking
screwsuntilyoundthemostsuitablepositionforthejobtobeperformed;secure
thelockingscrewstightly.
 InmodelsPTEandPCP28,thegapbetweenthearmscanalsoberegulatedby
adjustingthefasteningscrewsofthelowerarmholdercasting(seetechnicaldata).
- Openthesafetygatelocatedontherearofthespot-welderbylooseningthefour
fasteningscrewstogetattheelectrodeforceadjustmentnut(wrenchNo.30).
 Compressingthespring(screwthenutclockwise)willcausetheelectrodestoexert
graduallyincreasingforce withvaluesbetweenthe minimum andthemaximum
(see technical data).
 Suchforcewillincreaseinproportiontotheincreaseinthethicknessofthesheets
to be welded and to the diameter of the electrode tip.
- Also regulate the ow reducer in FIG. D3-2 to decelerate the descent of the
electrodes;
 Itisrecommendedtocompensatethedecelerationofthearmclosurewithalonger
approachtimetoallowtheforcetoreachthemaximumlevelbeforethemachine
starts welding.
 Indicatively, withan inletpressure of8 barand theregulator screwunscrewed
halfway,set100approachcycles(2s);withtheregulatorscrewfullyopen(screw
completelyturnedinacounterclockwisedirectionandtheairownotchoked)set
20cycles(400ms).
- Closethegatetopreventextraneousmatterfromenteringandtopreventaccidental
contact with live or moving parts.
- CheckthecompressedairconnectioninPCPmodels,connectthefeedpipetothe
pneumaticsystem,adjustthepressurebyturningthereducerknobuntilthegauge
reads6bar(90PSI).
6.2 ADJUSTING THE PARAMETERS
The parameters determining the diameter (section) and the mechanical resistance of
spot welding are:
- forceexertedbytheelectrodes(daN);1daN=1.02Kg.
- diameteroftheelectrodecontactsurface(mm);
- weldingcurrent(kA);
- weldingtime(cycles):at50Hz1cycle=0.02sec.
Insummary,alltheabovefactorsmustbetakenintoconsiderationinadjustingthe
spot-weldergiventhattheyinteractbetweeneachotherwithrelativelyamplemargins.
Furthermore, other factors that could modify the results should not be neglected.
These are:
- excessivevoltagedropsonthepowerline;
- spot-welderoverheatingduetoinsufcientcoolingornon-observanceoftheduty