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Science Forum Index » Engineering - Joining (Welding) Forum » Problems with 3.2 mm rods
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| Author |
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| Julian |
 Posted: Sat Jan 13, 2007 3:47 pm |
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Guest
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Hello all, I'm new to this newsgroup so I apologise if this problem has been
answered many times before!
My stick welder is a cheap (Clarke) air cooled single phase 175 amp machine.
It's years old and has given good service.
Normally it worked well with 3.2 rods on the thicker stuff, but at my new
home it won't handle them and I have to use 2.5 rods maximum. I've been
making steel workshop doors, and it's now getting on my tits putting in new
2.5 rods like they're going out of fashion and having to make multiple runs
to build the fillet up.
I suspect either a voltage problem or the welder is past its best, I took
some voltage readings with my AVO and here are the results of my test:
51volts open circuit and 22(ish) volts with an arc struck from a 3.2 rod.
Mains, 250volts and 227volts with an arc.
Are these good figures or bad ones, I've no real idea! Any advise gratefully
received.
Thanks Julian. |
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| Julian |
| Posted: Sat Jan 13, 2007 5:25 pm |
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Guest
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"RoyJ" <spamless@microsoft.net> wrote in message
news:FEbqh.10606$w91.8003@newsread1.news.pas.earthlink.net...
Quote: On the this (the other) side of the pond, we don't have the Clarke units
so I'll have to guess that the Clarke is an old transformer welder (buzz
box)
Sorry, I didn't realise this was a US group, but I suppose welding isn't
much different! Yes the Clark welder is just a heavy transformer, with
copper windings, and has a thing that screws in and out of the core
laminates to vary the ouput.
A 175 amp welder should have NO troubles running 1/8" (3.2mm) at
Quote: around 120 amps. Transformer welders are not noted for giving any problems
other than bad contacts or connections. They either work or not work at
all.
I agree, it even has a marking for 4mm rods, though I've never tried them.
Here in the UK we have normally have fused plugs that have a 13 amp fuse
maximum, most people replace it with a 3/8th bolt for welders because they
always blow when the welder is working hard!
Quote:
The fact that it used to work fine, you are running on new power and it
doesn't work well says something. A full 10% voltage drop at a medium load
says some more. Running 120 amps on the stick should mean about 12 to 15
amps on the input side (after the arc is struck) Power factor will skew
things but this is not a very big load. Do the light dim when you weld?
Neighbors complain? What size and length of wire are you running to the
welder?
The welder has a short length of 2.5mm flex, then it has about 30' of 5mm
conductor to the workshop distribution board, then about 25 yards of 6mm
underground to the propery main supply. Then it's the electricity supply
company cable to a transformer on a pole that we share with just one
neihbour. I'm going to check the voltages at the supply tomorrow to see if
the voltage drop is in my cable or theirs. I think we do have voltage issues
because the lights do dim when I start my 9'' angle grinder.
Quote:
You might also have a loose/corroded/loose crimp/connection inside the
welder. Run a few rods, **UNPLUG** the welder, feel each of the
connections inside the welder for one that is extra hot. If it is bad, it
will be very hot.
Actually, that may well be the problem too, I'll do what you say and tell
you if I find anything. One thing I have noted is that the welding arc will
just quit half way through a run for no reason at all, a quick dab in the
pool and the arc strikes back up again - that maybe points to a bad contact
Thanks Julian. |
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| RoyJ |
| Posted: Sat Jan 13, 2007 6:46 pm |
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Guest
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This is not just a US group, people chime in from the UK, OZ, etc. The
US folks are at a disadvantage when you start talking about mains power,
the distribution systems are radically different. But the welding is
pretty much the same. A couple of the UK regulars will probably chime in
later.
Still sounds like a voltage drop someewhere, internal or external. I'll
translate the cable sizes later to see what voltage drop you should be
getting. Take some readings, pop up any other symptoms, someone should
have some ideas.
Julian wrote:
Quote: "RoyJ" <spamless@microsoft.net> wrote in message
news:FEbqh.10606$w91.8003@newsread1.news.pas.earthlink.net...
On the this (the other) side of the pond, we don't have the Clarke units
so I'll have to guess that the Clarke is an old transformer welder (buzz
box)
Sorry, I didn't realise this was a US group, but I suppose welding isn't
much different! Yes the Clark welder is just a heavy transformer, with
copper windings, and has a thing that screws in and out of the core
laminates to vary the ouput.
A 175 amp welder should have NO troubles running 1/8" (3.2mm) at
around 120 amps. Transformer welders are not noted for giving any problems
other than bad contacts or connections. They either work or not work at
all.
I agree, it even has a marking for 4mm rods, though I've never tried them.
Here in the UK we have normally have fused plugs that have a 13 amp fuse
maximum, most people replace it with a 3/8th bolt for welders because they
always blow when the welder is working hard!
The fact that it used to work fine, you are running on new power and it
doesn't work well says something. A full 10% voltage drop at a medium load
says some more. Running 120 amps on the stick should mean about 12 to 15
amps on the input side (after the arc is struck) Power factor will skew
things but this is not a very big load. Do the light dim when you weld?
Neighbors complain? What size and length of wire are you running to the
welder?
The welder has a short length of 2.5mm flex, then it has about 30' of 5mm
conductor to the workshop distribution board, then about 25 yards of 6mm
underground to the propery main supply. Then it's the electricity supply
company cable to a transformer on a pole that we share with just one
neihbour. I'm going to check the voltages at the supply tomorrow to see if
the voltage drop is in my cable or theirs. I think we do have voltage issues
because the lights do dim when I start my 9'' angle grinder.
You might also have a loose/corroded/loose crimp/connection inside the
welder. Run a few rods, **UNPLUG** the welder, feel each of the
connections inside the welder for one that is extra hot. If it is bad, it
will be very hot.
Actually, that may well be the problem too, I'll do what you say and tell
you if I find anything. One thing I have noted is that the welding arc will
just quit half way through a run for no reason at all, a quick dab in the
pool and the arc strikes back up again - that maybe points to a bad contact
Thanks Julian.
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| Richard Smith |
| Posted: Sat Jan 13, 2007 7:22 pm |
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Guest
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RoyJ <spamless@microsoft.net> writes:
Quote: This is not just a US group, people chime in from the UK, OZ, etc.
The US folks are at a disadvantage when you start talking about mains
power, the distribution systems are radically different. But the
welding is pretty much the same. A couple of the UK regulars will
probably chime in later.
Still sounds like a voltage drop someewhere, internal or
external. I'll translate the cable sizes later to see what voltage
drop you should be getting. Take some readings, pop up any other
symptoms, someone should have some ideas.
Julian wrote:
"RoyJ" <spamless@microsoft.net> wrote in message
news:FEbqh.10606$w91.8003@newsread1.news.pas.earthlink.net...
On the this (the other) side of the pond, we don't have the Clarke
units so I'll have to guess that the Clarke is an old transformer
welder (buzz box)
Sorry, I didn't realise this was a US group, but I suppose welding
isn't much different! Yes the Clark welder is just a heavy
transformer, with copper windings, and has a thing that screws in
and out of the core laminates to vary the ouput.
A 175 amp welder should have NO troubles running 1/8" (3.2mm) at
around 120 amps. Transformer welders are not noted for giving any
problems other than bad contacts or connections. They either work
or not work at all.
I agree, it even has a marking for 4mm rods, though I've never tried
them. Here in the UK we have normally have fused plugs that have a
13 amp fuse maximum, most people replace it with a 3/8th bolt for
welders because they always blow when the welder is working hard!
The fact that it used to work fine, you are running on new power
and it doesn't work well says something. A full 10% voltage drop at
a medium load says some more. Running 120 amps on the stick should
mean about 12 to 15 amps on the input side (after the arc is
struck) Power factor will skew things but this is not a very big
load. Do the light dim when you weld? Neighbors complain? What
size and length of wire are you running to the welder?
The welder has a short length of 2.5mm flex, then it has about 30'
of 5mm conductor to the workshop distribution board, then about 25
yards of 6mm underground to the propery main supply. Then it's the
electricity supply company cable to a transformer on a pole that we
share with just one neihbour. I'm going to check the voltages at the
supply tomorrow to see if the voltage drop is in my cable or
theirs. I think we do have voltage issues because the lights do dim
when I start my 9'' angle grinder.
You might also have a loose/corroded/loose crimp/connection inside
the welder. Run a few rods, **UNPLUG** the welder, feel each of the
connections inside the welder for one that is extra hot. If it is
bad, it will be very hot.
Actually, that may well be the problem too, I'll do what you say and
tell you if I find anything. One thing I have noted is that the
welding arc will just quit half way through a run for no reason at
all, a quick dab in the pool and the arc strikes back up again -
that maybe points to a bad contact
Thanks Julian.
I can contribute a really low-intellect diagnostic...(!)
Take the welder and plug it in at another property. A UK ring main
should be good to 26A (? 2x13A when no other draw on ring). Or plug
the welder into the socket by on the cooker's wiring point. In the UK
that is always a 30A spur (direct from the fuse board with no other
load on it). Either of those should indicate whether it is supply,
before starting to take the welder itself apart looking for probs.
To the American respondee - this machine is indeed a "buzz box". As I
know them, they have a desperately low duty cycle but they have a
"sweet spot" at around 120A (3.2mm (1/8th inch) electrode) - giving an
intense arc for making trailers and the like.
Richard Smith |
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| Julian |
| Posted: Sun Jan 14, 2007 6:23 am |
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Guest
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"RoyJ" <spamless@microsoft.net> wrote in message
news:gjdqh.10622$w91.8840@newsread1.news.pas.earthlink.net...
Quote: This is not just a US group, people chime in from the UK, OZ, etc. The US
folks are at a disadvantage when you start talking about mains power, the
distribution systems are radically different. But the welding is pretty
much the same. A couple of the UK regulars will probably chime in later.
Still sounds like a voltage drop someewhere, internal or external. I'll
translate the cable sizes later to see what voltage drop you should be
getting. Take some readings, pop up any other symptoms, someone should
have some ideas.
OK, I've mostly solved the problem. I ran through 2 3.2 rods without a rest
and felt all the components, both primary and secondary windings were just
too warm to touch constantly, everything else was cool except for the little
rotary switch on the mains input, one contact burned my finger.
I've put the switch in the rubbish bin and joined the wires with a
'chocolate block' connector - now I have to switch it off at the wall, which
is no bother.
It now welds fine with 3.2 rods, not quite as well as at my old house, but
OK.
I did a trial and ran 6.5 Kw's worth of electric fan heaters from the
workshop (welder) circuit. I've only got about a 5 volts drop between the
workshop and the mains incomer, most of the voltage drop (20+ volts) is
upstream of the incomer. In the UK we have 230volts -6% + 10% which equates
to 216 to 253 volts. I don't think I can force my electricity supplier to
upgrade my supply based on those figures.
Changing the subject a little now, a few months ago I borrowed my mate's
inverter stick welder - it's light and I needed to weld a joist high up on a
steel frame building, I have to say that the weld seemed to progress much
more smoothly than with the old style welders. I'm wondering about the pros
and cons of these 'electronic' stick welders and if I should purchase one. I
wonder if they cope with a relatively poor supply voltage well?
Cheers Julian. |
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| RoyJ |
| Posted: Sun Jan 14, 2007 12:15 pm |
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Guest
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It kinda nice to actually make some progress diagnosing problems!
I'm not at all suprised to hear about the contactor being bad. I'll bet
it was HOT! I would suggest putting in a new switch, if just for
safety reasons. Sounds like an upgraded switch would be a good thing.
Someone mentioned Clarke being the cheap units with horrible duty cycle,
coils too hot to hold your hand on them says 130F - 140F (60C). Too hot
for long life of insulation.
Most of us see voltage drops on our shop systems. I'm lucky, the 50 kva
transformer is about 150' of wire from my main panel which is located on
the shop wall.
The inverter welders are really nice: lightweight and very portable. The
inverter technology gives a much better power factor, allows one to use
considerably smaller input circuits than required for the inductive
loads in transformer unit. But beware: the cheap units have non existant
duty cycles.
Ease of use and smoothness of the weld have a lot of factors: a high
open circuit voltage (OCV) makes it easier to start or restart the rod.
DC will give a smoother weld. Larger capacity usually means better
current regulation in the normal ranges. Higher duty cycle is always
nice (stick welding on a project should have around a 60% duty cycle in
the current range you are working with)
Julian wrote:
Quote: "RoyJ" <spamless@microsoft.net> wrote in message
news:gjdqh.10622$w91.8840@newsread1.news.pas.earthlink.net...
This is not just a US group, people chime in from the UK, OZ, etc. The US
folks are at a disadvantage when you start talking about mains power, the
distribution systems are radically different. But the welding is pretty
much the same. A couple of the UK regulars will probably chime in later.
Still sounds like a voltage drop someewhere, internal or external. I'll
translate the cable sizes later to see what voltage drop you should be
getting. Take some readings, pop up any other symptoms, someone should
have some ideas.
OK, I've mostly solved the problem. I ran through 2 3.2 rods without a rest
and felt all the components, both primary and secondary windings were just
too warm to touch constantly, everything else was cool except for the little
rotary switch on the mains input, one contact burned my finger.
I've put the switch in the rubbish bin and joined the wires with a
'chocolate block' connector - now I have to switch it off at the wall, which
is no bother.
It now welds fine with 3.2 rods, not quite as well as at my old house, but
OK.
I did a trial and ran 6.5 Kw's worth of electric fan heaters from the
workshop (welder) circuit. I've only got about a 5 volts drop between the
workshop and the mains incomer, most of the voltage drop (20+ volts) is
upstream of the incomer. In the UK we have 230volts -6% + 10% which equates
to 216 to 253 volts. I don't think I can force my electricity supplier to
upgrade my supply based on those figures.
Changing the subject a little now, a few months ago I borrowed my mate's
inverter stick welder - it's light and I needed to weld a joist high up on a
steel frame building, I have to say that the weld seemed to progress much
more smoothly than with the old style welders. I'm wondering about the pros
and cons of these 'electronic' stick welders and if I should purchase one. I
wonder if they cope with a relatively poor supply voltage well?
Cheers Julian.
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