MIG - measure Volts, Amps, wire-feed-speed

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Hello all

Getting into MIG welding.  However, my notebook full of arbitrary
settings for different machines like "2-4,8","1-3,2~1/3", "6A,7" and
so on (in my own notation, this is
"(<voltage-tap-setting>,<wire-feed-speed-dial-postion>)")

Problem is, if machines are different, is "2-2,7" the same condition
as "6A,7", for instance?

How do you measure Volts and Amps on a MIG welder?  And can you
measure wire feed speed in say metres-per-second or inches-per-minute?

Richard Smith

Re: MIG - measure Volts, Amps, wire-feed-speed
Hi Richard
Check Millers website, they have a mig handbook that will answer all your
questions.  I just bought it and am very impressed with the information.
The book is $25.00 and worth it.  See Ya
Travis
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Re: MIG - measure Volts, Amps, wire-feed-speed
Any regular electronic voltmeter can be set on volts scale and connected
between the power lead and ground lead.  You could do it at the power supply
or at the feeder and the ground.
    Amperage is pretty hard to measure unless you have a very heavy ammeter
that can take the load.
    To measure feed run the wire out for six seconds, measure and multiply
by ten for your rate per minute.  Sometimes dials are marked with the feed
per minute and on later models it is given via a digital readout on the
feeder.
    One on Miller's articles gives conversion from feed rate to amperage for
different wire diameters.  I will look around again for it.
Randy

Hello all

Getting into MIG welding.  However, my notebook full of arbitrary
settings for different machines like "2-4,8","1-3,2~1/3", "6A,7" and
so on (in my own notation, this is
"(<voltage-tap-setting>,<wire-feed-speed-dial-postion>)")

Problem is, if machines are different, is "2-2,7" the same condition
as "6A,7", for instance?

How do you measure Volts and Amps on a MIG welder?  And can you
measure wire feed speed in say metres-per-second or inches-per-minute?

Richard Smith



Re: MIG - measure Volts, Amps, wire-feed-speed

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Thanks Randy

Simple but 100% effective.  Will work for every machine I now
encounter.

Overlooked this - that no machine I now meet and most participants on
the group meet has a "soft-start" - so can do this.  Bend the wire
over at the tip by 90deg, pull the trigger for 6seconds and measure
from the contactor to the bend.

Randy - reason I overlooked this - when doing my welding research in
the 90's most of the machines I met were "top of the range" - very
expensive machines - with "soft start".  So that technique wouldn't
work.

Explanation - with "soft start" the wire feeds slowly until an current
is drawn (the arc starts) whereupon the wire-feed gets going at its
set value.  Makes starting your weld easier.  So when you pull the
trigger with the torch pointing up in the air, the wire feed you see
is much slower than the feed rate when welding.

Guess "reactive filter" helmets, where you can see what you are doing
as you line up the torch, make the soft-start less important these
days(?).

I'll go looking up the wire-feed-speed to amps chart - many thanks.

Richard S.

Re: MIG - measure Volts, Amps, wire-feed-speed
http://www.millerwelds.com/pdf/mig_handbook.pdf
    Try page four for some amperage guidelines.
Randy


Hello all

Getting into MIG welding.  However, my notebook full of arbitrary
settings for different machines like "2-4,8","1-3,2~1/3", "6A,7" and
so on (in my own notation, this is
"(<voltage-tap-setting>,<wire-feed-speed-dial-postion>)")

Problem is, if machines are different, is "2-2,7" the same condition
as "6A,7", for instance?

How do you measure Volts and Amps on a MIG welder?  And can you
measure wire feed speed in say metres-per-second or inches-per-minute?

Richard Smith



Re: MIG - measure Volts, Amps, wire-feed-speed

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Randy, everyone

This - the Miller manual you mention - was really interesting for me.
It suggests what might be called a "current-lead" method to find your
settings on the MIG welding machine -- works because:

* for MIG welding you want the 1Amp-per-0.001inch of thickness used
  for eg. TIG welding

* you can estimate current from wire-feed-speed given the wire
  diameter.

* you can measure wire-feed-speed easily

I've been shown a voltage-lead method which is much more trial-and-error.

Appended is Miller's current-lead method, as best I can transcribe it into
text without their diagrams:

Richard Smith

--------------------------------

from
http://www.millerwelds.com/pdf/mig_handbook.pdf
- illustrated explanation on pg4

Setting up a MIG machine - current-lead method


   Taking example of 1/8th-inch=0.125in (3mm) plate


<Stage 1>
Current<->thickness rule -- 1Amp per 0.001inch of thickness (40A per mm)

   So looking for 125A

<Stage 2>
Consider/survey/select wire size (diameter) options given their
current range.
Wire-size       |       Amp-range
0.8mm (0.030in) |       40-145A
0.9mm (0.035in) |       50-180A
1.2mm (0.045in) |       75-250A

   Each of these three wires accommodates the 125A needed

<Stage 3>
Deduce from known wire feed speed <-> current relationship the wire
feed speed needed, then set it with MIG machine's wire feed speed
adjuster

The w.f.s. <-> current relationships

Wire-size       |       Recommendation
0.8mm (0.030in) |       2 inches-per-minute per Amp
0.9mm (0.035in) |       1.6    -"-
1.2mm (0.045in) |       1      -"-

   So for our 3mm (1/8th-inch) weld, would be
   Wire-size            |   calculation   |   w.f.s.
   0.8mm (0.030in)      |   2 * 125       |   250ipm
   0.9mm (0.035in)      |   1.6 * 125     |   200ipm
   1.2mm (0.045in)      |   1 * 125       |   125ipm
  
<Stage 4>
Select voltage

Low voltage      ->   wire "stubbing"
Correct voltage  ->   smooth running (the "rasping" sound)
High voltage     ->   arc unstable, spatter

Re: MIG - measure Volts, Amps, wire-feed-speed
    Something that many people don't realise is that amperage on wire feed
constant voltage machines can vary widely.  Increasing or decreasing
stickout can change amperage down or up 25 amps from the ideal stickout.
    When one gets up into the higher amperages this can make a significant
difference in the weld bead.
    The amperage is only an approximation.  Each operator will be using the
same settings and yet be running a different amperage depending on stickout
used.
    Most weld procedures written up for critical welding will include the
stickout to be used by the operator.
Randy


Randy, everyone

This - the Miller manual you mention - was really interesting for me.
It suggests what might be called a "current-lead" method to find your
settings on the MIG welding machine -- works because:

* for MIG welding you want the 1Amp-per-0.001inch of thickness used
  for eg. TIG welding

* you can estimate current from wire-feed-speed given the wire
  diameter.

* you can measure wire-feed-speed easily

I've been shown a voltage-lead method which is much more trial-and-error.

Appended is Miller's current-lead method, as best I can transcribe it into
text without their diagrams:

Richard Smith





Re: MIG - measure Volts, Amps, wire-feed-speed
Something like this
http://support.metermantesttools.com/meterman-sales/download/asset/1646618_b_6118_eng_w.pdf
would be pretty groovey for that.

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Re: MIG - measure Volts, Amps, wire-feed-speed
That looks like it works on both sides of the pond - 50 and 60 Hz and then some.
So it must be Hall effect - and a quality IC inside.

Have no idea on price - but it is qualified by many countries around the world
by the special seals.

I have a low cost one like this - and a 1000 amp HP version that plugs in.

I like the peak hold - as I'm not normally fast enough or even around when peak
comes.
RMS is good for the longer versions of the voltage - not surges at current
starts and such.

Martin
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder


JensenC wrote:
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http://support.metermantesttools.com/meterman-sales/download/asset/1646618_b_6118_eng_w.pdf
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Re: MIG - measure Volts, Amps, wire-feed-speed
In article

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A standard voltmeter can read the volts while welding.
To measure the amps you need a DC amprobe clamp.
I have one that plugs into my Fluke meter.

Most amprobe clamps are for AC only.

--
"I love deadlines, especially the wooshing sound they make as
they fly by"  - Douglas Adams

Re: MIG - measure Volts, Amps, wire-feed-speed
I'd like to add the best spot is likely on the Gnd return - as other conductors
are not present running switch currents and noise.

The Ac/Dc Amprobes use a hall effect device that measures the current to an
amplifier
and then to the electronics.  AC is more turns ratio and rectified for the
electronics.

Martin
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder



Ernie Leimkuhler wrote:
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