Inductor value for a mig welder
tuc...@conninc.com
splatters something terrible
so i opened the case to find only a transformer and a few diodes, I
hope to add a inductor
to help stabilize the arc. The welder is 70-90 amp output, I have a
high current air core choke
thats heavy enough but i need to add a core of some type to raise the
inductance. It has a
2" round I.D. I need a sugguestion of a type of core to add to it &
maybe a value in mh ?
Grant Erwin
You are REALLY wrong about what's happening. It isn't the transformer or the arc
characteristic that's giving you crummy-looking welds, it's the fluxcore wire,
which is the nature of the beast. Live with it until you can afford a real MIG
welder which will let you run a gas shield, then you can easily run gorg-ass
beads all day long.
And by the way when you go to sell your HF "MIG" welder, *please* don't ask more
than $45 or so, that's all they go for used. They are essentially throwaway
units. Think of it like you paid $139 (or whatever) for a lesson in how to not
buy a welder, and you got a $45 welder thrown in with the deal.
GWE
tuc...@conninc.com
> I wonder why they call it MIG. MIG stands for Metal Inert Gas. But
> there is no gas capability in that "MIG".
Good question, ive noticed the cheap migs that also have gas hookup
are called Dual Mig
mine just says mig & should say AC flux wire welder, without a
inductor it acts like AC
anyway.
Grant Erwin
> there is no gas capability in that "MIG".
>
>
You're right, Igor, but MIG has long since lost its narrow meaning, and now is
often generalized to mean anything that includes a wirefeed. If you want narrow
meanings then use FCAW (like the HF machine) or SMAW (what you think of as MIG).
GWE
Andy Dingley
<ignoram...@NOSPAM.29795.invalid> wrote:
>I wonder why they call it MIG.
Depending on who "they" are, they don't. It's MAGS unless you're using
argon, and only in that case is it MIG.
billh
helps put the inductor into the ouput lead. I assume it will handle the
current. Try the welder and see if it is any better. If you want more
inductance, try putting a mild steel core into the center of the coil and
see it that helps any. If you want more try making a loop of mild steel,
however, you will have to leave an air gap or the core will staturate
rendering it useless. As for value, don't know, all you have to do is shift
the voltage/current phase a few degrees such that the arc and voltage don't
go to zero together. If you have long secondary leads there supposedly is
enough inductance in them to do the job.
You can add the inductor outside the box so it will be easy to fool with. If
it really helps then you can worry about putting it inside.
billh
<tuc...@conninc.com> wrote in message
news:1136303808....@o13g2000cwo.googlegroups.com...
Brent Philion
No caps either and no choke?
Robert Ball
generic than MIG or MAG.
Robert Ball
your choke run hot so you may need to put a fan on it too.
Grant Erwin
capacirors, NOT a big inductor. A big inductor makes a CC welder ..
GWE
Robert Ball
voltage (CV) vs constant current (CC).
tuc...@conninc.com
> thats ALL thats in there?
>
> No caps either and no choke?
Yep thats all, its a ( Chicigo Easy Mig 100 ) sold by harbor freight
and assembled in
Italy. It does have two small caps & a resistor feeding the
unregulated wire feed motor.
Brent Philion
smooth that out just keep hooking them in parralell
as for those who pointed out that a choke is for CC and caps are for CV
essentially half waves leave you welding with AC and even a kick in the
nuts would work better than that
BTW instead of getting a Big massive iron cored toroidal inductor the
caps are way lighter.
I would however like to say that i agree with whoever said this was an
example of what not to buy in a welder. its not a product of appropriate
quality and the caps probably saved them 1 or 2 dollars in expense to
witre it up
billh
"Brent Philion" <bre...@sympatico.ca> wrote in message
news:abRuf.32173$X25.6...@news20.bellglobal.com...
Don't want to get into a semantics argument but welding with half-waves is
not welding with AC. The current/voltage may go to zero which isn't ideal
but the opposite polarity does not exist. A half or full-wave rectified
waveform with the peaks in the positive direction has a positive DC
component to it. If it is reversed, then it has a negative component, but
not AC.
billh
billh
billh
"Robert Ball" <rwba...@comcast.net> wrote in message
news:tOidnQisO69...@comcast.com...
dca...@krl.org
have is on A size paper and the original must have been something like
a D size. I am pretty sure it is a Hobart drawing. For what it is
worth, it shows a capacitor, 50,000 mfd 30 volts and an inductor L1
which is just described as " reactor filter ". So I am no help on the
size, but can say that there is an inductor.
Dan
Brent Philion
>>>
>>
>>several large electrolytic caps rates at at least 200v should help smooth
>>that out just keep hooking them in parralell
>>
>>as for those who pointed out that a choke is for CC and caps are for CV
>>essentially half waves leave you welding with AC and even a kick in the
>>nuts would work better than that
>>
>>BTW instead of getting a Big massive iron cored toroidal inductor the caps
>>are way lighter.
>>
>>
>>I would however like to say that i agree with whoever said this was an
>>example of what not to buy in a welder. its not a product of appropriate
>>quality and the caps probably saved them 1 or 2 dollars in expense to
>>witre it up
>
>
> Don't want to get into a semantics argument but welding with half-waves is
> not welding with AC. The current/voltage may go to zero which isn't ideal
> but the opposite polarity does not exist. A half or full-wave rectified
> waveform with the peaks in the positive direction has a positive DC
> component to it. If it is reversed, then it has a negative component, but
> not AC.
> billh
>
>
Point taken it is still DC but it is not the Constand Voltage power
supply that the mig family (GMAW and FCAW) are supposed to use.
You agree with the overall message though?
billh
Yes, I agree and am somewhat amazed that a box with so little in it
functions as a CV supply at all. I don't really know all that much about MIG
but I was under the impression that the wire feed rate determined the
voltage across the arc. It is hard to see how this could be reasonable well
maintained with a supply that is so crude although the rather rapid 60hz (or
is it 120hz) pulses from the supply probably wouldn't be seen given the
relatively slow burning of the wire. The box is operating on the unregulated
average dc voltage. Capacitors certainly would be a good place to start and
I imagine they are quite large in value. Whether or not they have a large
beneficial effect might be questionable given the crudeness of the rest of
the system.
billh
Brent Philion
machine for the same setings angle and travel speed
I bet the bead produced wouldnt be considered acceptable to many
billh
<dca...@krl.org> wrote in message
news:1136389031.8...@g44g2000cwa.googlegroups.com...
the DC since it resists change in current. It doesn't matter that MIG
welding uses a CV source for the inductor to be there (an inductor by itself
will not make a CC source). You can look at it the following way, if the
voltage is high, more current flows in the load and the inductor and builds
a large field, when the output voltage drops because it is having trouble
supplying the needed current, the current drops, the inductor's field
collapses thus supplying more current to let the voltage rise. In other
words, it helps regulate the voltage.
billh
Grant Erwin
> It is a so-called LC filter (inductor capacitor). The inductor helps smooth
> the DC since it resists change in current. It doesn't matter that MIG
> welding uses a CV source for the inductor to be there (an inductor by itself
> will not make a CC source). You can look at it the following way, if the
> voltage is high, more current flows in the load and the inductor and builds
> a large field, when the output voltage drops because it is having trouble
> supplying the needed current, the current drops, the inductor's field
> collapses thus supplying more current to let the voltage rise. In other
> words, it helps regulate the voltage.
> billh
Well, it's more like this: on a stick welder, the resistance of the arc varies
with the arc length. Since it's desirable to put the same amount of heat into
the pool for each inch of weld, it's desirable to flow a constant current
despite the change in load resistance. Thus the attempt to make the DC source
look inductive - an inductor strongly resists changes in current.
GWE
Geoff M
My big old New Zealand made (in 1975)EMF Lynxpak 200A MIG has an inductor.
It is on a variable slide, so you can dial in the amount of inductance to
adjust the arc characteristics.
I don't know the value of it, but it is around 100mm diameter and 350mm
long.
Geoff
billh
"Grant Erwin" <gr...@NOSPAMkirkland.net> wrote in message
news:11robul...@corp.supernews.com...
True enough but the constant current is really achieved through the shunts
in the transformer. Lots of stick welders don't even have an inductor.
billh
ATP*
"Grant Erwin" <gr...@NOSPAMkirkland.net> wrote in message
news:11robul...@corp.supernews.com...
>
which is desirable in short circuit mode- Google induction short circuit
welding- my MIG welder at work has a 4 position inductance control
Martin H. Eastburn
arc to start stuff a bit easier, or keep it going.
The inductor and cap do nothing during pure dc steady state - the current stabilizes
in the coil and the voltage across the cap remains the same. Steady state (unknown in welding):-)
The step response and when arcing on a plate to start current is where the LC comes into
play - The two reactive elements produce sharp (more or less) edges - spikes that jump
through oil or film and clothing... and starts the current flowing due to ionization.
Once flowing, the coil has constant current and idles to standby. The cap is
trying to hold the output voltage the same - just like a steady hand. But once
welding - the cap is swamped - lower impedance in the arc than across the cap.
So it seems that they only work when one strikes an arc or re-strikes or runs
into some scale or something that alters the current.
Agree with an long time friend - GWE
Martin
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH & Endowment Member
NRA Second Amendment Task Force Charter Founder
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John Crighton
<geo...@bigfoot.com.Delete.this.bit> wrote:
>My big old New Zealand made (in 1975)EMF Lynxpak 200A MIG has an inductor.
>It is on a variable slide, so you can dial in the amount of inductance to
>adjust the arc characteristics.
>I don't know the value of it, but it is around 100mm diameter and 350mm
>long.
>Geoff
Hello Geoff,
A picture would be great but too much to ask of you,
but, so that I can form a mental picture:
How many turns of wire?
Is it a single layer of wire?
How far in and out does the variable slide travel?
I imagine all the way in and perhaps half out.
What is the slide made of?
I am imagining laminations in a squarish block
350 mm long. Is that right?
How is the block held mechanically?
How do you adjust the inductor setting in actual
practice?
Do you find there a sweet spot in the inductor setting
for a particular thickness of metal being welded or just
a vague feeling that the setting is correct?
Sorry for so many questions, just interested.
Regards,
John Crighton
Sydney
tony stramella
tuc...@conninc.com
went out before i really tried using it. I was trying to salvage it
for
something? i thought of using it for a low power arc welder but the
open circut voltage is only 30VDC & from what ive read rods require
twice that to start a arc, I have determined the inductor didnt help,
the problem was the wire feed motors voltage comes off the welders
output & varies as the unit welds, so now ive got to build a regulated
/ adjustable wire feed voltage supply and try again.
I thought the price was to cheap to be true but found out it wasent
cheap at all.
R. Duncan
finely tuned way. Inductance is part of this fine tuning.
Some wire feed welders have a slope control which changes inductance.
The slope control adjusts current flowing when elctrode is shorted to
work. Increasing inductance in series with work increases slope
retarding rapid arc current changes and limiting maximum short circuit
current, reducing spatter. More slope is needed for short circuit
transfer and little slope is used for other transfer modes. Most
modern MIG welders don't have slope adjustment.
In short circuit transfer the wire shorts to work 20 to 200+ times a
second.
Short Circuit period:
Wire shorting to work causes amps to increase rapidly. Voltage drops
from arc voltage to much lower level aswire shorts to work and arc
goes out. Amp current increase as volts rise as CV power supply trys
to maintain voltage . Wire continues to feed into puddle forming a
cone until molten wire feeding into puddle is pinched off and arc
reignites.
Arc Period:
Amps begins to fall off while voltage rises sharply. Arc heats wire
and puddle causing cone to flatten into weld puddle and ball of
molten metal to form on end of wire. Wire is feeding while ball forms
and brings ball into contact with puddle causing electrical short
circuit starting another cycle.
If molten metal ball 2 to 4 times wire size drops from wire end before
wire shorts to work it is Globular transfer.
If large moten metal ball 2 to 4 times wire diameter shorts to work it
will explode causing lots of spatter.
Volt and amp meters don't show these quick volt/amp changes only
indicate average voltage or amperage.
Kenneth E. Ghost
Easy to add argon to the HF 90 amp. I am in the process as I speak. Fun too,
learning a lot. Added a bridge R , 160,000 mf cap total, torrid coil, single
20 amp outlet in front panel/power on indicator , heavy power cord and very
heavy work clamp. works like a dream and, its 120 v 20 amp rated, I can take
it anywhere. Gas hookup will be done this week.
--
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TimofGlazz
Easy there buddy, hold your fingers back from that key board and open up a new
tab to do some research before you make yourself look like a gorg-ass. And if
you make gorg-ass beads all day yourself. Well then good for you, you know how
to flip a switch and close a circuit and not kill yourself doing it. I bet
those welding fumes don't take any crud from you because you're tougher then
them.
--
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