Weak Arc on Lincoln 225 ac

[the old grind]

IT, we're just thinking that when one leg is positive the other is negative AKA 180^ apart, no? The average across both hots (240v) is still RMS and still 60 Hz, and I don't see both legs being in the same phase if the x-former on my pole is fed by one wire and is obviously 1 Ph. Warm up that o'scope and show us a trace or two lest we remain confused.

btw, I have sound & light meters, refractometer, thermal cams/scopes, inline and clamp-on ammeters, etc but still lack a scope. If yours is idle, is it for sale?

 

[Fuddy1952]

Now "I can take a scope and make it look like anything I want for starters." makes absolutely no sense whatsoever, just like putting four 6 volt batteries in series equals 48 volts.
At this point, the conversation to understand one has to eliminate ego, hurt feelings, "I'm smarter than you"...the list goes on.
An oscilloscope beam scans across, with adjustments for sweep time (x) and amplitude .
Industrial's battery analogy is good (forget voltage is wrong) because if you series four 6 volt batteries all + to --, then from one end to the other you have 24 volts. From center (2 batteries either side) you have 12 volts.
So now residential current. The neutral (ground) is analogous to this center batteries connection.
Incoming you have the neutral (ground) which is the power transformer center tap. The other two transformer leads you have 240 volts across, half that or 120 volts from neutral to either lead.
Oscilloscope probe takes two wires. Wire on neutral then either transformer outer lead you see the 120v(rms) sine wave. From outer leads you see 240v(rms) sine wave.
Sine wave peaks at about 170v (120vrms), 340v (240vrms).
Back to batteries example. Oscilloscope leads across all batteries you see the sweep line go up to 24v, reverse leads line goes DC own to 24v. Same with lead batteries center up to 12v one end, down to 12v other end.
A line since voltage is constant (DC).
THIS is so important understanding oscilloscope on AC. Across transformer outer leads the sine wave 240vrms. However! From center neutral to one lead a sine wave...but as THAT sine wave rises, the other lead falls. They ARE NOT in synchronization! Those two 120vrms sine waves are 180 degrees OUT OF PHASE with reference to neutral. Exactly like the battery example. From center one end it's positive 12v with respect to center. Center to OTHER end it's NEGATIVE with respect to center.
Hope I've made it clear. The YouTube guy is correct.

 

[k0ua]

I dont know a lot about electricity but my 3 prong welding plug has 2- 110v that if you check each lead to the ground you get 110 on each leg so I always assumed that both 110v legs went back thru the ground lug to complete the circuit.

The ground lug is NOT involved in powering the welder. The two 120 volt legs are on different phases. Therefor 240 volts are developed between the legs. The welder uses this 220 volts for its power. No neutral, and the ground is a safety ground, and no current flows on this ground wire.

 

[Fuddy1952]

The ground lug is NOT involved in powering the welder. The two 120 volt legs are on different phases. Therefor 240 volts are developed between the legs. The welder uses this 220 volts for its power. No neutral, and the ground is a safety ground, and no current flows on this ground wire.

Thanks. Correct.

 

[Industrial Toys]

I got to thinking about my 10hp rotary phase converter, and how you can use those two legs as phases and then make up your third phase with a capacitor based phase shift circuit. So, I have to confess, I am CONFUSED. :confused3:

If for no reason, that those two legs won't be 120 degrees out of phase???

 

[BukitCase]

The capacitor phase shift part only works (with the two 180* single phase "legs") to get the 3 phase motor running; then the phase shifted leg cuts out (like a single phase starting cap) and the 3 phase motor continues to run on the two single phase (180* apart) legs - but ONLY at about 65% of its normal rated power.

A SERIOUS RPC uses a single phase motor to run an actual 3 phase GENERATOR - more elegant, but kinda limited by the size motor that's available for single phase "household" current; at about 80% efficiency, a 5 horse single phase motor might get you 4 horsepower.

I haven't worked on much 3 phase stuff, so can't really explain how a 3 phase motor is used to get a 3rd phase on THAT type of converter, other than the motor is used to phase shift at least ONE of the two single phase legs (I think)... Steve

(keep in mind that capacitors aren't the ONLY component that can shift phase; so can inductors - like motor windings, for example)

 

[Industrial Toys]

When you say "Generator" do you mean an idler motor or the idler is then connected to another generator still?

 

[BukitCase]

In my previous post I meant just a simple single phase motor directly driving a 3 phase generator; no idler motor involved. For something with an idler motor, I had this bookmarked (at the time, I was considering older 3 phase stuff like a lathe and mill)

diy - How to Build a Rotary Phase Converter to Convert Single Phase to Three Phase

Since you asked about an idler motor, you may already be familiar with that method... Steve

 

[Industrial Toys]

Yes, I have a 10hp home built 600 volt Rotocon. Built it to run a Lincoln Mig Welder, but the computer in that never liked the fake 3 phase. AND I never liked starting a 10hp rotocon everytime I wanted to weld.

 

[BukitCase]

Thought you might :=)

Here's an example of the "simple" 1 to 3 I first mentioned -

1-to-3 Power Source Generates 3-Phase Power from Single-Phase Input

(Obviously NOT a "home owner" cost factor)

From what I've read in the past, it seems like MOST applications for home use would best be served by a SEPARATE VFD for each piece of equipment (VFD's don't seem to appreciate being "passed around", or "home grown" switching methods much) - plus, the soft start option could be handy. My little Grizzly mill is geared, 6 speed and (if I EVER run low on projects) I've considered adding a VFD; both for the "in between" speeds, AND the soft start. Doesn't take a very heavy tool for that surge start to get a bit jarring... Steve

 

[jaxs]

At this point, the conversation to understand one has to eliminate ego, hurt feelings, "I'm smarter than you"...the list goes on.
.

(A) I agree with that observation.
(B) The ONLY reason terms like phase shift,sinewave,waveform,sinusoidal, reactive power (and the list go's on) dragged into a discussion here on TBN,is to find who can pee highest on the wall. It's a kid's game that men with feelings of insecurity play.
(C) I challenge anyone to tell us in layman's terms why our TBN members need to understand terms listed in B above and/points made in preceding posts.
(D) For the benifit of those who are being lead to belive they must know this stuff in order to troubleshoot their tractor,home lighting,home appliances,central heat and air and 99.9% of anything else in the rest of their lives. I ask those who are comfortable troubleshooting electrical on tractors,cars and home,do you understand all this (I certainly do'nt)? Would you encourage diy homeowners and motorests to study theory of AC current?

 

[Industrial Toys]

Interesting post. Someone once said that never have so many known any thing about so much around them, or something similar.

When I was around 14 I had a friend who knew much about elecronics and theory, but never managed to build anything that worked.

I don't just take something told to me for granted, I have to understand it at a gut level. OBVIOUSLY, this I am having trouble with.

I think it's a big mistake to think that one can just understand some complex stuff, with a brief explanation. Maybe ones EGO doesn't like that, but it's true.

 

[Fuddy1952]

To me it boils down to good people trying to help the OP's welder problem. If you start from the beginning people suggested different things that any one or combination could have been the problem. Apparently, by #12 post instead of welder getting 240v it was getting 120v, so weak spark.
Getting technical or in depth isn't wrong, just skip over it.
As far as working on stuff, the more different things you can do can be combined to fix or fabricate things.

 

[WranglerX]

I simply read nomenclature plate on welder or compressor motor or appliance and use a voltmeter to verify that the voltage is correct for application..... And have really basic understanding of how 120 VAC and 240VAC supply circuits are wired.... Has always worked for me.... 38 years in telecommunications and above concepts have never failed me...

But the pissing match is entertaining...

Dale

 

[1 of U]

it's a good thing ,,, this ole boy wasnt running a 3 phase welder ,,,, I
just think of the replies on 3 phase ...

now I understand the phrase :

a Jack of all trades & a Master of none ...

 

[k0ua]

(A) I agree with that observation.
(B) The ONLY reason terms like phase shift,sinewave,waveform,sinusoidal, reactive power (and the list go's on) dragged into a discussion here on TBN,is to find who can pee highest on the wall. It's a kid's game that men with feelings of insecurity play.
(C) I challenge anyone to tell us in layman's terms why our TBN members need to understand terms listed in B above and/points made in preceding posts.
(D) For the benifit of those who are being lead to belive they must know this stuff in order to troubleshoot their tractor,home lighting,home appliances,central heat and air and 99.9% of anything else in the rest of their lives. I ask those who are comfortable troubleshooting electrical on tractors,cars and home,do you understand all this (I certainly do'nt)? Would you encourage diy homeowners and motorests to study theory of AC current?

It is important to understand that the power delivered to your home is in the form of two phases. And that 1/2 of your electrical panel is one phase and the other half is the other phase, and you would profit greatly if you looked at the panel BEFORE any breakers are put into it to see how the phases are interleaved and actually appear on BOTH sides of the breaker slots. So when you put a double sized breaker in for a 240 volt application like your welder, then one wire is on one phase and the other wire is on the other phase.

There is no reason you cannot understand the concept of a phase and what that means by looking at it on an oscilloscope. After all you looked at plenty of sine waves graphed out in 9 th grade algebra didn't you? I sure did. Did you think all of that algebra and geometry crap was just abstract stuff and had no meaning in the real world? Well it did. And if you will recall back to some of the equations you solved back when you were just a pimply faced kid, were actual electronic formulas that you would later recall.

Bet you didn't pay any attention did you?. Bet you were too busy looking up the girls dresses weren't you? Having knowledge and understanding of the practical real world can go a long darn way in repairing your tractor. When I see grown men come on here and don't have the slightest inkling of ohms law or how a breaker box is broken out into the two phases of electrical delivery, it makes my *** hurt to think how poor our education system is. You see it as grown men peeing up a wall, I see it as enrichment of knowledge that they already should have had.

I see men on here every day, that cannot understand the concept of a high resistance joint on a copper cable can cause a voltage on that cable to be different than the voltage on the other end. Yes Mr. Ohm is an old dead white guy, but he set down to paper a law a long time ago that we still have to live with. And you looked at that law in its various forms in 9th grade algebra a lot of times. Of course they didn't tell you what it was, but it was there and how to use it. Shame on them.

So when someone tries to educate your stupid *** and if you don't understand it, please take the time to engage them in a conversation and say "I don't understand that, could you please enlighten me a little more or put it into words I CAN understand" instead of thinking we are trying to "baffle you with bull****" Some of the folks here on TBN are pretty darn smart accomplished guys. Some are a whole lot smarter than I. I have learned many things here over the few years I have been here, and I have helped many guys get their tractor started, or something figured out. Sometimes it takes all of us to get their tractor started or something else figured out, with many of us adding small pieces to the puzzle. That is the beauty of this place. So don't go knocking it when some one tries to enlighten you. You are not only showing your ignorance but you are also showing a disdain for knowledge and learning. And gaining knowledge is something we all should be doing from the day we are born to the day we shall die.

So in the future, when you don't understand some concept, then by all means hold up your hand and say so. Some of us will actually try to help you understand that thing. You may be surprised what you can learn if you try.

 

[the old grind]

Now that's kinda thick and confusing. There aren't two phases across 240v, just the positive and negative swings. Let's call the +/- swings push and pull.

120v sees alternating push and pull, only needs one wire and a ground. We can center-tap two legs that are 180^ apart but on the same one phase.

240v sees one leg push to common while the other pulls from it. Each leg is always opposite the other just like the 120v bars in the panel.

While the 120v legs are pushing/pulling opposite directions looking from the common bar there is only one source phase and tapping the 120s in series give us 240v as one leg pushes and one pulls from common as if the C-T isn't there.

Phase means different things when comparing components to power sources. One 240v sine wave coming tapped as 120v's that are 180^ out of phase with each other, but still from a single phase 240v source. There is no 'second' phase, only two possible relationships either side of common.

Apologies for long explanation and member-bashing.

 

[k0ua]

Your welder has no "common" wire, and the ground can also be disconnected and the welder will work just fine. You just need the two phases where the sine wave is at a peak on the one phase and the sine wave is at a negative peak on the other phase at any instant in time. The reason for the ground wire on your welder is so if the welder "transformer" should short to the case which is grounded, the breaker would trip. If you didn't have the ground wire connected, the case could become "hot" and could knock the heck out of your if you touched it. But all you need to weld is the two phases and ZERO current flows in the green wire. Again there is NO common.

 

[K5lwq]

I think terminology is what is confusing reading some of these post.

I always referred to individual legs of electricity for incoming power. Two separate legs create single phase 220v power. One leg to neutral or a ground will provide 110v. Three separate legs create three phase.

Often in 220v control circuits one leg is referred to common and the other as signal. All the commons tie together in the circuit.

Maybe I have been wrong all these years but I usually can troubleshoot and fix most electrical issues. :confused3:

 

[jaxs]

I simply read nomenclature plate on welder or compressor motor or appliance and use a voltmeter to verify that the voltage is correct for application..... And have really basic understanding of how 120 VAC and 240VAC supply circuits are wired.... Has always worked for me.... 38 years in telecommunications and above concepts have never failed me...

But the pissing match is entertaining...

Dale

I think terminology is what is confusing reading some of these post.

I always referred to individual legs of electricity for incoming power. Two separate legs create single phase 220v power. One leg to neutral or a ground will provide 110v. Three separate legs create three phase.

Often in 220v control circuits one leg is referred to common and the other as signal. All the commons tie together in the circuit.

Maybe I have been wrong all these years but I usually can troubleshoot and fix most electrical issues. :confused3:

That's what a hvac tech,appliance repairman and automobile mechanic does every day so why would diyers need to be be any different?