Why is a grounded workpiece called "Reverse Polarity"?

# Thread: Why is a grounded workpiece called "Reverse Polarity"?

1. WeldingWeb Journeyman
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## Why is a grounded workpiece called "Reverse Polarity"?

Probably a stupid question, but this bothers me.

Normally, I ground the workpiece and attack it with the electrode. So normal = reverse?
(Let's ignore the fact that I only have an AC welder for a second...)
It just seems like one would logically think that the workpiece would "normally" be grounded, not hot, and the active part you are using would be the hot part. So calling the reverse of that "reverse" doesn't make much sense to me.

Anyway, I guess I could live be being told that it's just that way, but I just read something else...

I just read that the reason Reverse Polarity means a hot electrode is because electrons flow from the ground to (+). This is what actually bothers me:

No other engineering discipline in the world uses that convention. We all know it's true, but EVERY SINGLE OTHER FIELD uses a system that follows "hole flow". Even electrical schematics indicate diodes with arrows indicating the flow of positive current. Please, someone tell me that the weldors didn't decide to just be different from everyone else. Please tell me that there is no real reason behind the Reverse designation. Or maybe the first welding machines only did Straight polarity, and so they later designated EP as reverse. But please don't tell me that unlike every other mechanical or physics field, they decided to base welding on the direction of electrons.

2. ## Re: Why is a grounded workpiece called "Reverse Polarity"?

Electrons flow from "negative" to "positive" ...if I remember electrical theory correctly!

therefore, "normal" flow would be from your tungsten (tig) or your electrode (stick) into your workpiece. The electrons would be flowing from the torch into the workpiece....from negative to positve (electrode negative).....or straight polarity.

I think what makes it "wierd" is because of the use of a "ground clamp." We always think of a "ground" as being negative. So, visually, you see your ground clamp, and you naturally think of it as the "negative" in the system.

3. ## Re: Why is a grounded workpiece called "Reverse Polarity"?

BurningMetal hit the nail on the head Skippii. At least you were willing to ask in an effort to understand. Try explaining it to someone (a seasoned weldor) who refuses to accept basic electrical facts.

4. ## Re: Why is a grounded workpiece called "Reverse Polarity"?

skippii,
If you remember from basic electrical classes:
Conventional flow is from Positive to Negative.
Electron flow is from Negative to Positive.
Let's blame this confusion on Benjamin Franklin. He described flow from a positive source to a negative source. It wasn't until years later after technological advances lead to the discovery of the electron that it was proved that electron flow is from negative to positive. However, by that point, tradition was already firmly established (even though it was wrong).

Like BurningMetal said, just because it's called a ground clamp, doesn't necessarily mean it is negative.

In the case of MIG, the gun is DCEP (Direct Current Electrode Positive) and the ground clamp is negative. In the case of Fluxcore (same machine reversed leads on the inside), the gun is DCEN (Direct Current Electrode Negative) and the ground clamp positive. So you see, in this example positive and negative can change based on the weld process (MIG vs. Fluxcore) and internal lead arrangement.

5. WeldingWeb Foreman
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## Re: Why is a grounded workpiece called "Reverse Polarity"?

Actually, straight and reverse polarity have nothing to do with electron flow.

The names came about from bare wire welding and carbon rod welding. Both are run electrode negative. Bare wire because it is darn near impossible to control otherwise, carbon rod because the carbon spits and contaminates the weld if run electrode positive.

Ref: 1938 Hobart Arc Welding Handbook; Machinerys ref series vol 127 (http://books.google.com/books/downlo...Mdx5CnJs2tDpJA See page 4: Bernardos process)

6. ## Re: Why is a grounded workpiece called "Reverse Polarity"?

Reverse Polarity= Rod Positive the to RP's go together, that's the way it is and I quit trying to explain it and confuse everything once I graduated.

7. ## Re: Why is a grounded workpiece called "Reverse Polarity"?

Originally Posted by enlpck
Actually, straight and reverse polarity have nothing to do with electron flow.
???

The very word 'polarity' infers the poles of an electrical circuit and electrons flow from the negative pole to the positive pole. Obviously in the welding process the poles are the work piece and the electrode (whether stick, wire, tungsten, etc.) and the 'straight' / 'reverse' references are simply supposed to keep everyone on the same page. Well that certainly hasn't happened over the years (probably in part due to modern automotive wiring) so the use of DCEN (straight) and DCEP (reverse) has been adopted in an effort to eliminate confusion on the part of those who don't understand electrical principles.

http://en.wikipedia.org/wiki/Electrical_polarity
Last edited by duaneb55; 03-06-2010 at 10:22 AM.

8. ## Re: Why is a grounded workpiece called "Reverse Polarity"?

Originally Posted by tresi
Reverse Polarity= Rod Positive the to RP's go together, that's the way it is and I quit trying to explain it and confuse everything once I graduated.
That'll work tresi. Easy enough to remember if one is having trouble keeping the two 'straight'.

9. WeldingWeb Craftsman
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## Re: Why is a grounded workpiece called "Reverse Polarity"?

Skippii, Skippii, Skippii, Skippii, stop thinking so much, stay in bed another hour.
The term, “Ground” is thrown around with every change of the wind. The “ground” clamp doesn’t ground anything. The clamp and the wire attached to it is the current return path to the secondary coil in the transformer and NOTHING MORE. Transformer OUT>welding cable>rod clamp>rod>arc>work>GROUND CLAMP>welding cable>transformer IN, all forming a closed loop. Don’t believe me? Check for continuity from the GROUND pin on the power plug to the “GROUND” clamp.

10. ## Re: Why is a grounded workpiece called "Reverse Polarity"?

This should have stopped at Burning Metal's explanation. If I read anymore, I will stab my eyes.

11. ## Re: Why is a grounded workpiece called "Reverse Polarity"?

Holy Crap.... WAY too many people trying to sound like rocket scientists - And NO, it's NOT working.... LOL

Might be easier to replace "Ground" with "Work Lead".... Just to sort your brain out.

So you have the Elecrode, and the Work Lead....

Whatever is "Positive" will be the hotter of the two...

Straight Polarity - DC Electrode NEGATIVE - Work Lead (Work piece) will be "Hotter" than Electrode.

Reverse Polarity - DC Electrode POSITIVE - Electrode will be "Hotter" than Work Lead (Work piece)

As to the Specific Scientific Explanation - WHO CARES? - In the end, I just need to know how to hook up my cables to get the job done.

Don't make Welding harder than it needs to be fellas.
Last edited by Black Wolf; 03-06-2010 at 11:17 AM.

12. ## Re: Why is a grounded workpiece called "Reverse Polarity"?

I generally stay away from referring to specific processes for the exact reason that was demonstrated in a previous post - The member claimed that GMAW (Mig) is Electrode Positive, wile FCAW (Flux Core) is Electrode Negative....

This Information, while well intended by the member, is FALSE.

FCAW(Flux Core) Dual Shield (With Gas) is Normally Electrode Positive same as GMAW.

FCAW(Flux Core) Self Shield (No Gas) is Normally Electrode Negative, the opposite to GMAW

Don't take MY, or ANYONE'S word for it, read the Manufacturer's Recommendations on the product packaging.

13. ## Re: Why is a grounded workpiece called "Reverse Polarity"?

Originally Posted by Black Wolf
This Information, while well intended by the member, is FALSE.

FCAW(Flux Core) Dual Shield (With Gas) is Normally Electrode Positive same as GMAW.

FCAW(Flux Core) Self Shield (No Gas) is Normally Electrode Negative, the opposite to GMAW

Don't take MY, or ANYONE'S word for it, read the Manufacturer's Recommendations on the product packaging.
When I mentioned Fluxcore, I was referring Fluxcore without shielding gas which is DCEN.
My bad for not specifying Fluxcore with and without gas.

Ahhhhhhhhh!

14. ## Re: Why is a grounded workpiece called "Reverse Polarity"?

No Worries Boss...

I wasn't meaning to single you out, or pick on you for it.... But it is very, VERY, easy to make small mental mistakes like that when we are explaining things to others.

I am aware that you know what you are talking about on this topic, and know what you intended, but when typed in that form as an "Absolute" it is incorrect, and misleading.

Have a Good Day.

15. ## Re: Why is a grounded workpiece called "Reverse Polarity"?

I try to avoid talking "reverse/straight polarity" when talking to other welders. It is easier and more straight forward to speak of the electrode (or torch) polarity. ....... either EN or EP. then, there's no confusion.

16. ## Re: Why is a grounded workpiece called "Reverse Polarity"?

I try to avoid talking to other welders, OR co-workers for that matter!

I like to hook up the Air Arc and send 'em ALL running away SCREAMING!

ROFLMAO

Have a Good Day.

17. WeldingWeb Apprentice
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## Re: Why is a grounded workpiece called "Reverse Polarity"?

For an easy way to tell which polarity to use go to the bathroom and pour some water down the drain. If it runs down the drain clockwise use straight polarity. If it runs counter-clockwise use reverse polarity. Or if it just gurgles use alternating current.

18. ## Re: Why is a grounded workpiece called "Reverse Polarity"?

Because that is the way the electrical gods made it.

19. ## Re: Why is a grounded workpiece called "Reverse Polarity"?

This has been very entertaining...

...zap!

20. WeldingWeb Journeyman
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## Re: Why is a grounded workpiece called "Reverse Polarity"?

Originally Posted by RandomDave
For an easy way to tell which polarity to use go to the bathroom and pour some water down the drain. If it runs down the drain clockwise use straight polarity. If it runs counter-clockwise use reverse polarity. Or if it just gurgles use alternating current.
Thanks for the new sig.

21. WeldingWeb Journeyman
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## Re: Why is a grounded workpiece called "Reverse Polarity"?

Originally Posted by enlpck
The names came about from bare wire welding and carbon rod welding. Both are run electrode negative. Bare wire because it is darn near impossible to control otherwise, carbon rod because the carbon spits and contaminates the weld if run electrode positive.

Ref: 1938 Hobart Arc Welding Handbook; Machinerys ref series vol 127 (http://books.google.com/books/downlo...Mdx5CnJs2tDpJA See page 4: Bernardos process)
Now this is exactly the kind of thing I suspected and hoped it might be. You're saying that the earliest forms of welding all used the same way, so when they started with other polarities, it was the reverse of what had been done in the past? Makes complete sense.

22. WeldingWeb Foreman
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## Re: Why is a grounded workpiece called "Reverse Polarity"?

where's mc cormick with a polarized lightning strike story ?

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## Re: Why is a grounded workpiece called "Reverse Polarity"?

I think I saw this here, back in the day rods were typically dcen so on welders the stinger was always on the "neg" or - and the work clamp was on the "pos" or + , with newer technology and improved rods and coatings they started making the rods run off of dcep so you would reverse the cables hence the name reverse polarity, I could be wrong though so don't take my word for it hahahaha

24. WeldingWeb Journeyman
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## Re: Why is a grounded workpiece called "Reverse Polarity"?

Originally Posted by RandomDave
For an easy way to tell which polarity to use go to the bathroom and pour some water down the drain. If it runs down the drain clockwise use straight polarity. If it runs counter-clockwise use reverse polarity. Or if it just gurgles use alternating current.
do us welders in the southern hemisphere need to do the opposite?

25. WeldingWeb Foreman
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## Re: Why is a grounded workpiece called "Reverse Polarity"?

Originally Posted by enlpck
Actually, straight and reverse polarity have nothing to do with electron flow.

The names came about from bare wire welding and carbon rod welding. Both are run electrode negative. Bare wire because it is darn near impossible to control otherwise, carbon rod because the carbon spits and contaminates the weld if run electrode positive.

Ref: 1938 Hobart Arc Welding Handbook; Machinerys ref series vol 127 (http://books.google.com/books/downlo...Mdx5CnJs2tDpJA See page 4: Bernardos process)
And from this the straight way came into use to describe the welding procedure.

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