welding on vehicles

[Hank33]

I got a rare opportunity of talking to a design engineer for a piece of equipment. One of the things he mentioned was the battery, also bad grounding, etc. He mentioned that diodes are usually what gets smoked when something goes wrong with welding on a equip/vehicles. Sometimes though it is worse.

He made it clear that it is rare to have any troubles, but it can be very costly. In most cases it is not very much work to take the recommended precautions. Time well spent IMO

[browncoat]

man, I forgot one important point on my previous post. The battery is the one shop stop, BIG THING (tm) that is connected to all powered devices through the ground, or through the positive bus. That being said, disconnecting the battery positively opens the circuits that are supposed to be there. In terms of 80/20 rule thinking, unhooking the ground post is the 10% of the effort that gets you 90% there.

(I also agree with previous posts. Things can still go wrong because everything is on the bus and ground. Anything like shorts, weak components, etc. but you would most likely have other symptoms of such things already. Stuff that did not work correctly, or at all. Wires with insulation burnt off, etc. Not to mention the potential for static charge build up. Forgive the pun. )

[William McCormick Jr]

If your ground from your welder goes bad. And ARC's. The insulation of any wires, that run through switches and are isolated from the battery or ground, will become parts of a capacitor. If this takes place and your batteries are hooked up. You can get high frequency ARC accompanied by battery power. I get that sometimes in outlets. That is why some manufactures recommend disconnecting the battery.

When wires that are not connected to the ground or the battery are subjected to arc from or to the chassis, the floating wires whose insulation is up against the chassis, can charge to voltages that can jump switches (switches are air capacitors). A switch with points works by creating an air capacitor, that stops the flow of electricity across the points. Some electricity flows to create the air capacitor that stops the flow of electricity.

You Tube

You Tube

Here is a movie showing how a capacitor once charged stops electricity.

You Tube

You Tube

It is so funny but you need electricity to make an insulator work. Some electricity has to flow through the insulator. Or it would not insulate.



Sincerely,


William McCormick

[worntorn]

William, I sent you a PM re pedal.

Glen

[tstrboy2004]

newer vehicles I do when doing exhaust work.

older vehicles not so much..

you should also disconnect the wiring at the ECU to be extra safe

[pandinus]

Loved those videos... They are a fine example of someone with limited knowledge sharing assumed/inaccurate information.

By definition an insulator is a substance that does not transmit heat (thermal insulator), sound (acoustic insulator) or electricity (electrical insulator).

An insulator does not require electricity to work, quite the opposite... depending on the insulator the higher the potential difference, the higher the likelihood that the insulator will fail...

In a perfect world a perfect insulator would conduct no energy, in the case of electricity glass is pretty good, but impurities lower the resistance of the insulator allowing energy to leak through which gives you the breakdown level of the insulator... the more impurities the more energy will flow through it.

In the case of an electrolytic capacitor an electron flow is what makes them work. As electrons (a current) are introduced to the capacitor they rush towards the positive charge where they meet a very thin insulator that resists their ability to travel from the negatively charged medium to the positively charged medium to the point where the negative charges of the electrons repel each other, the higher the voltage applied to the cap the thicker that layer of electrons will get storing energy... eventually the potential difference will be high enough for the electrons to jump through the thin insulator most likely destroying the film and the capacitor becoming a short, then an open an the electrolytic medium is vaporized.. In the case of the polarity being reversed though the electrolytic fluid, it can boil very quickly causing the cap to explode... paper everywhere lol

In the case of a diode a positively doped semiconductor is placed in direct contact with a negatively doped semiconductor... when electron flow is introduced in the direction of the positively doped side the negatively doped side repels the electrons and again an excess of electrons build up in the depletion region and further restrict the flow of energy.

An open switch more directly resembles an antenna than a capacitor... An AC signal on one side of the air gap will induce a magnetic field that will be picked up by the conductive elements on the other side, and converted back to an electron flow. This is why the oscilloscope probe picked up the signal without being attached to the circuit.
AND PUTTING ONE HAND ON A LIVE CIRCUIT AND THE OTHER HAND ANYWHERE like he did in the video IS JUST PLAIN STUPID.. it takes micro-amps to stop your heart... one of the lessons I was given in school was whenever investigating a circuit, probing for voltages, moving wires, touching anything unless you know for a fact the circuit is dead.... KEEP ONE HAND IN YOUR POCKET... that way any stray current you encounter won't flow through your chest and you wont be dead!!!

A majority of people have no idea that electrons flow from negative to positive and that conventional current flow as still used today was a guess during the discovery of electricity that had a 50% chance of being correct... THEY WERE WRONG...

I'm going to try and get off the soapbox now lol

I could go on but you get the idea.... and I am not about to try and tell anyone how to make X-Ray quality pipe welds because when it comes to welding I'm not far from "the metal heats up and melts together"

I came here to learn and assume most of the information is accurate, and that when it's not someone will point it out

[William McCormick Jr]

You claim I am wrong with nothing but opinion.

All thnigs in this universe conduct electricity. It is just a question of how much, why, and how.

Now my intention is not to cause a misunderstanding at all.

But you went on about AC current. Being radio instead of DC pulses.

That same switch works the same way with DC power. No radio like wave forms at all.

So I will stand rather comfortably on the fact that a switch is an air capacitor. And it does require power to work. It must be charged.

In fact as you are charging an insulator, it becomes a stronger and stronger insulator. Because you are charging it. Sure when you reach that voltage that causes it to break down it will break down.

Some of the best shocks are when you go to charge an insulator. And it draws a lethal current to become an insulator. Much like your explanation of a capacitor.

A diode is also a miniature capacitor. That must be charged up in order for it to stop a flow of particles of electricity. Very much like a battery, but with very little storage.

You can watch a diode on an oscilloscope try to stop the flow of AC current. It cannot, until you put a load on the circuit that maintains enough particles of electricity on the diode to keep it functioning. Or better put, keep the diode charged.

What I am saying it true.





Sincerely,


William McCormick

[William McCormick Jr]

You actually debunked your own information with your explanation of the capacitor. There are two plates in a capacitor separated by an insulator or better put a dielectric. According to you no flow of current is going to take place through an insulator.

I can tell you flat out that, if an insulator stopped the flow of electricity, your capacitor will not function. It will draw no current. Store no power. They use the insulators love of slowing conduction. To cause it to create an abundance of particles of electricity on one side of the capacitor. And to hold a shortage of particles of electricity on the other.

The actual explanation of how an insulator works on a particle level, requires the knowledge of Universal Science. I think we should just stick to the basics though.

Sincerely,


William McCormick

[William McCormick Jr]

You are right about most people not knowing that particles of electricity flow from the modern car batteries negative terminal to the positive terminal.

However Benjamin Franklin had it right. Later experiments with cathode rays and ARC rays confused the actual direction of them. And it was colleges that set the direction of electricity by calling the terminal abundant with particles of electricity negative. Franklin got it right. America was right on.

Recently an English fellow I was talking to was saying that in England many of the scientific decisions were made, simply because England did not want to be following America's lead. England was sending young children to Church Bell towers to die, while ringing the church bells to ward off lightning. While they were denying the success of Benjamin Franklin's lightning rod. Benjamin Franklin ended up winning England's highest scientific award the Copely award. With a working lightning rod.

England would just do things in reverse to America. Just to be different. However if you look at Benjamin Franklin's work. It is amazing. He was electrocuting Turkeys for festivals. Energizing rivers with lethal energy, and had an electric spit to cook Turkeys all before the Revolutionary War. He was further ahead of where we are now with understanding electricity.

Franklin's definitions can only be confused by those that really do not understand electricity. His was the single fluid theory. Where an abundance of particles of electricity flowed to a shortage of particles of electricity. Since particles of electricity repel each other, there is a pressure created by an abundance of particles of electricity, that wishes to flow to a shortage. Or an area with less particles of electricity.

Only colleges could have gotten that one wrong.

Benjamin Franklin's lightning rod, was a diode. Along with the air it created a diode that could repel the ARC ray from the clouds. If lighting was just an electrical charge. It would move very quickly and in a perfectly straight path. However lighting is an ARC much like a cathode ray in a television tube. That is why you can steer it.

You cannot steer electricity heading to a terminal. You can only steer cathode rays, not heading for a specific terminal. Cathode rays are free rays that you can steer with very low voltage, even heat. That is why a lightning rod can steer lightning away from a lightning rod.


Sincerely,


William McCormick

[pandinus]

"You claim I am wrong with nothing but opinion."

Sorry your right, I only have the "opinion" of all my Professors, textbooks, and all the Electronics/Electrical Engineers and Physicists out there... but they don't count for much now do they??? Sure we all used to believe the world was flat (not me personally!!) but sometimes the majority is proven wrong through seemingly unbelievable advances in science...

Oh and please tell how the capacitor would store energy if electrons (oops electrical particles) were allowed to conduct straight though it without any resistance/insulation??? That is exactly how a capacitor works... the electrons are not allowed to flow through the insulator and are stored within the conductive medium itself!!! otherwise its just another wire. when you charge a capacitor, it has an EXCESS of electrons on the negative "plate" because they are attracted to the lack of electrons on the positive plate, but cant get there.

Think about two magnets,,, separated by a piece of wood... is there no attraction between them because there is a non magnetic medium between them??? It gets more complex with electricity as electrons have a point charge (meaning they are negatively charged only) and repel each other. They don't have a "north and south" like a magnet. But a moving electron does have a magnetic field... that's part of the reason a welding arc reacts to magnets...

Yes I agree with you Electronics do require a basic knowledge of sciences... I'm sure you have much knowledge that I could learn and benefit from. I don't want to start reciting several years worth of electronics math and physics on a welding forum, but I do believe on this subject I might actually have one up on you...

I just want to mention that this is not a personal attack on you, you do have a lot of great information,,, just some of it is a little misinformed... Hey I'll admit i have some things wrong also... that's life

[PapaLion]

Electricity is our friend... not our GOOD friend but our friend

[pandinus]

The best part Is we don't really know much on the subatomic level yet.. so maybe an electron does have a positive charge, just weaker then the nagative, or it could be internally positive externally negative... maybe equally charged but spinning so fast that it the negative charge appears stronger??? I could speculate for hours, but for now I'll go with what has been proven so far and what part of that I do understand.

[pandinus]

If anyone knew anything about electricity it was a man named Tesla... but from what I understand he took most of that knowledge to his grave as he thought misused, it could destroy mankind... just like ATOMIC energy...

[jsfab]

Originally Posted by farmersamm

Did someone say Google??

Anybody who's interested should do a Yahoo search with the tags:.......aftermarket bodybuilder bulletin ford pcm abs

Simply disconnecting power cables doesn't isolate the PCM. The harness provides a pathway for current. Maybe you can get away with it 100 times, but the 101'st could be expensive.

https://www.fleet.ford.com/truckbbas/topics/qvmp.html

Scroll down the page a bit, this is straight from Ford. Q-123R1 and R2. Both are PDF documents.

These simply say what Ford wants you to do when welding on their trucks. That being said, I know plenty of guys with late-model Ford welding rigs, that weld on the back of their trucks all the time, no problems.

As I understand it (not from these documents) there are two possible ways of creating damage from arc welding. One is from high frequency AC, the other (more common) is from residual magnetism created by DC welding, with nowhere to go when you break the arc. In neither case, would just disconnecting the battery be enough to protect the computers from damage. I would have more faith in one of those spike protectors mentioned earlier in this thread.

Whatever anybody thinks, computer damage is never, or very rarely, from stray arc voltage meandering it's way thru and around the computer, if it was, you would have a smoking lump of melted plastic, and melted wires, not just a couple blown diodes or capacitors.

[farmersamm]

It's interesting about the AC thing. You're the only other one who's brought it up.

When I smoked the ECU on the 1 ton I was using AC for tacking, then doing the finish welds on DC. I brought this up earlier in this thread, and wondered if the AC current possibly defeated the diode protection on the ECU power supply connection.

But, I don't think regular AC stick welding is high frequency though, or is it? Dunno

[William McCormick Jr]

You explained how a capacitor draws power into it. You have two plates separated by a thin dielectric.

Now if you take those same two plates and replace the dielectric with air, you do not get much of a capacitor. You still get an air capacitor, but at very reduced storage capacity. So we know right away that the lesser insulator or better put, dielectric is the cause of the capacitor. The lesser insulator makes a better stronger capacitor. Air is the best insulator, mica, and glass are lesser insulators.

http://www.Rockwelder.com//Electrici...apformula.html

A slight flow of electricity is what causes the capacitor. Often capacitors are not made with the best insulator. They are made with the best dielectric, having less insulating qualities, then worse dielectrics (better insulators).

When the flow starts through the insulator or dielectric, it scrambles to stop the flow. By charging up with an abundance of particles of electricity on one side of the capacitor, and a shortage upon the other. It creates a force, an energy when it does this.

You need Universal Science to understand it though.

Your Namby Pamby College professors have allowed for many years this charade to go on. To a point our labeling is in total chaos.

When I learned about atoms of water flowing in a river, I learned that the current of water is from the highest part of the river to the lowest part of the river.
When I learned about a current of air, I learned that the air flowed from the highest pressure of air to a lower pressure of air. Same with fluids and everything else.

Now we take your professors, teachers, and mentors, labeling of electricity. They call the terminal abundant with particles of electricity, abundant with electron potential, and electric pressure, the negative terminal and give it a (-) symbol.

They claim that the particles of electricity, flow from the (-) terminal to the (+) terminal. They say the flow of electricity the particles of electricity, are from the (-) terminal to the (+) terminal.
But then, they say, the current of electricity, is from the (+) terminal to the (-) terminal, and is measured from the (+) terminal to the (-) terminal. Wow!

I say either throw out the English language, or admit that a bunch of bumbling cowards were not even up to Benjamin Franklin.

Miller, ESAB, and Lincoln welding, you should take five shots with a paddle on national TV as well.

There was never an ounce of proof that the particle of electricity is negatively charged. That was just an after thought or damage control to moving away from Benjamin Franklin's perfect understanding of electricity.

And you avoided the air capacitor totally. You did not mention that you do not need radio pulses to communicate through air. That the original diagram I gave is that of an air capacitor. And what takes place between points in air is an air capacitor.

http://www.Rockwelder.com/Electricit...apacitors.html




Sincerely,


William McCormick

[William McCormick Jr]

Originally Posted by jsfab

Whatever anybody thinks, computer damage is never, or very rarely, from stray arc voltage meandering it's way thru and around the computer, if it was, you would have a smoking lump of melted plastic, and melted wires, not just a couple blown diodes or capacitors.

The problem is the bad ground. It can cause your whole truck chassis to polarize instantly back and forth. Hundreds or thousands of times a second. That can be too fast for gates in transistors, to match the transistors ambient voltage. That can cause them to turn off or turn on. In either case you can get some weird stuff taking place.

For fun sometimes I shut off electronics with an abundance of particles of electricity applied to the gate. It does not take much.

Having the welder on the truck probably helps. Believe it or not. It becomes a stabilizing force, a heavy neutral if it is well grounded.

Sincerely,


William McCormick

[Mad about Metal]

I got lazy one day and decided it was safe enough not to disconnect the battery on the old mans car and just ground nice and close to the weld.... BIG MISTAKE, weld went great but then trying to start the car??? As a mechanic I checked and found that the ECU was blown, ABS computer was fried and the battery had been cooked...... Ended up costing me $2500 for the ECU, $1300 for ABS computer and another $150 for a new battery and the work only got me $26 so I made a loss of $3924 if my math serves me right.... The car was a newer one it was a 2008 Toyota.. Taking the battery off empties the wires of a current so that if there is a problem with a bad earth somewhere you won't short them and if the wiring is dead then well ummm how is it gonna fry? Because it needs active and earth for it to run but if its only getting one then nothing can or will happen, my sources? Common sense, training as a mechanic and further trainin in auto elecs and finally my instructors

[jworman]

Originally Posted by Sandy

I polarized my old 51 Willys welding on the spring hangars with a bad ground. Had to sell it after that. Dayhem thing would only go north and south, didn't have the horsepower to east or west in high range. Too slow getting anywhere in low range.

Ohh, I've seen a lot of old Jeeps like that. You didn't even have to weld on them to get the low horsepower.

[cmartman46]

I would be more concerned with DC welders. But ground close to work. And disconnected battery ground and any computorized devises would'nt hurt.
I did see a couple of coworkers weld steel frames on forklifts while the forklift was still running.
I would'nt do it personnally but some people dont like constructive critizizum(LOL)spell check!