Understanding 12 volt wiring. The basics!

Rusty Panels

Well-Known Member
@Rusty Panels , the wiring in my old Disco is a dogs breakfast after years of dodgy work done by multiple people, sadly including me, feel like dropping over for a BBQ and a afternoon or two of fixing, I just couldn’t be bothered after spending all week installing cabling and equipment
Love to help you out Matt but the tyranny of distance and all the restrictions make that a bit difficult. You just need to get motivated and get those wire cutters snip, snip snipping! Disconnect the earth wire fist though ! ;)
 

Rusty Panels

Well-Known Member
After all that I said today I must report that I blew it! I literally blew my alternator, or at least I cooked it!
I had a new clutch put in a few weeks ago and had the rear main oil seal replaced at the same time. The rear main was leaking as the mechanic said (yes I went to a mechanic!) (4wd boxes have always frightened me due to their size and I don't have one of those big gearbox jack things). Apparently the rear main had been replaced and was not sitting square so therefore the leak. If there's one thing I hate it's oil leaks. Despite the rear main being replaced the oil spots on the garage floor persisted. As there was quite a bit of old oil still laying in the nooks and crannies I decided yesterday to give the old girl a good dose of degreaser followed by a good hose down. That all went well and I was convinced that I had probably solved the oil spots on the garage floor problem.
Took the cruiser for a run into town this morning and being that it was a very warm day had the aircon running and the windows up. I also had the music pumping through the recently installed Pioneer and sub woofer so, I was in a happy place.
I had travelled about 10 k's in my happy state when all of a sudden the music stopped I glanced at the dash and found that not only had AC/DC ceased to belt out of my speakers but the speedo, tacho, fuel, oil, temperature and every other gauge and function had also stopped. The engine was still running thank goodness.
The only circuit that worked was the headlights (no tail lights, indicators or brake lights). I turned around and went home hoping that the cops wouldn't spot me.
After a bit of checking and a lot of thinking I checked the black box that is mounted on the positive terminal on the starting battery. It is a square plastic box about 75 x 75mm. I ended up pulling it apart and found that it is in fact nothing more than a big fuse that feeds 4 connectors and also has a terminal that comes from the alternator. It had a fused section on it that fed 3 of the 4 connectors. After a bit of checking with the trusty multimeter I came to the conclusion that the wire that came from the alternator may be the problem.
When I managed to get a better visual on the alternator I could clearly see that there was a quantity of burnt material on the windings.
Obviously there was a problem with the insulation on the windings. I don't think that I sprayed an excessive amount of water in that area. In any case an alternator should be able to handle complete submergence without becoming a molten blob.
Anyway, the new one has been ordered so here we go again.
 

Bru9

Active Member
Except it turns out that is wrong too. Current doesn't flow inside a conductor at all. Forwards or backwards. Nothing moves and there is no flow of current. The flow is not electric, its magnetic, and happens outside the conductor in the insulation and air. Magnetic forces make it look like there is a current flowing along the conductor, but there isn't. Measuring current is an illusion. That's why hall effect devices, transformers, motors and generators work.

So if that makes sense, you get how electricity works.

Now is light a wave or a packet or both or neither?
Well Current does indeed flow inside the conductor, Current is the flow of charges (electrons), there just has to be alot of them moving in a similar manner to constitute Current. When electric charges move along the wire they give rise to a helix shaped magnetic field around the conductor, that is what the clamp meter is working with. Current (electron flow) always flows from the "negative" to "positive", the speed of electron flow is very slow as they continually collide into atoms (ions) and interact with each other (like chargers repel) with DC, and doesn't move with AC.
By analogue, air molecules are the electrons, and the sound which is the actual energy traveling through the medium is like the electricity that uses the electrons. But without this picture you could never explain a spark or how the actual light filiment gives off light.

The actual electricity or electric charge or energy that powers our loads travels through the electromagnetic field via the electrons, you can't have one without the other. It always flows in one direction with DC from source to load (same with with AC excluding reactive power). The law of induction is that a moving permanent magnet exerts a force on the electrons in a closed circuit.

Light and matter are both wave and particles, depending on which experiment you setup. That's all physics can say before going into philosophy. What actually is going on "in between" some have argued is meaningless or can't possibly be answered and nature is absurd and as they say "nobody understands" But what modern physics refers to as waves and particles is very different from the older days like bullets or corpsicles. A wave is used to describe the behaviour of the results on the screen, only way to understand those results in the double slit experiment is to simply say light has a wave nature to it, yet strangely the photon imparts it's momentum in a single well defined spot, what's worse is these particles have no dimension they simply are point like. The truly mind blowing thing is where these impacts occur (the distribution) is probablistic, in that you run the experiment for a billion years and you will always get a random pattern. So is nature probablistic? Are we made of atoms/real physical objects? Or are we perhaps made of numbers?
Ahhhh those are some of deepest casims in all of metaphysics.

Good luck :D
 

Mick_Marsh

Active Member
Except it turns out that is wrong too. Current doesn't flow inside a conductor at all. Forwards or backwards. Nothing moves and there is no flow of current. The flow is not electric, its magnetic, and happens outside the conductor in the insulation and air. Magnetic forces make it look like there is a current flowing along the conductor, but there isn't. Measuring current is an illusion. That's why hall effect devices, transformers, motors and generators work.
Yet more disinformation on the internet.
A little knowledge can sound right, but is wrong.
Electrons do flow in a conductor. Well, in DC applications. The current flows at the speed of light, however, if you wanted to track an individual electron it is much slower. 4m/s I think.

The flow of electrons outside the conductor in the insulation and air is a thing called "skin effect". This occurs in AC transmission systems. With the electrons moving back and forth (yes, the electrons move) they create a magnetic field that restricts their movement. The magnetic field is concentrated in the centre of the conductor and reduces the greater the distance from the centre. Skin effect also increases as frequency increases.
The current flowing in the air is more to do with ionisation.
 

discomatt

Well-Known Member
Popcorn with plenty of butter please, I know where electrons flow due to the work and training I have done over the last 25 years but find it more interesting to just read and sit back these days, no point in arguing with some people :)
 

boobook

Well-Known Member
Do your own research.
And agreed - no point your arguing, if you don't know what you are talking about. :)

If you want a discussion on it, start with facts, not insults and bragging about your training.

And if you want to start with qualifications in the subject, I studied at Uni for 4 1/2 years doing an Electrical Engineering Bachelor's Degree. What is your training?

If you don't understand it, that's ok. I wouldn't expect some to, based on previous 12v posts that show a clear lack of how things work. In fact, it is actually a difficult concept to grasp, which is why conventional theory is used most of the time. ( Holes flow in the conductor. without thinking about holes, semiconductors cant work, and I am pretty sure they do .)

Is there any more butter? The trouble with popcorn is that you have a little bit, then want more.

Post up your qualifications then let's discuss it sensibly. Or just look at reliable contemporary reports on how it works.

If you want to continue with thinly veiled insults, we can do that too. At least my posts aren't being modified without my knowledge or permission anymore.

More Popcorn?
 
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discomatt

Well-Known Member
@ boobook Why assume I was referring to all your comments??
I know your training in electronics, as I know where electrical current runs in or around a conductor it was a renal comment about discussion on social media.
the references to popcorn was in anticipation for your reply to Mick
 

boobook

Well-Known Member
@ boobook Why assume I was referring to all your comments??
I know your training in electronics, as I know where electrical current runs in or around a conductor it was a renal comment about discussion on social media.
the references to popcorn was in anticipation for your reply to Mick
What makes you think I was referring all my comments to you?
 
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