Please explain...

[chh]

How is this guy not getting electrocuted?
He is shorting out the output of a coil....what am I missing??

~3:40

https://www.youtube.com/watch?v=Vpsvmei6t7E&list=UUBFI1mrpMg8EETeRZv0YTNA

 

[alwaysFlOoReD]

Power always finds the easiest way to ground. He isn't it. The human body isn't a real good path for electricity but you still have to be careful to not make yourself the easy way to ground.

 

[adsm08]

Not only is he not the easiest path to ground, he isn't even part of the circuit. The wire he is holding is grounded somewhere, since the wire allows a much easier path to ground that the insulation around it he isn't even part of the circuit.

Add to that the conductive properties of the human body, and it is almost impossible for you to kill yourself by accident with an ignition coil. But I can show you how to do it with a 9v battery.

The human body is actually a wonderful conductor, being that we are full of fluids, electrolytes, and iron. Human SKIN is a very good insulator though, and current tends to flow along the skin since it can't readily penetrate any deeper. This keeps the heart and brain out of the direct path of the current. When one of those organs is in the direct path that is when you get electrocuted.

I have been zapped many times by ignition coils, your arm goes numb and your heart rate rises a bit, because you overload the nerves at the surface and that triggers an adrenaline rush. But if it can't get under the skin and out the other side the vital organs are out of the direct path and won't be damaged.

Now, if you take your ohm meter and just hold both leads in your fingers you will get a reading. It will vary from person to person based on a few factors, my own reading is about 24,000 ohms. You won't even feel it. The reading you get is the resistance of your skin.

Next, if you have braces touch the leads to your braces. You will get a much lower reading and feel a slight tingling in your mouth. Saliva and the steel of the braces are conductive.

Finally, take the leads put them in holders on the table so they face straight up and are held firmly. Stab them into your palms. The reading will be almost zero, and because you have let the current under your skin and a straight line drawn through the body from one point to the other crosses the heart you will die.


Also, voltage doesn't kill, amperage kills. Those coils are putting out about 40,000 volts, and almost no amps.

 

[ab_slack]

The arc is going to the clip which is shorted to ground in the first case. That fact that he is touching the clip wires is completely incidental, he never sees anything other than ground (chassis) potential.

In the latter case, as long as the bolt for the coil isn't the only return path for the coil secondary such as one of the low voltage drive leads, the spark arcs to the block and completes the circuit. He is holding the outside of the coil away from the high voltage element so isn't hit by it.

I don't know how typical that configuration is. It may be the norm, I haven't worked much with coils like that. I wound probably check out diagrams and maybe an ohm check or two to make sure there was a return before I would try something like that.

 

[adsm08]

That setup is not terribly typical, it looks like it is a Kia dual-spark system, which are odd buggers. On a 6-cyl like that it's more for emissions, like the dual-spark system used on the 2.3 and 2.5. On the 4-cyls it's a paired set up cylinders in a waste-spark system.

It looks like the boots are bad on those wires. As for the typical operation of a COP (coil-on-plug) it's just like the 2.9 and early 3.0. You have a coil with key on power and a ground side driver. A module, in this case the PCM, breaks the ground to the primary windings to collapse an EM field inducing a high-voltage charge in the secondary windings, and then that charge then goes out to the plug electrode and then jumps the gap to ground in the block.

The only difference between COP and a traditional distributor is that the coil is constantly attached to one cylinder, so it can be fired multiple times into the same cylinder, regardless of engine position. It effective the manufacturer to give every vehicle factory MSD.

You can get the same thing with EDIS (coil packs) but the COP system doesn't have paired cylinders, so you aren't needlessly firing half your spark plugs on every rotation, so they last longer.


The coil hold-down bolt is just that, it holds the coil down, and shouldn't ever be a path to ground.