where does high voltage go after jumping gap

I have just been watching how do magnetos work on youtube .. can someone explain what happens to the high voltage after it has jumped spark plug gap.. thanks in advance
 
(quoted from post at 20:10:46 08/20/16) I have just been watching how do magnetos work on youtube .. can someone explain what happens to the high voltage after it has jumped spark plug gap.. thanks in advance

Where did the pressure go when water leaves the tap?
 
And did you know the spark polarity outputted by a typical magneto alternates between positive and negative as each successive cylinder fires?
 
Sorry, this may be too much theory for non sparkies, but as an old engineer I just cant help myself lol

When the coils LV Primary current is interrupted when the points break open and the magnetic field collapses, voltage across the HV Secondary rises only high enough until current arc jumps across the plug gap AFTER WHICH IT RETURNS TO ZERO.

When the coil is conducting current caused by the rotors magnet passing by it (electromagnetic induction) energy gets stored via the surrounding magnetic field...........When coil current stops (points open) that stored energy gets dissipated due to the rising HV causing current to arc jump the plug gap, and then all the energy being used up there's no more voltage across the secondary until the process repeats itself. The rotor magnets North then South poles alternately passing by the coil causes opposite polarity sparks each time.

Got it????

John T
 
(quoted from post at 20:10:46 08/20/16) I have just been watching how do magnetos work on youtube .. can someone explain what happens to the high voltage after it has jumped spark plug gap.. thanks in advance
fter jumping the gap, the current keeps on going, thru the base of plug, head, etc., and ultimately completing the loop thru the winding where it originated. Just like the power company's electric current.....they sen it out on one wire , get it back on the other and charge you for pushing it out & back! :twisted:
 
(quoted from post at 03:27:47 08/21/16) And did you know the spark polarity outputted by a typical magneto alternates between positive and negative as each successive cylinder fires?

That is not good; reverse polarity will need 40% more energy to jump the gap. From what I've read, it's backward when the spark jumps from the ground electrode to the center electrode on the spark plug. The ground electrode is hotter than the center, and it takes more energy to jump off the hotter side. If you had a weak magneto, almost fouled plugs, the engine would miss every other firing.

From your use of 'typical magneto', somebody makes one that doesn't reverse; an I right?
 
(quoted from post at 12:55:10 08/25/16)
(quoted from post at 03:27:47 08/21/16) And did you know the spark polarity outputted by a typical magneto alternates between positive and negative as each successive cylinder fires?

That is not good; reverse polarity will need 40% more energy to jump the gap. From what I've read, it's backward when the spark jumps from the ground electrode to the center electrode on the spark plug. The ground electrode is hotter than the center, and it takes more energy to jump off the hotter side. If you had a weak magneto, almost fouled plugs, the engine would miss every other firing.

From your use of 'typical magneto', somebody makes one that doesn't reverse; an I right?
on't let it keep you up at night..........some modern electronic spark engines fire both neg & pos..........they all work just fine. that 40% number keeps growing every time I see it. :wink:
 
AFAIK, all commonly-produced and sold HT mags "back in the day"
using a rotating magnet fired that way because they fire twice for every revolution of the magnet.

Exceptions would be (typically older) mags with external/horseshoe/stationary magnets, including oscillating magnetos.
 
Some 4 cylinder magnetos fire positive on all 4 spark plugs but some magnetos fire one plug positive and the next plug negative then positive again, so on. The same plug will always fire the same. Once the points open the current stops in the primary windings and the collapse of the magnetic field induces a voltage in the highvoltage windings causing it to jump the gap on the plug. Once this happens there is no current flowing again until the points close. It's quite simple.
 
From the early days until near modern times, Harley's fires one plug positive and the other negative.
 
It goes off into the atmosphere, and bounces around until there is enough built up then THOR throws it back to the earth in the form of lightning bolts during thunderstorms.
 
Doesn't it just change into energy which produces work. It does not cease to be just changed. But electricity has always been a mystery to me.
 
(quoted from post at 13:22:48 08/26/16) Doesn't it just change into energy which produces work. It does not cease to be just changed. But electricity has always been a mystery to me.
uch of it went into the heat that is the "match" that lit off the petrol fire.
 
Do you ever wonder where your red car's color goes when you turn off the light in your garage? Of course not! The color is just a property your car has when light shines on it. It doesn't "go" when you turn off the light because it was never "there" to begin with!

Likewise, voltage is an electrical property. It's not a "thing" that "comes" and "goes". At the instant before the spark crosses the spark plug gap, there is voltage on the electrode relative to ground. After the spark crosses the gap, the voltage goes to more or less zero, not because it "went", but because the coil energy that caused it has been dissipated in the spark gap.

So the "thing" in this case is energy, which gets converted from mechanical energy to electrical energy in the magneto, and from electrical energy to thermal energy in the spark gap. And so the energy didn't "go" either, it was just converted from one form to another.
 
(quoted from post at 13:47:42 08/22/16)
(quoted from post at 20:10:46 08/20/16) I have just been watching how do magnetos work on youtube .. can someone explain what happens to the high voltage after it has jumped spark plug gap.. thanks in advance
fter jumping the gap, the current keeps on going, thru the base of plug, head, etc., and ultimately completing the loop thru the winding where it originated. Just like the power company's electric current.....they sen it out on one wire , get it back on the other and charge you for pushing it out & back! :twisted:

But only after directing it through those wind turbines. Seems as if the power company gets back more than what is sent out, so they have to use up some of it. Somewhere. Powering a turbine uses up most of the excess. :lol: :roll:
 
I can see that for an 'engine speed' magneto; but is it still true for a half speed? In other words, one with a 2:1 reduction gear in the distributor section?
 
(quoted from post at 11:11:50 08/27/16) I can see that for an 'engine speed' magneto; but is it still true for a half speed? In other words, one with a 2:1 reduction gear in the distributor section?
hile I can't speak for every magneto ever made, those I have held, had the 'generating' portion spin at engine speed and a 2:1 reduction for the spark "distributing" rotor portion. For this kind of design, the answer is yes, every other spark alternates in polarity.
 

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