Posted by John T on July 22, 2012 at 07:00:19 from (216.249.82.117):
In Reply to: 6v vs 12v BD posted by leej on July 21, 2012 at 18:45:30:
I dont have a dog in this fight and always just try to get along with EVERYBODY and respect them and expect the same in return and am NOT picking sides, but as an electrical engineer I CAN EXPLAIN (to best of my curent and I believe correct knowledge, still no warranty Im long retired and may be wrong) the firing voltage differences if a coil is wired at the correct polarity versus if not.
Im doing this as a public service to educate and HELP IF I SEE CONFUSION,,,,,,,, NOT FIGHT,,,,,,,NOT CHOOSE SIDES
NOTE IM NOT TALKING HERE ABOUT THE ENGINEERING DESIGN DIFFERENCE IN 6 VERSUS 12 VOLT COILS, I ALREADY THOROUGHLY EXPLAINED THAT SOME TIME BACK .....
IM ONLYYYYYYY GOING TO EXPLAIN WHY THE PLUGS WILL FIRE AT A DIFFERENT VOLTAGE IF THE COIL POLARITY IS REVERSED
Okay, any of you who are familiar with the desing of an electron tube like were used in radios etc years back you will know there is a HEATER under the cathode. The reason is its easier to emit electrons from a hotter (heated cathode) to a relatively cooler (Plate) area.
Soooooo the electron tip on a spark plug is muchhhhhhhhh hotter then the ground strap which has the mass of the engine block to which its heat is extracted. THEREFORE its much easier to emit electrons from the cooler tip to the relatively hotter ground strap ANDDDDDDDDDDDDDDDDD IF THE COIL IS AT THE CORRECT PLAORITY GUESS WHAT THATS THE ELECTRON PATH BUTTTTTTTTTTTT IF THE COIL POLARITY IS REVERSED THE ELECTRONS HAVE TO GO FROM THE COOLER STRAP TO THE HOTTER ELECTRODE TIP WRONGGGGGGGGGGGGGGGG
Some data Ive seen and data the late Duane Larson (Theoretical PHd Physicist) experimented and collected from scope traces of coil firings shows it takes like 3,000 to 4,000 volts less to fire the coil at the correct polarity then if the coil polarity is incorrectly reversed !!!!!
Sure, it will still fire at the wrong polarity but the system is more efficient (less heat losses) and the firing voltage is a few thousand volts less IF THE COIL IS USED AT THE RIGHT POLARITY.
For lay persons let me explain that the voltage it takes to arc jump current across a spark plugs gap is a function of 1) The gap distance and 2) The medium (fuel and compression) in which the arc takes place. A coil is NOT instantly at say 10,000 volts, when the field collapses its HV secondary voltage begins to ramp up n rise but onlyyyyyyyyyyyyy until high enough to arc jump current across the gap and noooooooo more
Okay, I cant explain here in a paragragh what can takes books and years of study to understand so if you are still confused to some research and study. Hopefully this helps lay persons understand why its best to use a coil at the corect polarity and why the firing voltage is less (maybe a few thousand volts) if used correctly .
God Bless yall n best wishes
John T Long retired Electrical Engineer but hey I still remember the basics and remember its easier to emit electrons off a hotter (tip) to a cooler (ground strap) and thats why coil polarity makes a difference
NOTE Im rusty on this and never too old to learn sooooooooooo if anyone has later accurate hard engineering data (not some Billy Bobs uneducated guess or opinion) that shows Im wrong PLEASE ADVISE AND HELP ME AND EVERYONE HERE BY BETTER EXPLAINING THE CORRECT ENGINEERING THEORY !!!!!!!!!!
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