............So, what does a coil do, anyway?

(This ain't a joke, so don't just sit there waiting for a punchline to pop up)

 

a coil convert's and boost's electrical energy to your igniton for spark.

 

"stold"? What's stold? Do you mean "stole"???
Daryl
outsideL.A.

 

Hi Jeff,

Your coil is two pieces of wire wound around a center iron core. One of the windings is called the primary and the other is called the secondary. The primary has a few turns of a heavier gage wire and the secondary has many turns of a fine gage wire.

When you turn your ignition switch on, 6V is applied to one side of the primary winding in the coil (12V on newer models) and the other side of the primary winding is connected to the negative battery terminal through the points in your distributor. With the points closed, a current is flowing through the primary coil winding. This current creates a magnetic field in the coil - including the secondary winding. As you crank the engine, the points open when a spark is needed. When the points open, the current through the primary side of the coil is interrupted and falls to zero.

Here's the neat part. As the current goes to zero in the primary winding, the magnetic field in the coil tries to collapse and go to zero. Guess what? When you have a coil of wire in a changing magnetic field you get a voltage and current in the wire. So now a large voltage is produced in your secondary winding since it is sitting in this rapidly changing magnetic field inside the coil. Since the number of windings in the secondary coil is very large, the voltage is very high - on the order of 10,000 to 30,000 volts.

One side of the secondary coil is connected to the negative battery terminal and the other side is connected to the center post on the coil. The center post on the coil goes to the distributor center post, through the rotor, and back out one of the spark plug wires to a spark plug. When the coil secondary gets hit with the collapsing magnetic field inside the coil, the voltage in the secondary coil is high enough to jump the gap in the spark plug and you get ignition in the cylinder.

After a spark cycle is completed, the points close again, the coil primary winding gets charged up, and the magnetic field rises to get ready for the next spark cycle. Interestingly enough, you actually get two sparks per cycle - one when the points open and one when they close again. That's because the voltage in the secondary winding is produced by a changing magnetic field - it doesn't matter if the field is collapsing or rapidly rising.

Here is a link that has more info if you're interested.

Auto Ignition Coil Operation

 

stold is past-tense of stole - as in 'today I stole the truck, but yesterday I stold it' ...........


George, I hafta compliment you on that excellent explanation of how a coil works - I think I actually understand it now. Thanks!

 

MAn, that George knows some stuff

I think we should designate him "Perfesser" I. for one would like to see George put some stuff down on paper a la Mr. Niolon.

In awe of your knowledge

I'm not worthy

HAnds

 

OK - cut it out. You guys realize that each of us knows a few things and doesn't know diddly about a lot of other things. When I ask my questions, you always show me how much you know too.

 

Were off to see the Wizard. The Great Wizard of Oz. Maybe he might know how I can get home.

 

Thanks guys (especially George!) -- this tells me so much more than 2 dictionaries and my "How It Works" book series could muster...