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I recently bought an ignition coil
http://www.thansen.dk/product.asp?c=286 ... 1681984759
a 12 volt scooter battery and a spark plug.
but i cant get the spark plug to light.
can someone draw or explain to me how i have to set it up to work.
i have seen other drawings of how to do it but that was with a different ignition coil
From Esben, Denmark
Those plugs aren't designed for 12 volt primary. I fried one myself trying to get it to work.
well got get a car one then.
thanks for your help.
by the way how would you recommend switching the spark plug on and off. taking the + on and off the battery or something like that?
You might just try it with a 9V battery. Just touch the battery's posts to the two spade plugs on the coil. Stick a piece of wire into the end of the high tension wire and bring it back around near one of the two battery contacts. Rock the battery on the contacts so the electrical contact is made and then broken.
What is that coil for? There isn't much info on the linked page and the only Swedish I know I learned form the Swedish Chef on the Muppets show.
jimmy; my best "edumcated" guess would be the brass colored mounting hole is actually the ground for the HV side, the blue marked tab is the battery +, and the other terminal is battery -. The connection between mounting hole and battery may not be internally connected. These two connections are definitely connected when mounted for it's original application.
I could be wrong, depends on how it was manufactured.
Like you say, I know even less Swedish.
For how to use it, infomation on kettering ignition see, http://en.wikipedia.org/wiki/Ignition_system
Transformers are not compatible with DC. To use them a pulse is needed. Either a high voltage pulse from a camera flash is used (call Capacitive Discharge Ignition DCI ) or a current of low voltage is allowed to build in the inductive windings and a high voltage pulse is generated when the current is suddenly interrupted. To properly form the pulse a capacitor is needed in addition to the points (Switch).
Even though the low voltage side is fed low voltage DC a high voltage spike is created when the switch is opened. Don't get your finger on it because it is very unpleasant.
Leaving DC connected to the coil will burn it out if a current limiting resistor is not used.
Dang Technician, you beat me too it. But anyways he's right a driver is needed to turn that 12VDC into 12VAC. You will need a signal generator and need that feeding into a gate that is attached to the main. Or you can make a rotary spark gap, that works too
Roatary spark gap.. 12 volts..
They are better suited for Tesla coils at 5KV primary.
A coiler recommended this.. I'm ashamed.
Disclaimer.. I have built a Tesla coil.
For a single spark, a single momentary contact doorbell button works fine.
A quick push and release does the trick. It's all the signal generator needed.
Hey I have done 12VDC primary into a 48000Hz rotary spark gap before. I put that into a 10x step up transformer to make a 120V 48kHz signal before. It worked like a charm!
Tech, I realize all your info about ignition system schematics.
I was involved with ignition systems before you were even born.
Now you really know my age!
The capacitor ( condenser back then) across the points was to reduce the arc across the points so they would last longer. Keeps them from being pitted. It would still function without it.
The capacitor is used to absorb the back EMF from the magnetic field in the coil to minimize point contact burning and maximize point life.
Most auto ignition HV coils are "autotransformers". That means they are three wire devices and the primary and secondary coils share a connection. You hook up voltage to the two primary connections. The HV connection (the one with the big fat cable) is one side of the secondary. The other side of the secondary is one of the two lugs on the primary.
I would guess the copper pipe looking thing in the mounting hole is just so you don't collapse the bracket with the mounting bolt. But it could be the other HV lead. So, see if the HV lead sparks to it as well as to the two spade lugs.
You don't necessarily need a signal generator. An ignition transformer will usually give a decent spark if you just hook it up to a voltage source (on the primary), wait a moment then disconnect the source. That's all that a set of mechanical points does, though the points do it repeatedly.
You should be able to just wire a pushbutton switch in series with a battery and the coil. Push the button. When you release the button you should get a spark.
The "condenser" in the old style auto ignition circuit actually does a couple things. Besides protecting the points from the coil's back EMF it also contributes to the pulse shape. If you omit the cap the pulse shape isn't as nice and the spark energy decreases.
EDIT: "repeatedly" not "respectively"
Last edited by jimmy101 on Thu Jun 11, 2009 5:14 pm, edited 1 time in total.
Having a full career in electronics, there is something that simplistic explanation is missing. Since the discussion is technical, I'll fill you in.
The condenser is to delay the rise of the voltage on the points so the points can open with little arcing so the EMF of the collapsing field in the coil isn't wasted in an arc at the points. The value of the condensor is selected so the metal transfer at point opening is matched to the metal transfer of the condenser discharge when the points close. Too big causes metal transfer and too small causes metal transfer the other way. The LC time constant determines the rise time of the peak until flash over in the plug. The shorter the rise time the higher the voltage. A small cap is highly likely to have the flash over on the points drawing an arc while a large cap is likely to lower the voltage to the point of misfire. A happy medium is in the middle.
Unless you are a WWII vet, I have my doubts on your age in relation to mine.
Since you are picking on my age, Go back a few more years before plugs when Ignitors were used. They are much like an ignition coil, but without the secondary. Used without a condenser, the points draw an arc when they open. These mechanical points were placed inside the combustion chamber and driven off a cam like the valves. Yes I have seen them. References gladly
Igniters can be used on a spud gun if anyone is interested.
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