Ignition Coil Polarity Test?

[Turbo98]

I will be doing some testing with a plasma ignition system on my car. The car has a waste spark system and thus has coil packs. The individual coils within the coil packs basically fire the two plugs at the same time in series. Is there an easy way to test the polarity of the coil terminals--maybe by simply using a voltmeter?
Thanks.

[CosmicFarmer]

Ignition coils (as far as I know) share a common - end and the high voltage + end is where you usually get your spark from.

You can try here
Electric Transformers: Transformers Testing - Polarity Test

or here for flybacks
Testing of Flyback (LOPT) Transformers


Observe the dotted line box

[Turbo98]

Well, it's both the high voltage outputs of the waste spark coil that I need to check. I came across this for a conventional coil and am curious if this type of test would work to determine the polarity. Most coils fire on forward polarity (negative to positive) but with the waste spark system, the two plugs are fired in series with the coil so one plug fires on forward polarity and the other on reverse polarity. Here's the procedure for a conventional type coil:

"Set a voltmeter on the highest volt range (these connections are the same whether you have a positive ground or negative ground electrical system). The secondary winding's polarity, which you are testing, is determined by the combined hookup of the battery and primary windings.

Crank the engine over (do not start it) and the needle of the voltmeter should show an upward swing to the plus or positive side (do not worry about taking a reading). If volt meterthe needle swings down to the negative side and gives a negative reading, your coil is hooked up backwards. To correct the polarity, simply reverse coil primary leads."

So would this type of principle work for the waste spark coil? If I hook up the negative lead from the meter to the negative HV terminal and the positive lead to the engine ground and crank the engine, would the meter jump to positive?
Thanks.

Thanks.

[Turbo98]

Anybody?
Thanks.

[Jetijs]

Take a HV diode or make one yourself using a string of 1000v diodes. Put it in series with the HV output and see if the spark will jump across the spark plug. If you connect the diode in series just as in the upper example in the picture above and there will not be any spark, then it means the your HV output is of negative polarity. If there will be a spark, then your HV output is of a positive polarity. It is as simple as that.

[Turbo98]

Great. Thanks. I'll try that. I do have an HV diode so I'll use that.
I'll report back how it went.

[Turbo98]

Also, from what you're saying if the bottom circuit fires, the HV coil terminal would be of negative polarity? This would be a way ov double checking it then. Thanks again.

[Jetijs]

Yes, the bottom part of the picture verifies that the HV polarity is indeed negative.

[Turbo98]

Cool. Thanks.

[TRON]

polarity check

use a graphite (real graphite) pencil, like a construction pencil with lots of wood and a thick lead. Place it between ground and the wire off the coil on a known polarity coil. then observer if the spark jumps between the lead tip and ground or the lead tip and wire, a negative polarity will jump one gap a positive polarity will jump the other gap.

[Turbo98]

Yes, the bottom part of the picture verifies that the HV polarity is indeed negative.

One othe rthing. We would need to either ground the other terminal of the coil (the other terminal tha the diode isn't connected to) or connect the spark plug ground directly to the other coil terminal to complete the circuit, correct? This is a waste spark coil pack so it isn't typicaly grounded. Which way would be better for this test?

[Jetijs]

One othe rthing. We would need to either ground the other terminal of the coil (the other terminal tha the diode isn't connected to) or connect the spark plug ground directly to the other coil terminal to complete the circuit, correct?

Correct.
In usual car ignition coils the other HV coil lead is already grounded (connected to the negative of the primary coil) thus also the spark plug ground is connected to the same negative terminal of the ignition coil via the car body.
I don't know what a waste spark coil pack is.