There is no high voltage "coil wire".

I just appears to be wired in series, or maybe parallel with the main coil?

What is the theory of operation on this?

It can't add to spark, does it affect saturation time in the main coil in some way? How does it accomplish its mission?

Any insight appreciated.

Doug

 

It is wire Pos to Pos, and Neg to Neg.

It was to aid main coil charge time back in the day. The V12 has only got 30deg between trigger points, oops.
Both coils are about 1.2ohms on their own, and 0.6 to 0.8 when paired.
That 1.2ish was the spec of good old standard Contact Points coils.

NOTHING complicated in these cars.

The module inside the Amp is OK up to about 1.0ohms, so when that Aux coil fails, as the do/can, the Module gets fried, and all sorts of things get blamed.

Duceliar introduced a single coils as a replacement, Mega $$, and I never used one.

I used a Fuelmiser CC215 Universal Electronic Ignition Coil on all mine with NO issues at all. Its an OZ company, so no idea for other markets.
Sits at about 0.8ish Primary Ohms, and taht is good enough for me.

 

The coils are wired in parallel, and according to Ohms law that reduces the resistance in half. When the V12 was introduced low resistance coils didn't exist and a high resistance coil can't charge fast enough to provide enough energy for the very short spark interval needed on a 12 cylinder engine.

A low resistance coil can charge faster, and also dissipates less energy as heat. The electronic module is pushed right to the design limit at higher revs, so a fast charging coil is essential.

The dual coil system was a very clever and low cost way to make a low resistance coil when a single unit didn't yet exist.

 

You guys are all talking about resistance and you should be talking about inductance........

 

I was just going to ask about that.

It would seem that a simple 1.2 ohm resistor in parallel with the coil would reduce coil ohms much cheaper.

But a resistor has no inductance.

Now, I am NOT an EE (by any means, they didn't teach electrical stuff in ChE classes), but i am assuming that for this two coil method to work, both resistances and inductance's must be equal?

Doug

 

Ignition coil Theory of Operation

From Kirby Palm book......

The Lucas CEI system uses two conventional ignition coils wired in parallel. The high-tension lead of the
secondary coil is sealed off, and only the lead from the main coil is connected to the distributor. Between firings, energy
is built up in both coils. When the 12V supply is broken (“the points open” in the lingo of the pre-electronic age), the
energy stored in the secondary coil cannot escape through the high tension lead because it is sealed off, so the energy
comes back through the 12V leads instead. The primary coil then not only has to release the energy it has stored itself,
but also the energy coming back from the secondary coil. These two energies add to produce a powerful output at the
high tension lead on the primary coil.
The secondary coil, located in front of the radiator, is not a spare or a backup; it is designed into the system for
producing a good spark. If the secondary coil goes bad or gets disconnected, the performance will suffer; typically, the
engine will top out at around 4500 RPM and won’t go any faster. The secondary coil is not special, however, and can
be replaced with a conventional coil provided the high tension connection is covered so that it cannot arc to ground.

 

What keeps the 'energy", which has to be either higher amps or volts, or a combo of the two, from going back past coil #1 and frying other electrical stuff in the system? I suspect that answer from the book isn't exactly correct.

Doug

 

Because at that point it's not between bat +ve and ground, it's between bat +ve and both coil -ve terminals which are isolated from ground (chassis) because the connection to ground is open.
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I just knew there had to be a complicated simple answer that nobody would really understand, and I believe you all just proved it LOL!

Jack