A coil question-serial dual coils.

[conanthewarrior]

Hello everyone.

I have a question that has puzzled me for a long time-serial dual coils.

Now, as we know, when we make a standard dual coil setup, the resistance is halved.

To keep it simple, I will use a 3 post example.

If you use one length of wire, this does not happen, and the resistance increases and it not halved-but, when you screw down the positive post, you are essentially bridging the two wires together, so I don't see exactly HOW the snip is noticed?

Someone with more knowledge will be able to explain this I know, but it really perplexes me that cutting the wire, halves the resistance, while keeping it together, wrapping a continuos length of wire increases resistance( I know wire length increases resistance, but I just don't get how the split is noticed in a 3 post deck), especially on a 3 post deck, as the wires are generally right next to each other-similar to how you would splice a wire, just without the twist.

Thanks everyone, Conan.

 

[Mr Numpty]

Hmm, that does seem a little odd now you mention it. I'll also be interested in the answer.

 

[oldhippydude]

A wire is like a hose for electricity and a longer hose has more resistance to flow.
Dual coils are like two shorter hoses, similar to one short hose with twice the volume so the resistance is half.
Think of the center post (+) as the tap with a fixed water pressure.

 

[Crewella]

A wire is like a hose for electricity and a longer hose has more resistance to flow.
Dual coils are like two shorter hoses, similar to one short hose with twice the volume so the resistance is half.
Think of the center post (+) as the tap with a fixed water pressure.

That's brilliant, thank you.

 

[Mr Numpty]

But the question is why, if both coil's ends are touching at the positive post of a 3 post deck, does it not see the wire act like 2 coils wound from a single piece of wire? After all, the cut wire coils should form a continuous electrical connection by virtue of their ends touching, in much the same way as an uncut wire.

 

[ned]

i tend to keep it single stupid.

 

[drlnhs]

Conan are you referring to the "sleeper coil" I.e dual coils wrapped from a single piece of wire? If so your resistance should actually be slightly lower than the equivalent dual coils because there is no break in the current flow. This is why a sleeper coil will heat quicker and more evenly than a pair of dual coils and the more direct and uninterrupted the current flow the lower the resistance will be. Personally I prefer single coils but with exotic wire and smaller post holes the sleeper coil is useful for ease of build purposes

 

[oldhippydude]

But the question is why, if both coil's ends are touching at the positive post of a 3 post deck, does it not see the wire act like 2 coils wound from a single piece of wire? After all, the cut wire coils should form a continuous electrical connection by virtue of their ends touching, in much the same way as an uncut wire.

Surely it does.
I sometimes build both coils with the same bit of uncut wire or two bits of wire.
Same thing. I am fairly sure I am right (ish) about the question I am answering.
Quite willing to accept I may not understand the question being asked.

 

[Mr Numpty]

Surely it does.
I sometimes build both coils with the same bit of uncut wire or two bits of wire.
Same thing. I am fairly sure I am right (ish) about the question I am answering.
Quite willing to accept I may not understand the question being asked.

No, you're right. I think I was thrown off by @scrumpox's dual coils from a single wire in the Aromamizer being twice the resistance as two separate coils but realise now that that's because they are only utilising two posts. I thought the same principle held for three post builds but I see now that they don't so all is right with the world again. Sorry for the confusion, which was all mine.

 

[Tubbyengineer]

But the question is why, if both coil's ends are touching at the positive post of a 3 post deck, does it not see the wire act like 2 coils wound from a single piece of wire? After all, the cut wire coils should form a continuous electrical connection by virtue of their ends touching, in much the same way as an uncut wire.

I think the problem here is people tending to assume that the 3 posts are seperate connection points and that current flows from one to two and on to three - they aren't. The centre post is positive and the two outer ones are negative and to all intents and porpose are the same post so what you actually get on a three post atty is two wires stretching from a single postive post to a common negative with multiple connection points