I made a calculator

[Dampmaskin]

Wire length is longer for the clapton because the resulting wire is thicker. That makes the actual diameter greater despite the inner diameter being identical, and since the length of the wire is (rougly) diameter times pi, the length of the wire is greater.

That is why you get a higher resistance with claptons. The reduced resistivity per unit of length due to the wrap being in parallel with the core, is not enough to counteract that.

 

[100%VG]

Wire length is longer for the clapton because the resulting wire is thicker. That makes the actual diameter greater despite the inner diameter being identical, and since the length of the wire is (rougly) diameter times pi, the length of the wire is greater.

That is why you get a higher resistance with claptons. The reduced resistivity per unit of length due to the wrap being in parallel with the core, is not enough to counteract that.

Just saw this.

Basic Electricity teaches that any time two or more resistances are in parallel, RT will always be lower than the lowest resistance in the parallel group. A 2MΩ and a 1MΩ in parallel with a 10.0Ω will be less than 10.0Ω. It is 9.998500225Ω, to be very close to exact. Maybe 9.9985Ω is not less than 10.0Ω by much, but RT will be lower.

When the values aren't Megohms higher than the lowest, the difference in RT below the lowest is greater.
When 5.0Ω is in parallel with 10.0Ω and 15.0Ω, RT = 2.7273Ω . . . nearly half of 5.0Ω.

So how can a Clapton Coil be any different? Not trying to be argumentative. Just trying to understand.

A fatter wire gauge has less Ω/inch than a thinner one. This is a large reason why a huge wire gauge is used in Electrical Transmission lines, and why thousands of Volts are used as well. This is done to lower I²R losses.

28g Kanthal has less Ω/inch than 32g does. So how does a fatter resulting Clapton Coil have more Ω/inch?

Thanks

PS:
Unless all you are talking about is the length of the smaller gauge wrapped wire.

.

 

[Train2]

Hey, I never realized that the creator of Steam Engine hung out here on ECF.
AWESOME set of tools - THANK YOU.

I also never really looked at the liquid calculator before, and though I realize you're doing a lot of work on the Wire Wiz, I wanted to throw out a simple suggestion.
Most people I know think of their target nic strength in terms of "mg/ml".
As in, they make 6mg juice. And they mean mg/ml.
Your calculator asks for target nic as a %, and I think new mixers might get confused, or make an error by a factor of ten - putting 6 in that field. I'd suggest offering a choice perhaps: EITHER a target %, or a target "strength in mg/ml"...or switch it to mg/ml.

Again - great resource, I use the coil calculator regularly.

 

[mackman]

You can change the value under Nicotine unit to mg/ml

 

[Dampmaskin]

So how can a Clapton Coil be any different? Not trying to be argumentative. Just trying to understand.

It's not. Look at the screenshots you posted. Resistivity for the single wire is 5.36 Ohm/m. Resistivity for the Clapton is 5.31 Ohm/m.

The reason why the Clapton has higher resistance, is because it is a significantly longer wire.

It is a longer wire because it is a thicker wire. To wrap a thick wire 6.5 times around a certain diameter, you need a longer wire to achieve that, than you would if you were using a thinner wire. This is because the circumference of the coil is the (not inner) coil diameter times pi. The thicker the wire, the greater the diameter.

There is one step in the calculation that can be argued about: I originally used the neutral axis diameter of the coil (inner diameter of coil + wire diameter) * pi to calculate the length of each wrap, but that turned out low. I am not 100% sure why, but I suspect it has to do with the metal stretching while it's being bent around a screwdriver, making the wire longer and thinner than it was. In order to achieve a higher accuracy at the cost of mathematical cleanliness, I decided to use the outer diameter, the (inner diameter of coil + (wire diameter * 2)) * pi, instead of the neutral axis times pi. This has turned out to be more consistent with the results people have actually been getting, so I've decided to stick with that.

So in a Clapton, the Wire Wizard calculates the length of a wrap roughly like this:

((the diameter of the core) + ((the diameter of the wrap) * 2)) * pi

While a single coil is just

(the diameter of the core) * pi

The Clapton core and wrap are in parallel, but the wrap has much higher resistance than the core, so it does very little to lower the total resistance. In order to get a better overview of the factors that come into play, I suggest you check the "Show results for all components" checkbox at the upper right of the window, directly beneath the "Celsius/Fahrenheit" selector. That will give you a results box for each individual component of your coil.

 

[Train2]

Oh, geez - just missed that completely. All good, thanks!

You can change the value under Nicotine unit to mg/ml

 

[WileE]

Wire length is longer for the clapton because the resulting wire is thicker. That makes the actual diameter greater despite the inner diameter being identical, and since the length of the wire is (rougly) diameter times pi, the length of the wire is greater.

That is why you get a higher resistance with claptons. The reduced resistivity per unit of length due to the wrap being in parallel with the core, is not enough to counteract that.

We are completely on the same page with your above statement. I'm not questioning that compensation.
Before Wire Wizard was released I used to account for the increased diameter due to the wrap wire by adding 2 x the wrap wire diameter to the ID of the core wire on the normal coil calculator tab. That is how/why I noticed this issue.
I actually noticed the std coil tab was doing a better job of predicting Ω on my Claptons & that is why I'm persisting.

The reason why the Clapton has higher resistance, is because it is a significantly longer wire.

The issue I'm questioning is that I think there is an error in the code causing the Clapton core wire to be calculated significantly longer then it should be. The issue seems to proportionally worse, the larger the wrap wire is. I suspect that the wrap wire diameter used to adjust the coil diameter is being multiplied by 4 instead of 2.

I will try to demonstrate what I'm seeing with several more screen shots.

First just baseline of single wire. It matches up well between std coil tab & Wire Wizard.

1B 28/34 Clapton with core wire compensation on std coil tab

2B Same build as 1B done on Wire Wizard with higher ohm predicted for Clapton then std coil tab predicts for the Core wire by itself?? Actual build ohm closely matched std coil tab prediction.

3B Core wire over compensated to match Wire Wizard

1C Std coil tab with primary/core wire id compensation for 1.5mm coil id 26/30 ga Clapton

2C Wire Wizard 26/30 Clapton & deviation comparison.

 

[100%VG]

It's not. Look at the screenshots you posted. Resistivity for the single wire is 5.36 Ohm/m. Resistivity for the Clapton is 5.31 Ohm/m.

The reason why the Clapton has higher resistance, is because it is a significantly longer wire.

It is a longer wire because it is a thicker wire. To wrap a thick wire 6.5 times around a certain diameter, you need a longer wire to achieve that, than you would if you were using a thinner wire. This is because the circumference of the coil is the (not inner) coil diameter times pi. The thicker the wire, the greater the diameter.

There is one step in the calculation that can be argued about: I originally used the neutral axis diameter of the coil (inner diameter of coil + wire diameter) * pi to calculate the length of each wrap, but that turned out low. I am not 100% sure why, but I suspect it has to do with the metal stretching while it's being bent around a screwdriver, making the wire longer and thinner than it was. In order to achieve a higher accuracy at the cost of mathematical cleanliness, I decided to use the outer diameter, the (inner diameter of coil + (wire diameter * 2)) * pi, instead of the neutral axis times pi. This has turned out to be more consistent with the results people have actually been getting, so I've decided to stick with that.

So in a Clapton, the Wire Wizard calculates the length of a wrap roughly like this:

((the diameter of the core) + ((the diameter of the wrap) * 2)) * pi

While a single coil is just

(the diameter of the core) * pi

The Clapton core and wrap are in parallel, but the wrap has much higher resistance than the core, so it does very little to lower the total resistance. In order to get a better overview of the factors that come into play, I suggest you check the "Show results for all components" checkbox at the upper right of the window, directly beneath the "Celsius/Fahrenheit" selector. That will give you a results box for each individual component of your coil.

Thanks for the clarification!

I don't have a problem understanding the rest of it.

Thought:
Maybe using the neutral axis diameter of the coil was not accurate because a Clapton wire is not a Solid wire, like 22g Kanthal is. It is filled with air gaps from the round wire wrapped around the core wire. Even the outer circumference is not solid, but rippled. And bending the Clapton around to make a Coil with a particular inner diameter makes the outer circumference even more gapped, along with whatever stretching happens. The wrapped wire may be stretched some in the wrapping process of making the Clapton, but it is stretched even more in the Coil wrapping process. So it looks like two factors come into play with your calculation's accuracy when using the neutral axis diameter of the coil.

There may also be errors between various users caused by imperfect spacing of the wrapped wire. The wrapped wire would be hard to get perfectly wrapped and touching one wrap to the next throughout the entire Clapton. The inner core wire might also become twisted, and that could change its standard Ohms per specified distance, too.

Also, an imperfectly wrapped outer wire (with spaces between wraps) will change the length of wire used to be less.

I'm glad you found a way to make it better.
.

 

[WileE]

Well I'm Glad it's all clear for 100%VG, however my last post has not been addressed?? I love the Steam Engine calculators, but there is definitely an error in the formula affecting the wire length for the Claptons. The error results in 12% -20% to high resistance prediction. The resistance calculation is correct, but is predicated on an inaccurate wire length due to???

 

[100%VG]

@Dampmaskin

Hi,

I have a question about the Silver and Gold that needs to be used in the Coil Calculator and Wire Wizard.

Are these calculations made with 24K Yellow Gold (100% Pure Gold)? If not, then what, please?

What purity of Silver should be used to match the Coil Calculator and Wire Wizard?

I am assuming that alloys should be avoided, as much as possible.

Thanks!
.