Your Basic Coil

[shylo]

Hi WTM,
I'm just a tinkerer so not any help, are you charging the cap bank ,then disconnecting it from batteries, and then attaching the led's to discharge the bank , and then repeating?
A circuit diagram and video would help to clear the air.
But the idea of a few days of work being done ,and voltages rising is very interesting to me.
Hope you post.
Thanks artv

[wantomake]

testing trifilar coil

Ive been learning while testing with trifilar coil setup as LC tank with cap bank, led light with resister as load, and two 9 volt batteries. All in series.

I started by charging the cap bank up as much as it will. About 2 volts below battery bank amount. The led lights brightly then slowly diminish to off.

The interesting part is when a load is placed across the cap bank to discharge it the LED lights very bright. Then remove the load from cap bank, the battery voltage drops then starts to build up to original starting voltage. At same time the cap bank (5F 2.7 v x 7) starts charging up also.
Over an a period of 2-3 hours the LED deminish in brightness then turns off when both battery bank and cap bank returns to starting voltage. Over period of days both charge by tenths of volts to higher amounts.

I do need to post a schematic and video, which I will if this is important.

So is this normal for a trifilar coil???

It seems this circuit in series would discharge a power source with any type load connected to it. As a LC tank would.

Please be nice I'm just a student here.
Thanks,
wantomake

[gotoluc]

Deleted

Thank you.

Deleted

Thank you.

Deleted

Thank you.

Deleted

Thank you.

Deleted

Thank you.

Deleted

Thank you.

Deleted

Thank you.

Deleted

Thank you.

Deleted

Thank you.

Deleted

Thank you.

No need, I'm out.

Yes... and erasing all your posts with it

I wonder why

Some things are mysteries though I have seen this pattern before

Luc

[BroMikey]

Hi BroMikey,

Just out of curiosity, I have built a single layer, air cored bifilar coil from enamelled copper wires putting them side by side (no twist) on a 3 cm OD paper bobbin, wire length was 2 x 210 cm from wire OD=1 mm (AWG 18), it gave 21 turns. See attached picture 1. .....................

Gyula

Thank you that answers my question, great teaching for simple
step by step understanding of coils and their possible variations.

[gyula]

In your studies with the Bifilar coils inductance did you also slightly
twist the 2 bifilar conductors like we were instructed with the SSG?
I would be interested to know if your measurements
(if you did that experiment) showed more or less inductance
for twisted bifilar vs just putting conductor side by side without
twisting them.
....

Hi BroMikey,

Well, I mostly twisted the wires for building transmission line transformers back then and never compared inductances with bifilar coils where the wires were guided side by side without any twist.

Just out of curiosity, I have built a single layer, air cored bifilar coil from enamelled copper wires putting them side by side (no twist) on a 3 cm OD paper bobbin, wire length was 2 x 210 cm from wire OD=1 mm (AWG 18), it gave 21 turns. See attached picture 1.
Measured inductance between Start 1 and End 1 is 8 uH and also 8 uH between Start 2 and End 2.
Measured inductance between Start 1 and End 2 (the two windings were connected in series aiding phase) was 30 uH.
The ratio is 30 uH/8 uH= 3.75 this is close to 4.
Measured capacitance is 270 pF between either Sart 1 and Start 2 or between End 1 and End 2, (the not being measured wires were freely floating, of course).

Then I unwound this coil and twisted the same two wires, roughly by 2 twists per inch and rewound it onto the same bobbin, to have 21 turns again. See attached picture 2.
The measured capacitance was only 230 pF between Start 1 and Start 2 or between End 1 and End 2. But this smaller capacitance versus the above case stands to reason because the angled wires could not have as many facing surfaces as they had in the side by side, very close guided to each other case.
The received inductance between Start 1 and End 1 was again 8 uH as was also between Start 2 and End 2. Likewise, the measured inductance was 30 uH between Start 1 and End 2 (winding were in series aiding phase).

IF somebody has confusion what a bifilarly wound coil connected in series aiding phase means, well it means that the end of the first wire is connected to the start of the second wire if you label the starts of the two parallel guided wires as start 1 and 2 and you label the ends of the two wires as end 1 and end 2. This means also that you have to prepare in advance two wires of appropiate length from two different rolls and always guide them in parallel while making the bifilar coil. (Of course you can cut twice the needed length of wire from one wire roll too and then guide the wires also in parallel while winding.)

The series aiding phase connection is the same you show in the above picture.

So the answer to your question is that with this single layer air core bifilar coil there is no difference in inductance between a twisted and the side by side guided (not twisted) winding styles. IT is possible that for a multilayer bifilar coil the twisting introduces some change in inductance because the capacitance between the twisted wires will be different from that of the side by side wires. The capacitance between the two wires is transformed in parallel with the bifilar coil so it has the tendency of reducing the overall inductance. Notice also that using ferromagnetic cores the capacitance also changes between the two bifilar wires (usually it increases the capacitance between the two wires).

Further measurements on my bifilar coil:

1) Start 1 and Start 2 are connected together and End 1 and End 2 are also connected together: inductance was 9 uH i.e the same as any one of the individual windings. Such connection reduces copper loss only, as if you had used thicker wire for the coil.

2) Start 1 and Start 2 are connected together, the inductance between End 1 and End 2 was less than 1 uH (resolution limit of my L meter cannot let it see more precisely). This connection represents a non inductive bifilar winding shown in the wiki link.

Regarding the counter-wound measurements you refer to in the wiki link, I believe in that case one winding is wound say in clockwise the other is in counter closckwise direction, I did not make such windings.
Here is a good explanation for two mutually coupled coils which can help estimating the answers:
Mutual Inductance of Two Adjacent Inductive Coils

Gyula

[BroMikey]

Hi wantomake,

I am afraid you will not find such specific software. The reason is that due to the close magnetic coupling a trifilar coil has 9 times the inductance because the number of turns is 3 times as many than in the "singlefilar" case. Of course here I assume you connect the three windings in series aiding phase, (the same current flows in them in the same direction). Similarly, a bifilar coil has 4 times the inductance when the two constituting windings are in close magnetic coupling and connected in series aiding phase.
These results also come from the normal inductance formula in which you can find the L inductance depends quadratically on the number of turns. I tested this in practice (years ago) and found indeed that for a bifilar coil the series aiding connection of the two windings resulted in 3.8 times higher inductance compared to the inductance of any one of the two windings. The small discrepency (3.8 vs the theoretical 4) may come from the not 100% perfect magnetic coupling and from a small increase in the self capacitance of the bifilar arrangement (capacitive reactance reduces inductive one).

I find this coil calculator also good and versatile and free

http://coil32.net/multi-layer-coil.html

Gyula

Hello Gyula

In your studies with the Bifilar coils inductance maybe you also slightly
twist the 2 bifilar conductors like we were instructed with the SSG?
I would be interested to know if measurements
(if you did that experiment) show more or less inductance
for twisted bifilar vs just putting conductor side by side without
twisting them.
This reference takes away some confusion on which winding
pattern you suggest.

https://en.wikipedia.org/wiki/Bifilar_coil

Bifilar coil configurations

parallel-wound, series connected
parallel-wound, parallel connected
counter-wound (series)
counter-wound (parallel)





Depending on which arrangement selected seems like a new
value of self inductance and self capacitance is reached but
I have never done these tests.


Thank you in advance.

[gyula]

Does anyone know a website for calculation of a trifilar coil to find induction? This website shows how to find induction of a single or multilayer wound coil.


Coil Inductance Calculator - 66pacific.com

If any help would be great.
wantomake

Hi wantomake,

I am afraid you will not find such specific software. The reason is that due to the close magnetic coupling a trifilar coil has 9 times the inductance because the number of turns is 3 times as many than in the "singlefilar" case. Of course here I assume you connect the three windings in series aiding phase, (the same current flows in them in the same direction). Similarly, a bifilar coil has 4 times the inductance when the two constituting windings are in close magnetic coupling and connected in series aiding phase.
These results also come from the normal inductance formula in which you can find the L inductance depends quadratically on the number of turns. I tested this in practice (years ago) and found indeed that for a bifilar coil the series aiding connection of the two windings resulted in 3.8 times higher inductance compared to the inductance of any one of the two windings. The small discrepency (3.8 vs the theoretical 4) may come from the not 100% perfect magnetic coupling and from a small increase in the self capacitance of the bifilar arrangement (capacitive reactance reduces inductive one).

I find this coil calculator also good and versatile and free

http://coil32.net/multi-layer-coil.html

Gyula

[wantomake]

hummmmm

Thanks Matt,
I will give it a Google or two.

wantomake

[Matthew Jones]

Does anyone know a website for calculation of a trifilar coil to find induction? This website shows how to find induction of a single or multilayer wound coil.


Coil Inductance Calculator - 66pacific.com

If any help would be great.
wantomake

Good luck, thats pretty much manual math. Look for calculation for an inductor that does multi voltage flyback.

Matt

[wantomake]

trifilar coil calculator

Does anyone know a website for calculation of a trifilar coil to find induction? This website shows how to find induction of a single or multilayer wound coil.


Coil Inductance Calculator - 66pacific.com

If any help would be great.
wantomake

[Allen Burgess]

Aul

@ Allen Burgess

Pre-saturation of a core has a value for certain applications and should always be considered.

However, as I have demonstrated, AUL is not a useful effect and is caused by either one of two conditions; inferior cores material or a high impedance coil at higher then normal generator frequencies (rpm) with its output voltage clamped down many times over.
Important information to note: In the second case (high impedance coil) you can test if you've reached this state. Just increase or lower the frequency (RPM) of your prime mover and if the coil still delivers the same power to your load, then your coil is in this state and wasting power as it's reflecting flux it can't deliver to the load back to the prime mover which is causing AUL.

Understand these effects and stop being fooled.

If someone can achieve AUL with quality cores with a low impedance coil please share as that would be refreshing to observe.

Luc

@Gotoluc,

That's what MarkE and Milehigh maintained the entire time. That confirms Thane's just been on a treadmill with it all the while.

[gotoluc]

Thanks for the videos Luc. They are very interesting. I appreciate your efforts to try and educate us about the importance of the core material.
Carroll

hope I got the translation right!

Nice work Luc.

Magnetize the core wound with metglass ribbon.
Push the rotor and capture the flux in a capacitor in less than 11 mSec.
Design the core and rotor geometry going for least iron loss.
Thanks Luc

Thanks guys,

It's refreshing to get some appreciation.

Here is a video demo to update my recent build which should be fired up today.

https://www.youtube.com/watch?v=O9wh23H5lhE

Luc

[gotoluc]

@Gotoluc,

Have you found time to consider my idea of adding an electro-magnetic coil to the core to regulate saturation? Imagine the effect opening and closing this seperate core coil might have on AUL.

@ Allen Burgess

Pre-saturation of a core has a value for certain applications and should always be considered.

However, as I have demonstrated, AUL is not a useful effect and is caused by either one of two conditions; inferior cores material or a high impedance coil at higher then normal generator frequencies (rpm) with its output voltage clamped down many times over.
Important information to note: In the second case (high impedance coil) you can test if you've reached this state. Just increase or lower the frequency (RPM) of your prime mover and if the coil still delivers the same power to your load, then your coil is in this state and wasting power as it's reflecting flux it can't deliver to the load back to the prime mover which is causing AUL.

Understand these effects and stop being fooled.

If someone can achieve AUL with quality cores with a low impedance coil please share as that would be refreshing to observe.

Luc

[mikrovolt]

Magnetize the core wound with metglass ribbon.
Push the rotor and capture the flux in a capacitor in less than 11 mSec.
Design the core and rotor geometry going for least iron loss.
Thanks Luc

[OrionLightShip]

hope I got the translation right!

Nice work Luc.