Multi-Filar Coils

While making observations of coil designs that have been used over the centuries, I noticed only those that showed some perceived useful results were kept in the arsenal of the scientists, the rest were either ignored or forgotten. There are two basic types and a 3rd being the combination:

1 Circular – Eg Solenoid, flat spiral,spherical, toroidal, mobius

2 Non-circular – Eg Basket weave, geometric, polyhedral, star forms, mobius

The circular types have 3 basic types  a resultant 4th and the unique 5th type:

1 Rings adding vertically –  Solenoid Coil

2 Rings expanding diametrically  – Flat spiral

3 Rings adding in a circular form – Toroidal

4 Rings adding vertically and/or diametrically and/or circular

a) Conical – differing sizes in both direction

b) Multilayer Solenoid – same sizes vertically + differing sizes diametrically

c) Multilayer Flat Spiral – same coils sizes vertically + adding vertically

d) Toroidal and Poloidal windings mixed sizes vertically + differing sizes diametrically

e) Spherical rotations windings mixed sizes radially + differing sizes diametrically

5 Winding folding into itself, creating a single surface  – all possible geometries – Mobuis

The shapes of coils are one aspect the other is the winding order and direction, thus creating multiple poles, cross coupling inductance, retarding or increasing both the inductance and the capacitance as the design requires, the addition of the mobius windings diversifies the basic options, this is where the art is at in 2012. A good example of combining many geometries and winding types is the:

Magnetic coil(1820 Hans Christian Oersted)

Faraday coil(1831 Micheal Faraday)

Henry coil(1831 Joesph Henry)

Induction coil(1836 Nickolas Callan)

Ruhmkorff coil(1851 Heinrich Ruhmkorff)

Helmholtz coil(1869 Herman von Helmholtz)

Maxwell coil(1873 James Maxwell)

Cook coil(1871 Daniel Cook)

Tesla coil 1/4 wave(1891 Nicola Tesla)

Tesla Flat coil(1890 Nicola Tesla)

Tesla Bifilar coil(1894 Nicola Tesla)

Hubbard coil(1918 Alfred Hubbard)

O’Leary Coil(1920 William O’Leary)

Hendershot coil(1928 Lester Hendershot)

Interceptor coil(1946 John Wiegand)

Tokamak coil(1950 Oleg Lavrentiev)

Stellartator coil(1950 Lyman Spitzer)

Smith coil(1952 Wilber Smith)

Fusor coil(1964 Philo Farnsworth)

Hooper coil(1968 William Hooper)

Rodin coil(1986 Marco Rodin)

Biaxial Poloid coil(1990 Bo Atkinson)

Tetra Helix coil(1991 Bo Atkinson)

Vortex coil(1992 Ken Gailey)

Double Helix coil(TM) (2007 AML)

Not to mention my own explorations in coil geometry with:

Mandela coil(1990 Arto Heino) – Page 55 – Link

Crown coil(1994/2011 Arto Heino) – Link

Infinty coil(1993/2011 Arto Heino) – Link

– and many toroidal/polyhedral mixtures that have been popping up regularly with names like the Star ship coil, Loohan coil, Polish coil,  Big Secret coil, some of these are marvels of artistry and human innovation.

Not to mention the many non inductive windings that are used as resistances. This has been looked at for at least 200 years, Nicola Tesla was one engineer/Scientist who’s original thinking left a legacy of numerous winding geometries he used to design his motors and coils,one of these is his Bifilar design. This design exposed a unique addition to the idea of combining the merits of both coil and capacitor without addition hardware contrivances, the anti-series winding nulls out self-inductance.

Nicola Tesla writes that a standard coil of 1000 turns with a potential of 100 volts across it will have a difference of 0.1 volt between turns.
100/1000 = 0.1
A similar bifilar coil will have a potential of 50 volts between turns.
100/2 = 50
In that the stored energy is a function of the square of the voltages, the ratio of energy in the bifilar to a standard coil will be
50^2/0.1^2 = 2500/0.01 = 250000
Which as stated by Tesla, “the energy stored is 250000 times greater than the standard coil!”

The storage of energy when pulsing a bifilar coil is n amount more than a standard solenoid/flat coil, as Tesla stated and gave you the formula to engineer this type of coil, we should be incorporating this simple idea into many everyday devices. I have drawn a few design methodologies that I hope will spur this well known innovation into more interesting directions.

These are basic bifilar solenoid configuration showing the capacitance between each winding. The windings can be rearranged in a different order to change the amount of induction and capacitance you put into the coil.  The winding below shows what can be done to rearrange the capacitive differential to increase the energy storage.

The graphic table below shows how many different arrangements that can be used with a Quadrifilar coil system, each will give a different result for the inductance, capacitance and its resonant frequency spectrum.

A great science/engineering project or University paper for someone would be to tabulate and analyze  each arrangement,  you might just get your doctorate on this.

The flat coil is a dimension less than the solenoid and a lot easier to redefine into  multi-filar arrangements.

The basic geometries involved in designing coils, transformers and bifilar systems must have a few design rules so the engineering of these items become straight forward and adaptable to the needs of the energy transformations. Here are a few simple systems that can be easily expanded and used creatively.

The cipher I am using here is:

B = Blue              R = Red

U = Upper          L = Lower

N = North           S = South      / is the upper part of the cross

E = East               W = West       \ is the upper part of the cross

The order of the letters is the order from the top to the bottom.

The order of the numbers is from the left to the right.

The first set is based on 2 simple loops. This will give you 8 different forms:

The next is the topology of a single loop of wire which loops on itself, like a bifilar or just a plain solenoid:

As you can see by these configurations, the standard engineering practice used in industry only use a small portion of these geometries. Now if you loop 2 coils as used in transformers you will see industry only apply 1 or 2 of these geometries in 98% of all transformers.

The fusing of  Adams motor and the Tesla bifilar coil was one of the first iterations that showed me the correctness of this approach by its exceptional efficiency.

Incorporating both bifilar and loop transformations as shown previously, you can begin to appreciate the transformations I have below to create a magic square coil, as originally shown on my Artoworld website in 1999.

Old photo from 1999

Most of the original readers of these documents never understood my topology in 1999, even though I built many of these coil constructs as stators for pulsed motors. The current breed of experimenter has less inhibitions to these  geometric forms. The first arrangement is the non-magic numeric sequence, just the same as if you wrap a standard solenoid.


The next diagram is the magic square arrangement, which utilizes the the pairing of the “17” as a magic square paring which translates to the bifilar pairing.

Below is the original stator coil I wound in 1999, it performed well and required high voltage(24v) and low current(0.001 amp).

I hope this small extract from my upcoming book “Talking with the Birds” will be helpful in any research you might be doing. Regards Arto

Here is  Link to a Multifilar Coil Manufacturer, called Custom Wire Technologies Inc. Give them a buzz they might help you, Regards Arto

*** Update***

I have had a request to explain the Tesla/Adams Bifilar setup, here is a diagram that should make it transparent. The consequence of using this way of connecting coils will give you a multitude of possibilities for the experimenter to find interesting combinations ,  have fun regards Arto.

AdamsCoilsb2*** Update 2 *** 03-06-2013

Thanks to Andy I have added one more diagram to help decipher my Magic Square Coil arrangements.


*** Update ***

Added the Spiral coil implementation.

AdamsCoilsd4For the continuation of this blog go to :

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54 Responses to “Multi-Filar Coils”

  1. ansyar Says:

    hi artojh,,

    I will design a bifilar coil using ferrite rod to complete my final project. I need some journal about bifilar coil containing explanations, calculations and equations, benefits, and other detail stuff. Can you help me? is there a pdf file of the bifilar coil that you can share to me?
    thank you.

    Liked by 1 person

  2. artojh Says:

    Hi Ansyar,

    Thanks for asking, I am still working on getting data freely available to everybody for these particular types of coils. I have developed a method to test the differences and benefits to using this type and other types of coils, it is still in the drafting stages in one of my chapters in my book. Here is a run down of some of the tests and procedures that I will use.

    Build units

    Standard Coils 6 types (6)

    1 Air core solenoid
    2 Air core Pancake
    3 Ferrite Core Solenoid
    4 Ferrite Core Pancake
    5 Air Core Toroid
    6 Ferrite care Toroid

    Non standard Coil Geometries (6+6=12)

    1 Poloid
    2 Infinity
    3 Tesla Crown

    Each standard/Non-standard coil will have each wound in: (10*12=120)

    1 Unifilar Start-End
    2 Bifilar Start-End-Start-End Connected as per Tesla Bifilar
    3 Trifilar S-E-S-E-S-E
    4 Quadfilar S-E-S-E-S-E-S-E

    5 Bi start-End-End-Start Connected as Low Inductance
    6 Tri S-E-E-S-S-E
    7 Quad S-E-E-S-S-E-E-S

    8 Bi Start+Start-End+End Connected as Parallel
    9 Tri S+S-E+E-S+S-E+E Connected as a Parallel Bifilar
    10 Quad S+S-E+E-S+S-E+E-S+S-E+E

    All the coils will maintain the basic parameters-

    1 Same wire Length
    2 Same wire Diameter
    3 Same amount of copper
    4 All Core diameters to be the same

    The Basic Tests will include (120 x 9 = 1080)

    1 Inductance
    2 Capacitance per turn
    3 Capacitance End to End
    4 Resistance
    5 Self resonant frequency
    a Spectrum Harmonic analysis
    6 Using 10 standard Frequencies
    a Spectrum Harmonic analysis
    7 Radiation tests
    8 Magnetic tests
    9 Electrostatic Tests

    Each Basic test will be performed with a second coil : (120×160 )+(120x120x160)x6

    1 Of the same type
    16 basic mutual inductance Geometries
    a 10 Different mutual inductance distances

    2 of each other type
    16 basic mutual inductance Geometries
    a 10 Different mutual inductance distances

    So as you can see for basic testing alone I would need 120 coils, wound in at least 6 different wire gauges, making 720 coils. Each of those coils would need at least 6 different winding lengths, making 4320 coils. Now each on these can have different basic geometries, like long verses short, another 6 more types, making 25920, whew !! that is just to start before I test each one in multiple methods.

    I am sorry that I do not have that sort of resources, basically a full laboratory with 3 to 4 staff full time working for at least 2 years, would be ideal. Alas I am but one man with no resources, I will publish all my results in my book “Talking With The Birds” ASAP, good luck, I hope some of what I have here can help, Regards Arto


    • ansyar Says:

      hi Arto,
      Thank you so much for your help,

      My final project is about water fuel cell (WFC) as it has been made ​​by stan mayer, dave lowton, and ravi. did you ever know?

      in their paper, there is mounting bifilar coil is connected to the WFC. They use x turn, y SWG, and z inch ferrite rod of bifilar coil. but they do not explain why they use the value of x, y, z of the bifilar coil. I do not find there a detailed calculation. it makes me confused.

      I actually want to know the benefits of a coil in a circuit. Can you help me to explain?

      I have learned that the bifilar coil consists of two strands of copper wire that acts as the primary and secondary coils. My question is:

      bifilar coil is the same as the transformer or not?
      what effect a given bifilar coil in the circuit?
      how the resonance effect, is that what is needed from the bifilar coil for the system? and what are the benefits?

      sorry for the many questions because I’m still an amateur in this case and sorry if my english is not good.



    • chance Says:

      If you do it in the OpenSource well described and documented. You could collect data on each coil coming from the community.


  3. artojh Says:

    Hi Ansyar, this should help,


  4. Andy Says:

    Hi Artojh, I am working on a number of free energy devices and have a fairly good understanding of electronics and physics have wound a number of coils bifilar pancake solenoid quadfilar starship and believe you are truly demonstrating a great winding technique but I am Struggling to understand your diagrams am not sure if the numbers represent single turns or layers of turns and how it actually connects up. Was trying to work from the old coil pic on graph paper but the close up only shows a and b the chart shows up to d, the smaller diagram has 3 pairs ? up to c? please excuse my ignorance If you could make me understand how the winding all goes together I would be so grateful. am used to winding bifilar in series where two windings go on side by side at same time, so two starts two finishes. Start one is begining, finish one goes to start 2 and finish two is end. I can understand your first three diagrams where 1] you have a bifilar with two turns, 2] is a bifiliar with 2.5 turn showing capacitance and 3] the quadfiliar with 1.5 turns. If you could demonstrate with the same kind of diagram I should understand bear in mind i’m upside down here in UK this might be a drawback lol. Many thanks in advance.


    • artojh Says:

      Hi Andy,
      Thanks for checking the windings in detail, most people never understood my methods in the early 90’s, so I decided to unravel the knot in diagrams. What I have on this blog is only part of a draft from my book, where I have also included earlier ideas such as the magic square winding. I am posting an update at the end of this blog with a diagram that should help you understand what I had originally designed. The arrangement possibilities are more numerous than I can indicate on my diagram. Thanks Regards Arto


  5. Andy Says:

    Wow thanks for amazingly fast reply, I look forward to exploring your posting, I know what you mean with explaining your own work I do all sorts of jotting down that I guess really, only I can know what it means unless I clarify it more but not everyone as you say is really interested. I came across your blog by searching google with “spiral solenoid starship spiral coil” as I was debating with myself what coil I should use next on my wheel pulsed motor / generator as I am getting a feeling that I may be able to get it self running with a little more work. Just the back emf from the drive coil I am using is quite exciting and I am hardly feeding it .01 amps on a constant reading with 12v supply. But I need more speed with little more current to get the generation working am using heavy magnets but unable to get much over 100 rpm and coils don’t start generating till its over about 200 rpm so luckily bumped into your work!


  6. Andy Says:

    Also Arto, the reference you have on standard solenoid looks to me like 4 layers of 4 windings piled on top of each other but always starting from same end of coil which is something I have never fully understood because my thinking made me think this was required but then noticing that most commercial stuff is wound back and forth and I read somewhere I think, that it did not matter as long as the windings were neatly following on. Its hard to find out what really is correct without trying everything as you say. Was toying with the idea of lots of pancakes piled on top of each other in series but, do I need litz wire, should they be multifilar, ? its just so much work for nothing if it does not prove better results. I had quite good results with a series bifiar pancake coil using 7 strands of .4mm magnet wire twisted in drill chuck for tapping off an induction cooker but not a definate cop>1.


    • artojh Says:

      Hi Andy,

      Yes you are correct, you can wind it in either direction. The idea is to think about the actual placement, as each wire has an inductive and capacitive influence on all other wires, where the overall combination is much more than each part individually, like a living organism.

      The standard number sequence here would be slightly different if you wound it commercially as said, still the abstract Magic form would still be the same, it is the distance from each of the windings that will show up as unique harmonics adding to the open system with tunable elements to it local EM environment, also the inter-wing differential EMF’s are not uniform anymore. Magic Squares are like a form of controlled chaos.

      What is required is the free flow of the Ether through the coil system, using an organic wiring system, such as plankton growing from dilute chemical nutrients in its environment.

      I have added another pic relating to your question into the post, Regards Arto


  7. Andy Says:

    Arto, Thank you
    I say thank you, but if I could do something more to thank you let me know what that could be. I think now I can convert your number sequence for the magic square into a diagram similar to the first diagrams in the post, I will have a go at this and send you a link to it when complete. I will probably put it on my site and reference back to here from there as I am not sure how or even if I can add a picture on this blog, many thanks again for your time and help. If you would like to take part in my site or even develop it you are welcome, I have a filipino wife and 1 year old baby here in uk and at age 51 can’t keep up with everything so is somewhat neglected and my other site gets little attention aswell, but I would imagine you also are far to busy infact I would be happy to give you the site ( free if you are interested. The whole intention of the site is to get us all living in a more motivated cleaner environment.


  8. Andy Says:

    hmm, not so sure now I actually look at it, you see on the solinoid drawings I can accept the numbers as being the turns in order but with the magic square it seems the numbers can’t be turns because if they were you would be having wires coming of for coupling before winding even one layer, infact a single turn then wire coming of each end which somehow does not seem right if it is and this is how it works then please tell me, but what I am thinking is there would be so much straight wire running over/under other turns that the magic would possibly be lost, I feel so silly that I can grab some but not all of it but I believe god loves those who try.


    • artojh Says:

      Hi Andy,
      Remember all the wires are wound in pairs, the joining is at either the end of the coil. The numbers are also labels for the placement and location of each wire. I know this is not an easy design or system of winding, it took me years to figure out a new way of looking at coil engineering, then applying the abstraction into practical results. I suggest building a 4 layer 32 point connection board before tackling the Magic square wiring, the one on the blog I uploaded was a 3 layer 24 point connection board. The Magic square wiring is 4 layers with 2 input pair and 2 output pair which gives you 16 units of connections for each stator. The magic coil system was designed to have 2 stators which will give you 16 complete wire lengths that have multiple turns on each stator, which means each wire will represent one number placement on the magic square 4. I am sorry it cannot be simpler, good luck and regards Arto.


  9. Andy Says:

    That is wonderful, I feel quite sure I understand it now although I wanted to use just one coil if that will not work so well because they are designed to compliment each other I can add another but as I am using five magnets I would have to offset the second coil to pulse at the 3rd or second magnet. This might create an interesting unbalance to collect more from this. I was reading through quite a number of your other posts (impressed) my father is an artist, he is 87, I shall show him your work. Art and Electronics are often thought of as so separate yet it seems you have developed both complimentary.
    Kindest regards


  10. Andy Says:

    I started drawing up the connections for 4 layer at the bottom of the following pdf link but noticed that on the 3 layer diagram it seam A6 and B5 are ends of the same wire is this how it should be? is this a shorting technique ? I am asuming that blue and green is the same wire and orange and red the other?
    Sorry to be troubleing you so much if you look at the pdf you will hopefully agree am on the right path?
    regards Andy


    • artojh Says:

      Hi Andy,
      I have updated the file, I sent it before I had really finished it. My apology, I have been working on different parts of my book, getting close to finalizing the final content, I will make a new post shortly revealing another few more pages. Good luck with the build, I am very excited to see some of your results, Regards Arto.


  11. Andy Says:

    Ok I will work away with all that and will update you when I have done some work, thanks again its hard to find someone who is genuine and will share like yourself, so I will make it a priority to give you feedback.


    • artojh Says:

      Hi Andy,
      No need to sweat I have placed another diagram on my blog, completed as a magic square 4 system. Now you can choose from 880 magic square 4 arrangements. The rotor arrangement with 5 poles is OK with this coil system, or a possible expansion of this into a square 5 you can use the columns as each stator, this way you split the square into 5 parts. Regards Arto


  12. Andy Says:

    Arto, I am glad I am also motivating you. I have wound four bifilar layers was going to connect them as per corrected diagram but then started wondering what would happen with five or six layers and now you have given even more combinations I don’t have enough wire or cores to build every combination, much that it would be great to achieve that task! also you lost me again when you mentioned columns do you mean the 5 magnet columns .. no i doubt it. I wish we could meet to discuss this my email address is although I don’t mind discussing most stuff here for the benefit of others who may follow this thread my original idea was inspired by romero uk’s variation on the muller motor but there appears to be so many variants on pulsed motors for high efficiency or even cop>1 romero uk by the way pulled out due to a visit from some well dressed people who were not happy and I believe posed threats as well as confiscating his equipment but you can still find stuff on his replication. Have read a bit on the adams motor to get an idea on the principals and can’t really get my head around the coils getting cooler as they run but believe so lets move on. I also don’t get the picture of the square properly either but I know how to use the connection system so unless you advise different before i start will wind another one or two layers then get following one of the three connection patterns but adding the extra 2 or 4 wires (1 or two layers) suddenly taking my mind back about 35 years to high school maths is not enough but am doing what I can. If I don’t achieve overunity, I may go back in time instead!


  13. Andy Says:

    I appreciate that add more layers could mess up the system but not knowing how it all affects itself exactly makes me want to experiment but i don’t want to miss the benefits you have already found. I read somewhere that with ordinary solenoid coils the best proportions is diameter = 1.5 X length i.e. short fat coils but then this is no ordinary solenoid. cheers Arto


  14. Andy Says:

    Just had an idea Arto, if we were to work out what way the current is flowing on each link it may be beneficial to wind the links into a few turn on an air-core coil, then position it so that one of the remaining magnets energizes each link in the right direction of current flow to encourage the pulse in the other 2 coils .. just a thought will test the original magic square first though have stuck to four layers as the wire ends were a little to much to increase on with first wind besides the connection of the magic is not as simple to add to as the first setup, am just starting my second coil.I will also need to modify my circuit so i have more control over pulse width.


    • artojh Says:

      Hi Andy,
      Your idea has great merit, this is the type of thinking that will get some interesting outcomes. This project will the hallmarks of originality and should lay a foundation for a different and unique design element that Robert Adams had hoped for my work in 1996. I am working on a pulse motor switching element utilizing the unique Lamda Diode, when my research is complete i will send you the diagram, it should work well in the magic square coil design due to its similarity of having a complimentary pair in reverse gate design. Great work and good luck on the build, Regards Arto.


  15. Andy Says:

    Thanks Arto
    I have placed a few videos here they are not edited and a bit long so will only be up temporary but I feel I owe you to see what I actually am at ith all the help you have given! off to bed now its gone 4am here.


  16. Andy Says:

    Hi Arto
    Have resurfaced, just connecting up the two coils now. There is a Man who wrote a very detailed book on free energy devices called Patrick Kelly. I have communicated with him on several occasions by email and he was very helpful but like yourself is very busy updating his book constantly so I don’t like troubling him to much but I have emailed him to inform him of your work as I have never seen this technology anywhere else and thought he may be interested. Here is his site in case you have never come across his work
    regards Andy


  17. Magic Square Coil Technology | Artojh's Renderings Says:

    […] have decided to make a new blog rather than updating an older one, refer to I would like to thank Andy, he  has prompted me to finish my chapter on coil geometry, with a new […]


  18. Dale Says:

    Hello Artojh,
    This is a great site. Thank you for putting it up. In your experimentation, which electromagnet gives the greatest field strength? As an example, say a 24V DC Pulse to a electromagnet with a solid core, would a trifilar coil give a stronger field or a bifilar wound coil?


    • artojh Says:

      Hi Dale,
      Thanks, the issue of Magnetic Field Intensity(H) is only of concern when you need to maximize your forces involved(Amps per meter). If you want a large Magnetic Field Strength (B field), you will still need a large H(large draft of current), then this intensity can be tweaked by using flat mult-filar coil geometry (central sharp focus, low self induction), the best method is to stack many flat multi-filar pancake coils on top of each other, oriented in the correct way, where poles and the geometric wiring are reinforcing each other(CW + CCW + CW + CCW etc) you could easily draw 1000 amps in a small desktop size of enough to blow your fuse-box. The design is similar to

      I cannot be of more help than this, your particular design for pulsing might not be suitable, the best is to build one of each type and compare results. Most of my motor pulse circuits were of low field strength, this is where I found the best results for self oscillations and field interactions, I always worked so the circuit was very sensitive and could even pick up my arm tensing, my magnets were 0.1 Tesla and much lower. Regards Arto.


  19. Dale Says:

    Hello Arto,
    Thank you for your prompt reply. Are you in Mt Pritchard? I am in Canberra.

    What size wire do you recommend to generate the largest magnetic field intensity? I was thinking of .25mm by 100 turns using your bifilar pancake design. I thought that having a CW then CCW design would actually cancel out each magnet field? Do I join the B1 and A2 wires together?

    Do you have your own coil winding machine? I don’t really have the means to try several different coils so I need to make sure I do it right first time. Do you use formulas to determine field strength?



    • artojh Says:

      Hi Dale,
      Great to have another Aussie visit. As I can see that it is a small unit, using 0.25mm wire and 100 turns, here goes. If you use a 10mm core, then each winding stack will be 25+10+25 = 60mm diameter, thus means winding 2 wires of 50 turns each in between 2 disks like this pic.

      100 turns is a small number of turns for a reasonable strength electromagnetic pulsing coil, I would suggest each stack be this number and at least 8 stacks will be a good number, giving you 800 turns and a depth of only 2mm, best results would be a stack of 20 or more giving you 5mm depth and 2000 turns. connect all coils in series internally and the the re-loop the 1st wire end and 2nd wire beginning, giving you a bi-filar multistage coil, compact and tight.

      I use many formulas and quite often make my own, the best rule of thumb is(using mtrs):
      Inductance L = ( u0 x ur x N^2 x A ) / Leng = in henries
      N = number of turns = easiest to increase
      uo= 4 x pi x 1e-7 – permeability constant
      ur= relative permeability = ferrite aprx 600, Iron aprx 5000
      A = cross sectional area of core
      Leng = length of coil = shorter the better
      Best to approximate to get a ball park figure, then use a inductance meter to get accurate results.
      B= u x H = magnetic field strength
      u = u0 x ur
      If you are creating resonant coils, use an oscilloscope to find your peaks. You can get a lot of great formulas in text books etc, but always check against a meter to be sure. I know this a little rough, but I hope this will help. Regards Arto.


      • Dale Says:

        Hello Arto,

        I greatly appreciate your help and your diagrams. Are the disks that you describe made of soft iron for greatest magnetic field strength? Do you know where I can buy these disks? Do you know how thick the disks have to be?

        Just to clarify, wire up 20 x .25mm flat pancake coils of 100 turns and join them together in a cw then ccw then cw then ccw fashion?

        As you are only 2 hrs away, Do you do any tutoring on multifilar coils?



      • artojh Says:

        Hi Dale,

        The disks are only to wind the flat coils(hard plastic), spaced at 0.25mm apart, then a dab of epoxy in the slot, then separate, then wind again in CCW, epoxy, separate, etc Once you have 8 flat coils, 4 CW, 4 CCW, then you join the inner wires as per the diagram, then slide over core, then joint the 1st wire end and 2nd wire beginning, Tape the whole thing with rubber molding tape, presto a multi-stacked bi-filar coil.

        Regarding any tutoring or such, just email me.

        Regards Arto.


  20. Dale Says:

    Hello Arto,
    Thank you for your instructions. In the diagram above, would I then join the outer wire of the ccw coil to the outer of the cw coil? Then the inner wire of the cw coil to the inner wire of the ccw coil.

    Also, with a larger core with a larger cross sectional area, will this dramatically reduce the magnetic field generated?

    Any idea what epoxy is good for making the coil? I’m wondering if cyanoacrylate glue may burn through the coating on the copper wires.



  21. artojh Says:

    Hi Dale,

    Yes you are correct, remember you are winding a pair of coils in CW so you will have 2 wires to join not just 1. Regarding the core, the permeability is a greater factor here, and yes, the larger cross section will not improve the intensity. If you use superglue it will be OK, just use minimum as it turns the wire cloudy and forms capillary channels between any wires touching, makes a messy situation if you are not slow and deliberate.

    Best to make a simple test coil and makes sure your craftsmanship and methodology is sound. Good luck Dale, I hope it is a good beginning for some great experimentation.

    Regards Arto


  22. Dale Says:

    Hello Arto,
    Is it best to layer the coils, one on top of the other next to the core or is it best to layer them vertically on the core itself? Hope this makes sense?



  23. Dale Says:

    Hello Arto,
    I have posted an image:
    . Is this correct?



  24. Dale Says:

    Hello Arto,
    I added spaces between the coils just to show the connections.



  25. artojh Says:

    Hi Dale,

    I am not quite sure of your configuration, probably best to send a photo of what you have done.

    If you have wound each flat coil separately, then you need to join them. Joining near the core is problematic, best to connect a pair , so the join is clean, then put on the core, then join the outer wires, I think this is what you haves asked.

    Connect all matching pairs CW+CCW, then put the whole lot on the core, then join the outer connections, then cover in wax so nothing comes apart or any suitable non volatile substance such as electrical liquid rubber. Check each coil connection before continuing, you should have a very powerful, electromagnet in a small footprint.

    I hope this helps

    Regads Arto


  26. Dale Says:

    Hello Arto,
    Thanks for getting back to me. Did you seel the picture I posted? It joins the coils firstly from the centre to the next centre and then from the top to the top then centre to centre again and so on. I followed your previous drawing of doing this.
    Each coil has a top wire and a centre wire. I will send you another picture to help explain it.

    You are always helpful


  27. Dale Says:

    Hello Arto,

    In your picture above: magorient1a_by_valnor-d7kbck7.jpg I am joining the wires together going by the top picture. You have 2 coils where I am doing 20. Yes glutten for punishment.

    In your picture the (-) from the bottom end of the 2 coils joins on to the (+) of the next coil. So that the centre wire ends of 2 coils join then the top wire ends of 2 coils join and so forth. Does this clear this up? Am I on the right track? Is this pattern how you would join 20 coils together?



    • artojh Says:

      Hi Dale,

      Yes that would be the correct method, do it in pairs, and only join the outer ones once they are all on the core. After all the joining and waxing, you can remove it from the core if you wish, but I would suggest not to.

      20, that should make it interesting, good luck, and remember have fun.

      Regards Arto.

      Liked by 1 person

      • Dale Says:

        Hello Arto,
        Here is the picture:

        I’m doing one coil at a time, then another and then joining those two together and then the next one and so on… I see what you are doing, doing two at once. The penny just dropped.

        Also, you can buy self bonding flat copper wire which will also help.



  28. Dale Says:

    Hello Arto,
    On the theoretical side, does having 20 coils as ooposed to 2 create more resistance in the coil and therefore reduce the strength of the electromagnet?


    Liked by 1 person

    • artojh Says:

      Hi Dale,

      Yes 20 coils will create more resistance, because there is more wire thus all other parameter must be increased, R=V/I. There are 3 things Magnetic Flux Density, Magnetic Coercion and Magnetic Field intensity. each of these will be affected by your choice of, geometry, input voltage, input amperage and resistance.

      When you say strength, do you mean cohesive force, magnetic intensity or flux density, they will all go up as you increase your wire resistance, amperage, turns and voltage. Your core material will saturate long before you can reach any maximum possible, this is why in magnetic research they use air cores.

      Best to study the B/H curves of meta-materials so you flux increases can be accommodated.

      As you are using thin wires, you are limited to a lower amperage, which means your amp turns will be low(H), this means by making more turns you can compensate, the trade off is higher resistance and higher voltages, I am not sure of your application , so all my advice can only help to clear any misunderstandings of basic electromagnets.

      I do not necessarily apply theory as much as a pathway to practical usage, new ways of designing and a different approach to electrical engineering. Any new theories will emerge from attempting new combinations and elements of design that either have been ignored or misunderstood.

      Regards Arto


  29. Dale Says:

    Thanks Arto,
    My voltage is 30Volts at 1A DC Pulse. As my amperage is low, thats why I am using .25mm wire but at 100 turns per coil. Total of 2000 turns on a laminated core (less eddy current loss). I’m wanting to creat the strongest magnetic field I can with my current limitations. R=V/1 = R=30/1 R=30 Ohms.

    Should I use less turns or less coils?



  30. Dale Says:

    Hello Arto,
    I fear I may not have enough voltage and current for the 20 x 100 turn electromagnet. From my calculations: 0.25mm has a resistance of .339 ohms per meter. Due to electromagnet size, I can achieve 3 turns per meter. For 100 turns per coil I need 33 meters of wire which equals 11.187 ohms per coil. For 20 coils (2000 turns) my total wire resistance is 223.74 ohms.

    Using ohms law, I=V/R = 30 V/223 Ohms I am getting only 0.134Amps across the coil. Ironically, the Max current carrying capacity of 0.25mm 30 AWG wire is 0.142 Amps and the maximum voltage = 31.66V. Does this indicate that using the 2000 turns (20 coils) will be better than say only using 1000 turns (10 coils) ?

    Using the online calculator at: . I am generating a magnetic field of 35903 Gauss. (Turns: 2000, Length 14cm, Radius .75cm, current 1A, Permeability Iron 200 relative) This figure appears very high, am I doing my calculations correctly?

    Am I on the right path?


    Liked by 1 person

    • artojh Says:

      Hi Dale,

      The calculation java app, seems ok for use with general solenoids and those type of designs and system. Your design has already moved beyond standard linear formulas, as you have found out by trying to put some of the parameters into the CalcTool.

      1)First is to measure the inductance of each coil,
      2)then measure after you add the core,
      3)then measure the total inductance connected,
      4)then measure the total inductance with the core added. This procedure will give you the permeability of the core.

      The next step is measure your TC(Time constant) of your coil in all four variation as written above,

      The same with the resistance.

      Then use an oscilloscope to measure all 4 variations using, different voltages and amperage’s with a variable power supply.

      I cannot advise on your results as only by ascertaining accurate data and viewing the limits of your system. The general assumption as I advise much earlier is that, thicker wire + more amps = greater B. You must remember the B is highly focused in a flat coil.

      Your design at what ever power you will use is set to a limit of the materials you use. I would best advise to use an oscilloscope at this point, there are no simple calculations that can give you the answers you seek. The main question you ask is 10 better than 20, I cannot answer this, as magnetics and coils are innumerably linked by the number of turns, the limits are now set by the wire thickness and it weakness to higher currents fusing the wire strands.

      The capacitance and its TC of the coil system also needs to measured. So TC1 of the coil inductance, TC2 cap of coil, together they will tell you the whole story.

      I hope this has helped.

      Regards Arto


  31. Quadrifilar Coil | Artojh's Renderings Says:

    […] and the second volume, I am finding small errors that need to be corrected. The picture on my blog Multifilar can easily be replaced, but my book has been in print for a year, so I am including the file […]


  32. Laurence Says:

    Very good blog post. I certainly love this site. Keep it up!

    Liked by 1 person

  33. Edvin Savickas Says:

    Hi Artojh, I was wondering if your coils help in self levitation device or does any coil work just fine? Thank you, hope you see this.

    Liked by 1 person

    • artojh Says:

      Hi Edvin,
      You could engineer these coils in such a way that another coil could have its multiple poles be in repulsion. A coil system could be designed like the Halbach magnetic array comes to mind, and flipping the polarities by rerouting the coil wrapping in a switch array could be a way of controlling any movement you need. The some interesting design elements that are presented in my blog is a way of creating multi-resonant coil groups that could act like key filtering of information or energy from a particular frequency band.
      When it comes to levitating magnets and coils, the simple single direction solenoid can be used quite productively.
      I hope this helps, Regards Arto.


  34. Warner Mcphillips Says:

    Rima Lorenzen

    blog topic


  35. Raphael Says:

    hello there artojh … I saw you liked my post ‘AAA Day in the LIfE of the 137 SS Mystic – August 3, 2013 – N, SHE, NUN, where Egypt hid the swastika and the number 35’ … so I followed you here … (btw I have 600+ posts on two blogs)

    this might be your lucky day … or perhaps not … here is a video I would to share about the torus which serves as the model for all subsequent windings … however as you can see this kind of technology is beyond your ability to recreate what requires much $$$

    enjoy …

    here again is where what I offer brings everything down to a simple algorithm yet to be appreciated and fully understood in this age of ‘too much information’

    ACHIRAL >>> CHIRAL >>> ACHIRAL >>> CHIRAL >>> forever and ever

    let me explain >>> a torus or donut which serves as the backbone/skeleton for all types of windings can be geometrically defined as ACHIRAL, meaning it has both rotational and reflection symmetry.

    however as the video I offered illustrates the ACHIRAL symmetry is breached by five-fold twisting (mobius) and results in CHIRAL asymmetry … this is THE key … CHIRAL has only rotational symmetry.

    the reason I suggest this simple idea is KEY is because that is THE one idea we can identify on all levels of scaling as being vital to a ‘process’ called life and death … same algorithm is identified in the ‘garden of eden’, in mitosis/meiosis, and ‘precession of the equinoxes’ … all levels of scaling … from the quantum to the relative scale.

    including the hypothetical algorithm called Genesis;
    PERFECT ACHIRAL symmetry gets breached and CHIRAL life emerges less than perfect … but containing the seeds of ACHIRAL destiny …

    ALL LIFE IS CHIRAL is a statement of fact.
    The chiral anomaly is KEY to penetrating the secrets of life.


    swastika sage of the social media age


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