Forums

Coils

Started by Chiron January 26, 2012
I've wanted to check out some things using big coils - not the sort used 
for RF circuits, but large coils such as might be found in a Tesla coil.  
I don't have the funds to special order them or to buy them pre-made 
(assuming they even come that way).  I expect I'll have to wind my own... 
but...

How the heck do you do that?  What sort of arrangement would work for 
that?  Trying it by hand left me exhausted and with poorly-wound coils of 
insufficient turns.  Surely there is some simple arrangement whereby you 
can feed in wire and magically get out coils.

Can anyone point me in the right direction with this?  I'd appreciate 
it.  I've already tried Google, with little success.

I also tried buying a used "coil-winding machine," but it's just a 
powerful motor with a chuck for holding the coil's form.  No speed 
control at all, no reasonable controls.  There is a toggle switch that 
selects the motors direction, and doesn't even let you turn the damned 
thing off.  If it's plugged in, it's rotating one way or the other at 
full speed and power.

I'd appreciate any helpful ideas.  Thanks.


-- 
That's odd.  That's very odd.  Wouldn't you say that's very odd?
In article <kQkUq.1524$1B1.1269@newsfe14.iad>, chiron613@gmail.com 
says...
> > I've wanted to check out some things using big coils - not the sort used > for RF circuits, but large coils such as might be found in a Tesla coil. > I don't have the funds to special order them or to buy them pre-made > (assuming they even come that way). I expect I'll have to wind my own... > but...
[snip]
> I'd appreciate any helpful ideas. Thanks.
Googling on 'diy testla coil' brought up: http://www.rmcybernetics.com/projects/DIY_Devices/homemade_tesla_coil.htm Car ignition coils from a scrapyard are one option.
On Thu, 26 Jan 2012 17:14:39 -0600, Randy Day wrote:

> In article <kQkUq.1524$1B1.1269@newsfe14.iad>, chiron613@gmail.com > says... >> >> I've wanted to check out some things using big coils - not the sort >> used for RF circuits, but large coils such as might be found in a Tesla >> coil. I don't have the funds to special order them or to buy them >> pre-made (assuming they even come that way). I expect I'll have to >> wind my own... but... > > [snip] > >> I'd appreciate any helpful ideas. Thanks. > > Googling on 'diy testla coil' brought up: > > http://www.rmcybernetics.com/projects/DIY_Devices/
homemade_tesla_coil.htm
> > Car ignition coils from a scrapyard are one option.
Thanks, Randy. However, I am not particularly interested in making a Tesla coil; I simply mentioned that to give an idea of the types of coils I was interested in creating. Big coils, lots of windings, air core, potentially very high voltages and relatively high frequencies. Some with fairly high magnetic flux density, perhaps. I am looking for flexibility. I've used ignition coils previously, which are OK for some uses. Unfortunately, they are limited. IIRC, they have an iron core which limits their upper frequencies. The solution, as I see it, is to wind my own coils so that I can choose their size, wire gauge, number of turns, core, and other variables. -- Some of the things that live the longest in peoples' memories never really happened.
On Fri, 27 Jan 2012 00:06:28 GMT, Chiron <chiron613@gmail.com> wrote:

>On Thu, 26 Jan 2012 17:14:39 -0600, Randy Day wrote: > >> In article <kQkUq.1524$1B1.1269@newsfe14.iad>, chiron613@gmail.com >> says... >>> >>> I've wanted to check out some things using big coils - not the sort >>> used for RF circuits, but large coils such as might be found in a Tesla >>> coil. I don't have the funds to special order them or to buy them >>> pre-made (assuming they even come that way). I expect I'll have to >>> wind my own... but... >> >> [snip] >> >>> I'd appreciate any helpful ideas. Thanks. >> >> Googling on 'diy testla coil' brought up: >> >> http://www.rmcybernetics.com/projects/DIY_Devices/ >homemade_tesla_coil.htm >> >> Car ignition coils from a scrapyard are one option. > > >Thanks, Randy. However, I am not particularly interested in making a >Tesla coil; I simply mentioned that to give an idea of the types of coils >I was interested in creating. Big coils, lots of windings, air core, >potentially very high voltages and relatively high frequencies. Some >with fairly high magnetic flux density, perhaps. I am looking for >flexibility. > >I've used ignition coils previously, which are OK for some uses. >Unfortunately, they are limited. IIRC, they have an iron core which >limits their upper frequencies. > >The solution, as I see it, is to wind my own coils so that I can choose >their size, wire gauge, number of turns, core, and other variables.
--- That's all true but, if you're asking for help, very little can be offered without your stating what you want to do. -- JF
On Thu, 26 Jan 2012 18:28:58 -0600, John Fields wrote:

<snip>

> That's all true but, if you're asking for help, very little can be > offered without your stating what you want to do.
I want to wind coils. That is what I want to do. I don't want to *have* coils, per se; I want to *wind* my own coils, so that I can adjust them for whatever variables seem interesting, necessary, or otherwise useful. I do not have in mind any particular project to build. I want to putter around with them, as my interests may lead me. So maybe I'll want a large magnet; or a transformer of some sort; or a Tesla coil, Oudin coil, hell, I don't know, maybe even motor windings. Maybe think of it as a sort of "teach me to fish" kind of thing. Instead of needing to track down this kind of coil, or that kind, I'd be able to make whatever I needed. -- Being popular is important. Otherwise people might not like you.
On Jan 26, 5:54=A0pm, Chiron <chiron...@gmail.com> wrote:
> I've wanted to check out some things using big coils - not the sort used > for RF circuits, but large coils such as might be found in a Tesla coil. > I don't have the funds to special order them or to buy them pre-made > (assuming they even come that way). =A0I expect I'll have to wind my own.=
..
> but... > > How the heck do you do that? =A0What sort of arrangement would work for > that? =A0Trying it by hand left me exhausted and with poorly-wound coils =
of
> insufficient turns. =A0Surely there is some simple arrangement whereby yo=
u
> can feed in wire and magically get out coils. > > Can anyone point me in the right direction with this? =A0I'd appreciate > it. =A0I've already tried Google, with little success. > > I also tried buying a used "coil-winding machine," but it's just a > powerful motor with a chuck for holding the coil's form. =A0No speed > control at all, no reasonable controls. =A0There is a toggle switch that > selects the motors direction, and doesn't even let you turn the damned > thing off. =A0If it's plugged in, it's rotating one way or the other at > full speed and power. > > I'd appreciate any helpful ideas. =A0Thanks. > > -- > That's odd. =A0That's very odd. =A0Wouldn't you say that's very odd?
No magic devices. We use a lathe to wind coils. Built a little spool holder with adjustable 'friction', turn on the lathe and start counting. (We've added a turn counter.) Scatter wound coils are pretty easy, if you want something more 'controlled' then our production peolpe put a layer of tape on after each layer or two. Maybe a foot operated AC switch would help make your coil winding machine more 'user friendly'. George H.
George Herold wrote:

> Maybe a foot operated AC switch would help make your coil winding > machine more 'user friendly'.
http://www.youtube.com/watch?v=YqErTwU1rSE Look at 0:06 and starting at 1:02. See how he's adapted a cable to allow foot control of the motor speed? As soon as I saw that I thought "Coil Winder"! The Foredom FCT-1 is an electronic solution that would plug right in without any 'metalworking heroics'. Nifty! --Winston
On Thu, 26 Jan 2012 22:54:08 GMT, Chiron <chiron613@gmail.com> wrote:

>I've wanted to check out some things using big coils - not the sort used >for RF circuits, but large coils such as might be found in a Tesla coil. >I don't have the funds to special order them or to buy them pre-made >(assuming they even come that way). I expect I'll have to wind my own... >but... > >How the heck do you do that? What sort of arrangement would work for >that? Trying it by hand left me exhausted and with poorly-wound coils of >insufficient turns. Surely there is some simple arrangement whereby you >can feed in wire and magically get out coils. > >Can anyone point me in the right direction with this? I'd appreciate >it. I've already tried Google, with little success. > >I also tried buying a used "coil-winding machine," but it's just a >powerful motor with a chuck for holding the coil's form. No speed >control at all, no reasonable controls. There is a toggle switch that >selects the motors direction, and doesn't even let you turn the damned >thing off. If it's plugged in, it's rotating one way or the other at >full speed and power. > >I'd appreciate any helpful ideas. Thanks.
I've wound a number of Tesla coils and a 1 KW induction coil with ~13 miles of wire in the secondary... According to the DC resistance, I nailed the length of wire to within 300 feet of my design goal - not too shabby out of 13 miles. First few TC's I did were by holding the PVC tube and guiding wire on while rotating the tube in my hands. That got old fast. I built a coil winder with a large PM DC motor. Fixed the motor horizontally, to a 2X6 plank ~50" long. I used a reel drive motor from a computer (1" X 15" tape reels), but there's lots of "treadmill motors" these days with similar power and size on the surplus market. For the mandrels, I laminated a pair of spruce 2X4's together, drilled a hole through the center and mounted a short length on the motor by just drilling the hole undersize and beating it on with a hammer (healthy motor with a 3/8" X 2" shaft). I turned the mandrels using a variable power supply (24 volt battery charger with a variac to control voltage) and some wood chisels, rasps and sandpaper to make a friction fit to the 1-1/2" to 3" PVC coil forms. Turning wood is a lot of fun.... The fixed center of my winding lathe, was a construction out of wood using a 3/8" bolt as the lathe "center." Turn two mandrels and leave one on the motor and one on the center, with the PVC tube between. Winding is a snap - took less time to build the, admittedly crude, lathe, and wind the 3" wide long coil, than it would have taken to wind the coil alone. I wound a total of 12 coils in the 2" to 4" diameter range and had loud noisy sparks 8 feet long out of some of them. They can easily be coated with thick layer of epoxy or varnish by leaving the coil on the lathe, rotating it slowly, while using a credit card to spread the epoxy evenly. It rotates slowly while the epoxy sets up so there are no sags and you get beautiful results. I just set the power supply so it is tensioning the wire then hold the wire back with one hand and guide it on with the other as the motor turns. Precut masking tape holds the wire in place long enough to cement the end down (under tension). The induction coil was the same deal, but I made four large bobbins out of 3" PVC for the cores, and 1/8" thick Plexiglas donuts for the end plates. They are 3-1/3" wide, since I had plain adding machine paper on rolls to use as layer insulation. I'd wind a layer using the TC winder with one mandrel to hold the bobbin (and a shorter bed on the lathe for this project). A layer took about 2 minutes using #32 AWG wire. Then tape it in place long enough to paint it with quick drying varnish to hold the turns, wrap it with a layer of paper and do another. Took about a week of spare time to finish 4 bobbins with some 24 layers on the outside coils and 30 on the inside ones. Took about a month total to build the induction coil. I wound the primary in four layers and brought out the starts and finishes so I could wire them in series or parallel to use as an AC HV transformer or DC induction coil. AC performance is ~10,000 volts and DC unknown (but jumps a 5" spark with no problems) The whole thing got vacuum impregnated with wax (using my pressure cooker on the range top with a vacuum pump attached to it filled with molten wax - the wound bobbins soaked in the oven overnight on "warm" to get the wax to flow easily) My stove is electric - I wouldn't do it that way with gas since the paraffin is flammable and the varnish is hot and out gassing residual solvents when the vacuum pump is running. Hotplate outdoors with a fire extinguisher standing by makes more sense.... Oak box, porcelain conical turret insulators, with brass wood screws, and a largish 1930's X-ray machine ammeter on the primary, and switch box to serve different primary combinations for different voltages. The coils are potted in wax, the iron protrudes out either side of the box. Weight is ~35 pounds and it should have handles or wheels on it. Another, perhaps easier, way to do it is with "pies." Bobbins are only 1/8" wide with plastic film side plates, and the wire is jumble wound on - depending on the large number of bobbins to provide insulation between layers. I was working from a 1930's book on the subject and just adapted what they had to modern materials. I use the induction coil to excite the Tesla coils - I found that up to around 200 hertz the TC performs much better. They resonate at ~100 KHZ. Higher and either the iron loses are too great or the waves aren't damped out before the next spark comes along.
On Fri, 27 Jan 2012 05:50:41 -0800, George Herold wrote:

> On Jan 26, 5:54&nbsp;pm, Chiron <chiron...@gmail.com> wrote:
<snip>
> > No magic devices. We use a lathe to wind coils. Built a little spool > holder with adjustable 'friction', turn on the lathe and start > counting. (We've added a turn counter.) Scatter wound coils are pretty > easy, if you want something more 'controlled' then our production peolpe > put a layer of tape on after each layer or two. > > Maybe a foot operated AC switch would help make your coil winding > machine more 'user friendly'. > > George H.
Thanks, George. Maybe I can work something out with this motor I've got (the alleged "coil winder." Its one advantage is that it already has a counter on it. I think a foot-operated switch would be a great idea. I wonder whether there is any sort of foot-operated switch that lets you adjust the speed... that would be a major help, since this motor turns faster than I can feed in wire (10,000 RPM). I've been seeing people talking about PWM. I've never worked with that, but it might be something to try for the motor. -- If you learn one useless thing every day, in a single year you'll learn 365 useless things.
On Fri, 27 Jan 2012 06:20:41 -0800, Winston wrote:

> George Herold wrote: > >> Maybe a foot operated AC switch would help make your coil winding >> machine more 'user friendly'. > > http://www.youtube.com/watch?v=YqErTwU1rSE > > Look at 0:06 and starting at 1:02. > > See how he's adapted a cable to allow foot control of the motor speed? > > As soon as I saw that I thought "Coil Winder"! > > The Foredom FCT-1 is an electronic solution that would plug right in > without any > 'metalworking heroics'. > > Nifty! > > --Winston
Thanks, Winston. That sort of foot-operated switch, that allows variable speeds, sounds perfect. The guy who made the video seems very inventive. -- Have no friends not equal to yourself. -- Confucius