An interesting thought:
I've been reading up on air-core inductors and discovered the importance of maintaining symmetrical cross-section (thickness vs. width) with the proper compromise of diameter vs. inductance per turn--I think I wrote that correctly. Brooks came up with the ideal value for an air-core ratio in 1931.
Here's my thought: Bifilar wound inductors that are fed opposing fields are great in an iron core choke, but in an air-core inductor, do the two coils interfere with magnetic coupling--read inductance generated--thereby weakening the coil. In short, would it be more productive to place two separate inductors side by side, and let them cancel, rather than interweave the two chokes? Wouldn't you create a denser magnetic field if the wires are tightly packed rather than separated by a different wire carrying a different signal?
The two inductors are out of phase in a balanced topology, correct? With the bifilar layout, it seems to me that every other wire is an "impurity" preventing efficient magnetic coupling.
Or am I just nuts?
I've been reading up on air-core inductors and discovered the importance of maintaining symmetrical cross-section (thickness vs. width) with the proper compromise of diameter vs. inductance per turn--I think I wrote that correctly. Brooks came up with the ideal value for an air-core ratio in 1931.
Here's my thought: Bifilar wound inductors that are fed opposing fields are great in an iron core choke, but in an air-core inductor, do the two coils interfere with magnetic coupling--read inductance generated--thereby weakening the coil. In short, would it be more productive to place two separate inductors side by side, and let them cancel, rather than interweave the two chokes? Wouldn't you create a denser magnetic field if the wires are tightly packed rather than separated by a different wire carrying a different signal?
The two inductors are out of phase in a balanced topology, correct? With the bifilar layout, it seems to me that every other wire is an "impurity" preventing efficient magnetic coupling.
Or am I just nuts?
Re: An interesting thought:
No and yes!
I have had a test setup with bifilar air core inductors....works rather well
Magura
carpenter said:
Here's my thought: Bifilar wound inductors that are fed opposing fields are great in an iron core choke, but in an air-core inductor, do the two coils interfere with magnetic coupling--read inductance generated--thereby weakening the coil. In short, would it be more productive to place two separate inductors side by side, and let them cancel, rather than interweave the two chokes? Wouldn't you create a denser magnetic field if the wires are tightly packed rather than separated by a different wire carrying a different signal?
The two inductors are out of phase in a balanced topology, correct? With the bifilar layout, it seems to me that every other wire is an "impurity" preventing efficient magnetic coupling.
Or am I just nuts?
No and yes!
I have had a test setup with bifilar air core inductors....works rather well
Magura
Oh Magura, you think I'm a nut, don't you?
I'm running bifilar wound inductors at present. They work fine. I'm also going to try running a pair of air-chokes side by side to see if there's a difference.
Admittedly, the best way to glean an answer is to do the work--perform the experiment.
Magura, from what I've read, you really are making superb inductors. They're somewhat rounded on the edges, like a doughnut, correct? The article I read suggested that's the most desired shape, but difficult to obtain. I'm so fond of "unobtainium"; always enjoyed a challenge.
I'm running bifilar wound inductors at present. They work fine. I'm also going to try running a pair of air-chokes side by side to see if there's a difference.
Admittedly, the best way to glean an answer is to do the work--perform the experiment.
Magura, from what I've read, you really are making superb inductors. They're somewhat rounded on the edges, like a doughnut, correct? The article I read suggested that's the most desired shape, but difficult to obtain. I'm so fond of "unobtainium"; always enjoyed a challenge.
Well, to tell you the truth, I know for a fact that you're a nut!
As for the inductors, I have made experiments with dougnut shaped inductors, which is actually not that hard to make, but I have not been able to measure or hear any differences. The inductors I made for my ZV7TJCCSX-whatever are square cross section inductors.
Magura
As for the inductors, I have made experiments with dougnut shaped inductors, which is actually not that hard to make, but I have not been able to measure or hear any differences. The inductors I made for my ZV7TJCCSX-whatever are square cross section inductors.
Magura
Magura said:Well, to tell you the truth, I know for a fact that you're a nut!
As for the inductors, I have made experiments with dougnut shaped inductors, which is actually not that hard to make, but I have not been able to measure or hear any differences. The inductors I made for my ZV7TJCCSX-whatever are square cross section inductors.
Magura
they're usually dumb...........those inductors.............
round or square
'till radius in any angle (if former is,God forbid, rectangle) is 'nuff big.........inductor is 'nuff dumb to know that he can be bad......
anyway-density of winding is much more important than this trivia
Magura said:
Exactly! It's 99% a matter of craftmanship.
Magura
hehe
it's almost boring how clever we are
ps.
steen's back.........
I can imagine it in last few days of vacation.........junky like........"what to build next,what to build next........."
edit:
to be serious for change.........it was great surprise to me several yrs ago,when I realize that is much easier winding some hefty dia wire than tiny one...........2mm dia is just dream to work with..........
Magura said:
Ok, it's time to up your medication. That is just about as contrary to my experience as it could possibly get! Or you're just not winding that many inductors, cuse the big 2mm wire is sure tough to wind well.
Magura
you say that 0,7 is easier........?
no matter what former you have -it's easier to ensure nice fill with 2mm;
when I must make some chokes for spks (and I do that more than xformers and power chokes) I must use sort of winding machine I have ;
when I need to make big ones (for woofs) usually I do this on the same lathe where I make formers....even without taking out former from lathe head.........and guiding 2mm wire just with gloved hand.....
btw-that 2mm wire you use-is it soft or sorta hard?
mine ( I have just 5-6 kilos more) is more than 30 yrs old ....and brown as coffee........and pretty soft
hehe
you are right about medication...back to work
Ya watching me??
All metals needs to be "Glowed out" so to speak if they are to be soft. Copper, steel whatever, make it a bright red and slowly cool it and it will be soft in your hands
Basic knowledge! One of you guy's materials didnt fit the bill I once had a spool of 5 mm copper that I could bent with my fingers.Steen
steenoe said:Ya watching me??
All metals needs to be "Glowed out" so to speak if they are to be soft. Copper, steel whatever, make it a bright red and slowly cool it and it will be soft in your hands
Steen
Hmm, Steen, it can't be true I have to keep an eye on you all the time ;-)
If you heat steel and let it cool down slowly, you're right, but for copper it is exactly the opposite that is called for. You heat it till it glows, then throw it in a bucket of water. Aluminum works pretty much the same, but turns hard over time.
Nothing wrong with the materials, but the size of the inductors in question makes 2*1.9mm wire a tough call
Magura
Magura said:
Hmm, Steen, it can't be true I have to keep an eye on you all the time ;-)
If you heat steel and let it cool down slowly, you're right, but for copper it is exactly the opposite that is called for. You heat it till it glows, then throw it in a bucket of water. Aluminum works pretty much the same, but turns hard over time.
Nothing wrong with the materials, but the size of the inductors in question makes 2*1.9mm wire a tough call
Magura
Thanks for enlightening on the subject. My memory may have been a bit rusty? I was just about sure, that I was right!! I will dig out my old textbook and have a look
Steen
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