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Production and design of high Q inductors with 3D printed hardware
sourcecharge:
yada yada yada, winding toroids sucks...
ch_scr:
Looks nice! I might be a bit dense, but how does a "sectional winding" go on the core?
I suppose you do all the windings in this sector, then somehow (how?) fix them to the core, remove the next mold sector rinse & repeat?
If so, are all the sectors then connected in series or individually brought out? And how does the "core hardware holder" fit into the equation?
sourcecharge:
--- Quote from: ch_scr on September 02, 2019, 07:51:54 pm ---Looks nice! I might be a bit dense, but how does a "sectional winding" go on the core?
I suppose you do all the windings in this sector, then somehow (how?) fix them to the core, remove the next mold sector rinse & repeat?
If so, are all the sectors then connected in series or individually brought out? And how does the "core hardware holder" fit into the equation?
--- End quote ---
Well, each section is independent of each other. All of the sections are first aligned correctly to the core, and then each section is tightened down with the 4-40 screw and nut. This toroid of the 22 toroids was the shortest height of all of them and if and when I get around to another toroid, I'm thinking of using washers between the top and bottom of the molds to fill the gap.
Regarding the change from one section to the next, on my first sectional mold of 24 sections that I did, I thought this might be a problem. When winding, I would keep constant tension on the wire, and when the next section was due, I kept a small amount of tension on the wire as I removed the next section. After the first turn in the next section, the previous section as essentially locked down. The movement of the wire in the previous section when starting the next section was little, as I remember there may have been movement of only the last turn that may have slipped, but it was easily put back. The key is to always have tension on the wire.
This may not be the case with this new one though because of the smaller width of the sectional winding due to using more sections. I haven't actually started yet, but I'm hoping that the 30 sectional mold will have the same winding characteristics as the 24 sectional mold. I'm also hoping that the added sections will increase the Q.
On a separate note, the molds don't really have a great alignment unless some care is used to make sure the inner smaller top wedge part aligns with the bottom, and that I think if I were going to make more molds in the future, I would include some type of keying of the top and bottom to more easily keep the alignment. Also, the 1/4'' gap I thought was a problem was actually due to how I put the molds on. Basically when the sections were loosely on, they didn't fit perfect but when they were tightened down in the correct position, everything fit together nicely.
The core hardware holder is basically what is going to hold the toroid inductor away from damage, and create connection points for the inductor wire acting as terminals. I've actually thought about changing it a bit by making the center strip a circular piece that has a hole so that later, a cover for the inductor can be bolted on, completely shielding it from damage. These core hardware holders have not been printed yet, as I was going to check the window area dimensions after the core was wound, and adjust this circular piece to fit this dimension.
The hardware holder is really only a prototype, as I'm thinking that it's better to hold onto the core, than the windings. Just typing this actually has my mind already coming up with a better design. (Thanks) Maybe I might include a extra piece that spans across the holder on it's top to reinforce the holder. Anyways, if you have any more question or maybe suggestions I'm up for that.
Lastly, I still haven't come up with a definitive answer if taping the core with a thin layer polyimide tape would help increase the Q of the inductor.
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