Homemade Magnetic Cores! (Part 2)
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- Опубліковано 28 лип 2024
- I've improved my process for making magnetic cores. I found that using solvents instead of heat allowed for easier casting. In the future I intend to experiment with both mechanical and pneumatic pressure to get higher quality parts. Let me know what you think!
- Наука та технологія
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suggestions to improve your parts number one warm your mold before casting, warm part a and part b separately you can use a microwave for this and an infrared thermometer remember the hotter it is the faster it will set. vacuum purge warm resin part a and B check temperature warm again if needed then mix your iron powder with part a before you mix the two parts together ideally you shouldn't need to use a solvent with urethane, viscosity can be adjusted with temperature, when mixing be carful not to get air in the resin, also when pouring your part slowly drizzle the resin down the side of the mold, the idea is to keep one stream of material flowing into the mold try not to stop and start again it needs to be poured all in one go.the part should be poured quickly so that the mold doesnt lose too much heat. then place the poured mold back in the oven for an hour (or longer) take out and demold the part and then reduce heat and place part back in the oven to keep warm overnight to cure. you will need to experiment with temperatures and times as i have only used commercially available urethane and every type has different time and temperatures, oh yeh also using multiple different size of iron particulate will improve density. urethane will shrink slightly so be sure to allow for this.
using this technique i have made parts stronger than steel and with zero air bubbles and even distribution of metallic powder
oh yes making the molds out of a more flexable urethane works really well
Thank you for posting these. You're helping to expand the free knowledge base!
Genial!!! Nunca pensé que fuera tan fácil hacer núcleos de material compuesto para transformadores y bobinas.
Just stumbled on this. Very impressive casting and interesting results.
I've been thinking about this to make shaped 20-40 Khz cores for a single magnetic pulse instead of using expensive laser cut silicon steel laminates. Definitely going to subscribe, good work.
@Benjamin Marshall, I would try using sodiumsilicate as a binding agent. With atmosferic CO2 and water it will become a ceramic substance that is also heat resistant. I don't how hot polyester and polyurethane can get but I presume those adhesives will start to smell and produce toxic fumes when the core gets really hot. Possibly sodiumsilicate as a powder can be mixed with black ironoxide in dry form and when packed in the mould it will absorbe carbonated water (the drink soda water).
Nice video, to improve iron density you can use two or tree different size powder grain .
Little trick for removing the air from your molds, use an engraver and just tape it to the side of your mold it will vibrate and settle your material removing pockets. They do that with Concrete specialized tools
I was thinking about doing exactly that!
Would a small ultrasonic cleaner work? Say add water, close the lid, and place the mold on top?
To isolate the powder, you can mix it with paint, or with a very weak glue. Spread the powder to make a thin layer and wait for it to dry. Then you use any kind of glue to put it all together.
Yeah I was thinking you could hang thin insulators (pieces of plastic or something) in the mold as you fill it to keep the eddy currents down. Your ideas sound very interesting, and we could also try doing that only in thin layers (like do a layer of powder, thin layer of paint, dry, repeat).
The magnetic field will go with the length of the coil and generate currents in the same plane as each individual turn of the coil, so the insulating layers should go in parallel with the coil (vertically in this case) right? So to use your idea in layers we’d just turn the mold sideways. I’m sure any variation of our ideas would make it harder to pour but it might be better or cheaper than the insulated/chemically encapsulated iron powder he mentioned 🤷♂️👍
Exactly was I was looking for.. and even with a scientific approach! Great! Thank you!
Nice video! Ive been playing around with this before aswell but only using polyester. Im going to try to either press, sinter or fuse dry powders next time I try. I feel like directing some current either around or through the mix together with pressure could produce some very good and interesting materials
Maybe take the iron powder and put a slight food oil coating on it, then heat it in the oven to result in a carbon coating.
Decent video. Under appreciated for sure.
Brother, you are amazing...Go ahead and I wish you success from my heart ✌
Perhaps try looking into "Metglas" powder. That stuff has the highest permeability of all metals, also expensive. It is man made and specifically engineered for making strong transformers. "Metglas" cores are used in professional applications in transformer designs. I was planning to mix and impregnate Metglas powder into 3D printer filaments, so that I can 3D print magnetic cores for transformers. It will be much more easier and provide more accurate complex shapes of core prototypes and designs.
Metglas does not come in powder form. It comes in foil. But you can get atomized 99.9% iron powder for cheap. It is nearly the same as Metglas but easier to form and without the high expense.
@@dee5556 you’re crazy, pure iron will never be same as to metglas stats. Metglas has a permeability of 100,000 when pure iron has 5,000. Powdered metglas could be accomplished if you’re smart and have the funds.
Great experiment 👍
It would have been great to compare against a core from laminated sheet metal (iron).
that's really interesting research, and well done!! but... apparently... my silly goal of making an elongated core for a stupid TV flyback seems vain, i have to try to crack some of those as better as possible and frankenstein together the pieces until they close, luckily an air gap is needed, so the imperfections would work as air gap themselves (kinda)... i also saw an old video of a literal "structure" of flyback cores put together to make a single giant core, without breaking em, but it has a crappy shape
There exist a ferro like resin for SLA 3d printing. It's called ferrolite. Would be interessting to see some cores made of it. For me in personal it's way to expensive.
Dude this is really cool! I have a bunch of thoughts, mostly around other additives that could be in the real ferrite. Did you ever get a chance to try Mica powder? Its a pretty common resin addin, its super cheap, and has high thermal conductivity (which could keep the ferrite cool) but low electrical conductivity.
Cool vidio. I want to see how the workpiece is formed in the vacuum chamber. And it would be cool to protest the magnetic characteristics of such a material.
Excellent stuff. Have you tried grinding the powder down even finer. Maybe use an old coffee grinder ?
How about making a hard mold and pressing the powder into place?
Or use really low resin concentration (or something like tung or linseed oil) so it holds but is mostly a paste and then sinter it, or use a layer of resin on top to hold it together.
Using a mortar and pestle to mix this type of aggregate (wetted powder) works well.
Though as you said, it might not help.
have you though of using vacuum chamber to pull all the air out of the polyurethane and/or thinned self leveling 2 part epoxy...mix the metal in, vacuum it to remove the air, then pour into mold, and re-vacuum to see if it will draw into the mold better
Never made molds but I have seen people on YT vacuum down the mix and it really helps mold
Ooh...maybe a vibratory bed to help it settle better as well...I think vacuuming it down would help
Superb bro..
I am a big fan of you..
Keep going..
Your support truly means a lot to me. Thank you!
So great master, please what can be the effects If I don't use axitant for my own experiment
You are the best just continue
Thank you for your words of encouragement. I just make these videos to document what I build, but it's nice to know people enjoy them.
Really great experiment. Given the outrageous price tag of large iron powder cores (I suspect that the reason is the strict adherence to the published material specifications for the final product making the production process quite hard and maybe factory rejects of cores that are subpar quality), making DIY cores seems a reasonable option. I wonder if any industrial process use a cold process with solvents and binders or if all of them use heat and/or pressure (sintering process). For your specific process, I wonder if the iron powder may settle down with gravity if the solvent/binder mix is not too thick during the long curing time, giving rise to uneven distribution of the iron powder in the core. But by the look of your final product, it seems quite homogenous. Using iron carbonyl could be a nice refinement, If there are no unwanted chemical reactions with the solvent or binder. Maybe an organic chemist could chime in. Also, you could make yourself a BH curve analysis circuit to plug into the oscilloscope for further characterisation of your cores. Have a nice day!
very nice and interesting
There’s a really runny resin used for firming-up soft wood. (?)
Perhaps mix the resinous materials separately, (using a really slow-curing resin) and then mix them and press the mix in a warmed mold under a hydraulic press??
Thanks for doing this. I was wondering how to do *generator* cores.
Using the terms "iron powder" and "ferrite" interchangeably is a mistake. In RF work, iron powder cores start outperforming ferrites in the low-to-mid-HF range. I don't know what difference it makes in transformers, which are typically kept well under the HF range, like about 1MHz and below. The primary difference between magnetite and iron is that magnetite is made primarily from iron oxides, while iron powder is metallic iron. The so-called commercial ferrite core most likely uses a powdered alloy that is tailored to the desired characteristics. Maybe some silicon would help there - it certainly does in sheet iron transformer cores. I think that powdered-iron formulas are closely-held secrets among makers of transformer coils. I remember TDK using Sendust to make magnetic tape heads, due to its very high permeability and very high saturation flux density. According to Wikipedia, Sendust is typically 85% iron, 9% silicon, and 6% aluminum, but again, there are trade secrets involved. And how the heck to you get the powder?
Also, I don't think the conductivity between particles is affecting your inductance that much. More likely it will just result in the core operating slightly less efficiently, and therefore heating up a little more for a given power. Eddy currents become a problem in the ohms and milliohms ranges, much less so in the hundreds or thousands of ohms.
Finally, your urethane/iron slurry still looks pretty thin at 80% iron, and I think it would be worthwhile to see if it DOES make a difference going to 90%. I would worry that the iron is settling out of suspension, leaving the density of iron lower at the top, especially with the long cure time you've chosen. Because of this, I would think that overfilling the mold even more, then running it through a band saw or just grinding it down before the urethane gets too hard, would give better permeability through the whole core.
How about mixing the iron powder with Smooth-On 2-part silicone, instead? Would allow the core to be flexible. Just a thought!
How well do they handle heat? I've been using things like black iron oxide , gypsum, plaster of Paris, dipped in resin for a step down. The humming of the transformer, with the turn ratio I had, sounded like thunder rolling, it was scary
Any details on the ferrite core you're comparing it to? Do you know what it's initial permeability is supposed to be?
Have you thought of using water glass as a binder when cured it is very hard like glass and can be sintered or cured with C02 dry ice.
جرب هذه التركيبة راتنج لجمع المكونات
سيلوكسان واحد، وسيلان واحد، وهاليد معدني واحد، وألكوكسيد فلز واحد و/أو جسيمات نانوية من أكسيد الفلز كجزء أساسي من عامل الربط
If you got good result out of simply filling a 3d printed cylinder, would be worth it to try to make a actual core as a vase mode print on a 3d printer and simply fill it with iron powder? How bad would it be in comparison of a "molded" home made one? I would love to see that tested.
are you still working with ferite cores?
from paper titled "Manufacturing Processes for Permanent Magnets: Part I" (from Springer) :
_After calcination, the block is wet milled to powders with an average particle size in the range of 0.7-0.9 lm. Particle sizes < 0.7 lm create problems in compaction and sintering, while particles> 0.9 lm affects coercivity_
what size of the particles did you make? because that affects the performance of the magnet
Can you make a motor spinning just using a ferrite core materials an what are the result like pulling energy or what.
Can you try this with epoxy resin
Sir g EE 28.no.ki core home made kese bnaye matreal nam btav pl.
Excellent! exactly what I was looking for thank you, you have saved me so much headache, I was about to go down the iron pla route but then actually read the properties so have been searching for castable transformer core material, there is nothing out there, well not that you can get hold of anyway.
So my goal is a single rotor axial flux motor that the rotor is incorporated into the base of a centrifugal fan with the stator underneath. (large model RC hovercraft)
Considered air core however they will not self start with sensorless esc's and have such low torque and high rpm, the opposite to what I need. what I do need is a axial stator with back flux return path / top shoes and a strong rotor magnet array with 'backing iron' for the lowest kv I can get with one rotor.
Now I can model the motor with a castable stator in mind :)
I do have 2 questions if I may?
with the 90% iron cast stator dose your motor have enough feed back to self start with standard RC esc's? I wasn't sure if the laser was just for the scope or timing as well.
with the carbonyl iron I know you did say there was no real gain to inductance but how about the conductivity?
nice work BTW!
I'm sorry, I just now saw this comment. I would love for you to hit me up on facebook or discord to talk about your project.
I was in a similar boat looking for cast-able stator materials, and there is almost no information out there. So I decided to make some!
As for your questions:
I've tried to test my home-made motor with a standard sensorless ESC, and it did not want to start. The lasers ARE being used as sensors for my psuedo-ESC circuit. Though mind you, my home made motor uses a much less refined recipe for the stator. I know I said it was %80 iron powder by weight in the motor video, but it was more like %50 MAGNETITE powder by weight. Using a stator of %80-90 iron powder should be significantly better, and I don't see why it wouldn't generate enough feedback to self-start.
As for inductance vs conductivity, I hadn't thought to test that for the carbonyl core until you mentioned it, and I just tested it by touching my mutlimeter to two of the cores with about 1cm separating the probes:
An %80 iron powder core read 2-3 k-ohms.
The 90% "Carbonyl powder" core read around 30 ohms, so it's obviously much more conductive.
I'm thinking that this means the carbony iron powder I purchased is in fact not genuine and is just extremely fine iron powder, which would also explain why it APPEARS to have the same inductance. The finer powder & higher concentration is probably resulting in eddy-current losses that lowers the apparent inductance, despite the core likely having a higher permeability.
I did read a paper a while ago that talked about mixing iron powder with a low concentration of resin and magnetite powder, letting it cure, and then re-grinding it down into powder and mixing it with resin again to cast magnetic cores. I guess the idea was to coat the conductive iron particles with non-conductive magnetite, thereby preventing said eddy-currents.
@@BenjaminMarshallScienceMan no worries man! Thank you for your detailed reply.
I was wondering about the carbonyl iron powder, I don't know if this is the case for you but from what I have found carbonyl iron powder as manufactured dose not have a insulating layer, they are just micro spheres of iron. Insulated carbonyl iron powder, is a extra stage of processing that is very hard to get / very expensive.
I found information on different methods of adding a insulating foreign oxide layer to iron powder, industrial method is out of reach, some were wet chemical. Then there was one tbat simply heated the carbonyl iron powder on a stainless tray in a semi dry oven at 200°c for 2hr, that was proven to give a micro layer of even iron oxide, but no tests on conductivity afterwards. This method may well be worth a try, if I get there I'll hit you up forsure!
Thanks agane.
I just made a comment that you might be interested in. We are working on similar projects. Its not too hard to make your own circuit and PCB design. I used instrumentation amplifiers and photo diodes with a 3D printed commutator. I also incorporated geared stepper motor and printed gears to move the commutator plate for an auto advance. One of the amp channels can double as a tack signal to a micro-controller for RPM and auto adjustment to the advance position. This of course is not for a finished project design but for prototyping and testing it will help generate the numbers you need. The micro-controller can also feed data to your computer in combination with a dynamometer for performance statistics.
I’m interested in self-winding a toroidal core for a DIY 48v x 10KW, 240v 60 Hz, two phase inverter. Any idea how your material would work in that situation?
I’ve been watching a lot of DIY toroidal transformer videos from SE Asia, being used for power amps for monster audio systems. I know some of them would be interested too.
carbonyl is use in high frequency applications. For motor cores you need the highest B curve an lowest H curve with the highest electrical resistance possible. 99.9% pure 50-50 iron cobalt alloy has the highest magnetic flux density and very high perm. A lower cost solution is 99.9% or better 99.99% iron powder. 99% is better than lower % but has significantly lower property values than 99.9%. Permeability of iron powder increases exponentially with purity. For DIY use the highest dielectric epoxy you can find 500-800 v/mil with a reasonably low viscosity. Mix into a thick putty and press into a mold as densely as possible. If electrical resistance is still too low mix in a bit of iron oxide 3. Don't forget that motors are low frequency. 20k rpm motor is firing coils at less than 1 Khz.
Very helpful experiments! Could you please share the link of the iron powder you used.. And what's the mesh value BTW?
bit.ly/2Q3MTBD This is the powder I used in the video, it's 325 mesh.
Though I've noticed finer powders being able to be mixed in higher concentrations. I was easily able to make a %90 pure mixture with finer powder, but the 325 mesh came out clumpy at %90 concentration.
@@BenjaminMarshallScienceMan Thanks . Does the casted stator turns out stiff or kinda flexible or brittle at the end?
I haven't tried it yet but i think the higher mesh value of the iron.. the less stiff the cast will be. Maybe i am wrong .
I also see two types of powders online... Black iron oxide and just iron powder.. have you tried both?
Even the %90 pure cores I've made with very fine powder I would describe as 'brittle'.
They have SLIGHTLY more flex than real ferrite (which is essentially a ceramic) but they don't break easily, and when they do they fracture instead of bend or tear.
ارجو ان تخبرنى بجمل بسيطة محدده اى راتنج اعطى افضل نتيجة او افضل اداء .... و كم نسب اكيسد الحديد الى الاضافات الاخرى فى تجربتك .... لانى اريد تنفيذ امر مشابه عندى .... اشكرك
Have you tried mixing the iron powder into some ABS slurry/paste (from failed parts)? If that were possible, it would greatly decrease the cost of the magnetics since you wouldnt have to buy the resin and ABS filament is quite cheap.
I haven't tried that, but I feel like ABS wouldn't be able to accept as much iron powder as resin can.
My most recent parts have been %90 carbonyl iron powder.
@@BenjaminMarshallScienceMan Don't bother doing it, there are already few iron powdered filaments that are being told online, they put a lot of iron powder into the filament and many people have tried making transformers out of them, with no good results. Try using Metglas powder.
@@ShopperPlugGood luck finding metglas powder, if a source for it even exists for us mere mortals it would be extremely expensive.
As a reference metglas brazing foil can be had for the low low price of $1600/kg
@@BenjaminMarshallScienceMan I'm interested in seeing your test results with the 90% carbonyl iron powder!
I realize I'm coming into the discussion late, but I was wondering. When a piece of resin and powder doesn't work out, where do you throw it. Does it go into regular garbage, or the recycle bin?
You're not likely to find anybody willing and able to recycle it! What you've got there is a composite material, and there's very little if any recycling of composites being done.
Conceivably, could you pour you resin in a magnetic field to align the iron properly?
Wouldn't that draw all the particles to the surfaces ?
could you instead make sheets of resin with iron core... that way stack them up with insulation and check their magnetic flux density? you could also instead make a 3d print with tiny slots in it and fill it with iron powder. it should easily reduce eddy current losses without compromising your build process for different shapes and sizes-this is in comparison with you filling an entire cylinder with iron powder able to conduct the entire volume, instead printing multiple discs within the cylinder with no conduction between them and filling such slots with full iron powder would in theory get you much better result. varying the slot thickness would probably impact the B-H curve and also electrical resistance. so its got design parameters to tweak! would love to see the result of such an attempt! Thank you for your contributions anyways!
The thing that limits how high a frequency you can go with laminated silicon-iron, is that the eddy currents start to happen within the layers, so you need an ever-greater number of ever-thinner layers, resulting in a less dense core. The whole point of using powdered iron alloy or ferrite cores is that the grains are small enough that there is very little path for eddy currents to follow, as long as the grains can be insulated from each other. With ferrites, the grains are already pretty poor conductors, and with iron powders, you use an insulating binder. I think Benjamin's idea of using a powder that includes an insulated coating is the ideal approach.
it does not matter if its not smooth but pearmeability matters. now, relate it to material science n u get d alien gud stuff.
Polyvinyl Alcohol and your metal mixtures and mix it . Add borax whenever you want it to harden .
If/when you're back safe&sane why don't you try to slowly heat degreased metal powder spread onto metal sheet till it gets dark violet/black coloured and cool it down instantly in any oil. Wash oil off with alcohol/degreaser. This would be what you was looking for.
good
I hope you revisit this topic as you were onto a great concept. Your method is flawed for producing high density cores. First make a proper mold and use mold release compound or 3D print a liner out of dissolvable support material. To make 3D printed parts fit snug make the inner part 0.1 - 0.15 mm smaller. For tight press fit 0.05 mm. Then either use high vacuum bagging or mix slow cure low viscosity high dielectric epoxy 500V/mil + and hardener (There is a good one on Amazon for cheap). Then knead in fine Fer-rite powder mix of your choice till you get a firm putty in which you cold press into the mold. For complex geometry you need to make a custom plunger tool to fit tight with some channels to allow air to pass in/out. I use a vise to pack with the tool. 3D printed molds need to be SOLID FILL. You can't use just any fer-rite or any epoxy and expect a good result. For motor cores you need a high B and low H but permeability is not as much a concern. 99.9% pure iron powder of 300 mesh is a great material. Add some iron oxide powder to increase dielectric strength and decrease H without lowering B curve too much. This will give a mix that will give great B and H as well as decent permeability. For High power motors use 99.9% pure Iron Cobalt 50-50 alloy 300 mesh powder instead of pure iron powder. You can also mix and match powder ratios to get the best material properties for your project requirements. This is never going to be as high quality as powders engineered with oxide layers and other specific properties pressed and sintered and annealed but it will give a good material for prototyping concepts or DIY designs.
Update... I'm using Max Cast hybrid epoxy casting resin 510V/mil dielectric mixed 30g of epoxy to 280g pure iron powder. Its very dry but sticks to itself like a sand castle. The 3D printed mold needs to be in pieces with breaks in all the corners so that it comes apart and is bolted together. No trapped faces. It will not slide out. One side open to fill and pack. I'm using Mann ease release 300. weigh the iron powder into one cup. Mix epoxy in another. Slowly incorporate the iron powder making sure to mix it well. Make sure it is consistently mixed, then pack into mold as hard as you can. Then place mold in a pressure pot up to 5.3 BAR or 80 PSI. This makes the densest material with a resistance of 500 Kohm/cm 2.6 Mohm as measured in the video
@@dee5556 Does the pressure not compromise it by trapping the gasses in it? I always try to cure epoxies under vacuum because it off-gasses so much.
Have you tried using ferrite powder? Ferrite uses iron oxide/rust and maybe you will get closer to the real thing with that. For small parts it shouldn't be too hard to build a tiny oven out of nichrome wire, 2-4 fire bricks and a 10A relay. Total cost shouldn't be more than $40 for the size parts you are making. That would allow you to sinter your own ferrite ceramic cores.
The magnetite powder I used is iron oxide, Fe3O4 if I'm not mistaken. Are you referring to something different? Googling 'ferrite powder' doesn't yield any results where I can buy something I haven't already tried.
Sintering my own cores is an interesting idea.
@@BenjaminMarshallScienceMan ferrite for magnets and cores is a mix (magnetite is an example of that). I cut and pasted the section from wiki below. Soft ferrite is for inductors while hard ferrite is used in motors and permanent magnets.
"A ferrite is a ceramic material made by mixing and firing large proportions of iron(III) oxide (Fe2O3, rust) blended with small proportions of one or more additional metallic elements, such as strontium, barium, manganese, nickel, and zinc.[1] They are ferrimagnetic, meaning they can be magnetized or attracted to a magnet. Unlike other ferromagnetic materials, most ferrites are not electrically conductive, making them useful in applications like magnetic cores for transformers to suppress eddy currents.[2] Ferrites can be divided into two families based on their resistance to being demagnetized (magnetic coercivity).
Hard ferrites have high coercivity, so are difficult to demagnetize. They are used to make permanent magnets for applications such as refrigerator magnets, loudspeakers, and small electric motors.
Soft ferrites have low coercivity, so they easily change their magnetization and act as conductors of magnetic fields. They are used in the electronics industry to make efficient magnetic cores called ferrite cores for high-frequency inductors, transformers and antennas, and in various microwave components."
4:37 I think it is because of the weight by Dividing the Weight you are reducing Its real power in % example ferrite 25g vs the one you created 12.8g is -50% all this regardless of the perfect shape the material has is what does the magic
Did you get around to try the insulated iron powder? Do you think epoxy resin would work better?
Also, you mentioned 3d printing with iron filled filament. Have you tested how good/bad that was, compared to the castings you made?
I used the carbonyl iron powder. It was so fine that the polyurethane resin was happy to accept a 9:1 mixture (so %90 metal powder by weight). Despite this, the resulting core was at best only marginally better. Using the same 50-turn coil I only got a couple microhenries higher inductance. So I decided to not even bother making a video about it. I do have a plan to use mechanical pressure and metal dies to get better casts, but I've been waiting on my CNC mill to arrive before I attempt that.
Epoxy resin could work, provided that it has a low enough viscosity to accept a large amount of powder. But the type of resin you use will do nothing to directly improve inductance.
As for magnetic filament, its magnetic permeability is atrocious. If I recall correctly its relative permeability is about 2 (The worst ferrites are about 40, for comparison.). It would be better than an air core, but I'd only suggest using it if you have no other means to build something better. It's more of a novelty filament in my eyes.
@@BenjaminMarshallScienceMan Very interesting. I mention the PLA iron filament because I saw someone make a brushless motor with a printed stator core on UA-cam. So it was basically like an air core...
A motor with a stator core made from magnetic filament or just plain pla will LOOK like a very successful motor. But motors with lower inductance coils will actually have a higher RPM but almost no torque.
I did actually make a motor using the magnetic filament, it's the last motor in this video:
ua-cam.com/video/wknisHshDzQ/v-deo.html
You'll see that it actually has a very high RPM, but stalls out after a while because of how little torque it produces. Compare that to my most recent motor here:
ua-cam.com/video/la4pkVB2tqg/v-deo.html
That one uses my less refined method of making homemade ferrite. It's RPM is noticeably lower, but it produces a lot more torque.
These are iron powdered cores. Why not compare them with the yellow/white cores? Comparing with ferrite is like apples and oranges. Mix in ceramic filler powder to increase the resistance.
Powdered iron cores should have a higher inductance than ferrite though.
Do you think that increasing the resistance would also increase inductance through reduction of eddy currents?
@@BenjaminMarshallScienceMan powdered iron cores have significantly lower permeability and AL value than ferrite. Their advantage is that their saturation current is much higher without a gap.
Nice work
Real ferrite is densified under hydraulic pressure and sintered.
That's why you will never attain that densification with poly casting.
Look up the PZT transducer manufacturing process, same thing.
Nice video. I would recommend checking out the epoxy videos on the Technology Ingredients channel for a bunch of expert epoxy advise.
Can I have your contact no I am trying to Make ferrite cor pls help me