ฝัง
- เผยแพร่เมื่อ 9 พ.ค. 2024
- So I built technically my life's second electric motor. An Axial Flux BLDC motor. Could you use it for something useful? I'm sure it'd do okay as a blender motor or something... Unfortunately I could not test out the motor quite properly, as I believe it would be even more efficient at a higher voltage... none-the-less, it works, not too bad, even. Next time I will also actually put thought into the real electrical design of the motor, as this one was just for fun and a basic learning experience before, one day hopefully taking on the project of making a useful electric motor with more seriousness. (For example a DIY electric bike motor)
Link to mechanical counter page on thingiverse
www.thingiverse.com/thing:516...
Music from TH-cam Music Library
Chapters:
0:00 Intro
0:28 Motor Types
0:52 BLDC Motor
1:22 Axial Flux vs. Radial Flux
2:15 Basic Motor Structure
3:21 Motor Build Start
3:35 Rotors
3:42 Magnet Back Iron
4:07 Rotor Build Continues
3:39 Halbach Array
5:00 Stator and Coils
5:52 Wye Configuration
6:38 Finishing the Build
7:24 Controlling the Motor
9:10 First Power Up
9:53 Modifying the Bearings
10:26 A Glint of Success!
10:52 Motor Kv
12:14 Motor Efficiency
13:22 Max RPM
14:04 Motor Weight
14:25 Closing Words and Thank You for Watching - วิทยาศาสตร์และเทคโนโลยี
I tried to fix the motor's Kv rating after the video went live, as I had some ideas on what could be the reason for phase A being broke (I figured that maybe I had somehow connected a coil in phase A backwards or wound one coil backwards... somehow)... however, nothing I did helped... so I still do not quite know what caused such a big difference in phase A as opposed to B and C...
I will not make the stl files public for this motor because it's overcomplicated, there's no assembly instructions and it only works properly on low power... if you push it too hard, it will melt.
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Did you measure the resistance of the phases? it is possible that maybe there's a short in one of the coils.
@@RoycoNL The resistance of the phases is the same as far as my multimeter can tell (0.1ohm resolution).
Hey, is there any way I could reach you? (E-mail, discord, Instagram...) Maybe my team could help you.
It may be short-circuit in one of phase coils or some issues with coil winding resistance (some wire conductivity imperfections or such). Just my guessing.
So anyway it is an interesting video, thank you )
You're the most comprehensive explanation and hans on on these type of motors. Thank you very much. I like your style. Keep making more of these. Best vibes 👍🏼💯
I have wanted to try this for years. Thanks for recording your journey and sharing with us. Much appreciated ;-)
Good job! Not bad for your first made-from-scratch moter, not bad at all! Looking forward to seeing more of your work.
This is an amazing design. Should be super proud of your work. I've only just started 3D modelling and I am in awe. You should consider putting this up on a modelling share platform. Something like onshape where you might get engineers at a similar level that can make tweeks. If it goes to thingyverse it will get bastardized
Thanks! Why I don't really want to release the 3d files is because the motor requires quite a bit of other "stuff" as well to work (the washers, magnets, wire, bearings, shaft, etc...); so for anyone to really be able to replicate it, I would certainly have to make a proper manual for it. I think this particular design is not quite worth the time making such a manual. Whenever I get to making the next motor however, I will also make an assembly manual and definitely release any files :)
Well reasoned. I was going to ask a similar question but instead I’ll wait for the next impressive motor you come up with :)
I love the shots of the motor-winding machines, thanks!
Just found this gem of a channel.
Making motors, and compute shaders?! Awesome
This is a very impressive piece of work. This design is also my favoured concept for a BLDC motor. Regarding the phase imbalance you experienced, a fairly common cause for this condition is a difference in strength between the magnets. Generic magnets, although rated by suppliers as say, N52, tend to vary quite considerably in strength.
I once had a similar issue which I fixed by constructing a simple device, consisting of a wire pointer which pivoted on an axle. One end of the pointer has a steel washer soldered to it and attached to a coil spring. The contraption works much like a pressure gauge, the more pressure you apply to the sprung side of the pointer the more the opposite end of the pointer needle deflects. I put a simple linear scale under the arc of the pointer.
Now, using this device, place one magnet from your batch of magnets close to the steel washed end of the pointer, at a proximity that gives about a 45° deflection. Note the reading and mark the magnet. Check all the magnets by placing them in the same spot and orientation, record the deflection force and mark each one. I found significant force differences between many of the magnets, however, I had a lot more than I needed so was able to put a requirement together with almost exactly the same strength. This did solve the issues I was experiencing with a prototype project.
There is one other condition that causes phase imbalance in much the same way, and that is the distance between magnets, and electromagnets'. Even small variations here can cause significant differences in efficiency between phases. This distance or gap, the smaller it is, the more efficient the motor will be, as defined by the "Law of inverse squares" - The force that magnetic poles attract or repel each other is proportional to the inverse square of the distance between them.
I have seen a motor of this design that had an efficiency of 98%. It was very well designed with four magnet rotor discs and five air core coil discs. The whole construction was made from high precision machined aluminium with a micro gap between the magnets and coils. The N52 magnets were built to order and the coils wound in precise layers with square, enamelled copper magnet wire. The interesting thing about this motor was that each rotor had six round magnets and six air coils of the same triangular shape as shown in this video. The only steel parts were the long screws holding the whole aluminium assembly together, so it was incredibly lightweight too.
Thank you again for a great, well done video.
This is awesome. ive been thinking of making something like this (among a bunch of other things im always thinking about) so definitely cool to see one working already!
I learned a lot through this video, that I don't from dosens of other videos.
Many other available videos on youtube only for entertainment purpose, but no one tells about current flow and coil turns and thickness and efficient of motor.
Well explained video and informative too. 👍
This test at 10:41 really shows how effective this motor is. You'll accomplished a great feat of engineering. Thank you for your work.
I wonder if the halbach array was the key
Loudspeakers contain soft iron rings perfect for this application.
This is awesome, Ive been doing CAD for around 2 years now and I wish solid professor would teach me how to design something like this. well done. While their are problems with it, that is simply a natural part of the design process. Super cool and keep it up.
Also, that "chinesium" joke gave me a good chuckle.
Amazing work!! And nice design.
omg lol this is so legit. I went and watched your whole channel after this! So good! I made a pmdc motor years ago and you'd get a kick out of how terrible some of the CAD choices I made were (threads mainly). Reading the comments it clicks that everyone wants the CAD files but- idk I'd hold onto them cause you do 6 fig work here and I wish you the quickest path to it. I get that certain design and hardware choices that are regularly unique to a project and that there are regularly more efficient ideas people have came up with over the years but you're not on the wrong side of that coin here. So funny you hit all the barriers I ran into on the head w heat and PLA parts, doing it anyway, the lithium batteries > alkaline- the current limit w alkaline was the curiosity that had lead me to 'lemon batteries' during my motor build so the video on potato batteries was an absolute gem. Where I love electronics, I found that mechanical coupling and little details are regularly the hardest part (the least flashy parts) and the electronic and flashy parts are hard to nail for reference. Can't tell you how absolutely floored I was to see that winding mechanism- so clever- mine was a tally sheet plagued w question marks. A lot of things come to mind w the starting issue you had but it'd be more than I have/will written/write to go over all of them. Your efficiency is killer; considering we're working w 3D printed chassis, anything that gets above 2k rpm and difficult to hand stall w out melting the thing is a work of art. You've likely done a fair amount of testing and probably know best here but if you have the budget in heat, you might play w inductive/capacitive loads in parallel and see what that does for your power factor/efficiency, and series resistance might actually help your starting characteristics (seems like a transient issue causing the flux to lap the pm rotors). You've probably done all you can on the starting sequence frequency but that can be tricky to optimize sometimes. Anyways- so good- so so good; please keep doing what you're doing, and I'll be on the look out for a patreon link.
this guy is so underrated i hope his channel grows and becomes one of the og's
great project and workmanship
Amazing project with very insightful information thank you.
That exploded view animation looks incredible.
Nice build! I have made some powerful iron less motors over the years, 30,000 rpm from 8 magnetic pols with 24 coil poles, and a 69,000 rpm from 2 magnetic poles with 6 coil poles. If you want more power from your motor, unwind your coils and use the same wire but cut it into 3 lengths so it’s triple wound. And get a more powerful ESC.
Hi. RPM does not necessarily mean higher power. Power = distance (RPM) * torque. This motor has a low kV (low rotation speed) but a high torque instead. Next year I might want to try making an e-bike motor, and e-bike motors need to have a lot of torque but lower RPM. The ESC plays little role here - it will give you enough power until it burns itself or shuts itself off completely to protect itself, neither of which happened here. I now have a sensored ESC for my next motor project though, and that would increase the performance of the motor a little bit as well, if it had hall effect sensors fitted.
I enjoyed your video dude. Most builders are using PCB multi-layered coils for efficiency. Thanks for your efforts.
Very cool idea and a really nice execution!
Epic design and video
Great work, keep it up!
Great video and big respect. AND Nice of your sister to do all the hand modelling for you. 😉
Excellent work!
amazing execution!
Thanks Birdbrain!
Here's a project idea I'm also bugling on, but you might be interested as well:
Take a bicycle rim, attach a circular plate on the spokes, and use axial flux to drive the rim.
woah, nice design! you need more subs!
Great Job!
Great video, keep up the good work. Your channel will grow
It makes a really nice sound as well. Loved the video, super interesting!
Yeah, I was actually quite surprised that the sound did give a real feel of a V2 haha.
@@BirdbrainEngineer Put a gearbox on it and you could make a good sounding electric car like this one: th-cam.com/video/YJ0CU0-PzQc/w-d-xo.html
@@swecreations Also whoops, I replied to it from my comments tab from youtube studio, and I misjudged the video this comment was made on - thought it was on the V2 air engine video haha
@@BirdbrainEngineer Look at the video I linked still though, I think you'll find it interesting
@@swecreations I did, sounds wicked!
cool project man!
Excelente trabajo, aprendí bastante con su proyecto muchas gracias por compartirlo. Saludos cordiales.
awesome skills, thx!
Nice video, thanks for sharing it :)
I wonder if there is some way to improve efficiency by including the Tesla turbine into the design of an electric motor using the rotation to collect air and using the rotors as the turbine disks . In turn also cooling the motor for better rpm output? The only issue would be the GeForce of the turbine design which even Tesla himself could not solve. His turbine works with liquid and gas.
Great exercise!!!
The only problem in this motor masterpiece is that my boy didn’t count for bigger bearings, small bearings will just be eaten up by the rotaforce.
you should’ve used a 15mm ID bearing, better and more powerful ESC (40AH), metal casts in these size motors are mostly aluminium, nearly 350-800 watt **%80-95** efficiency.
Why?
Ans: SHOCK absorber
Also make sure that the carbon steel on that thing is completely isolated from the windings.
The plastic in this project’s displace’s the magnet position due to rotation, and drive’s it to a position where it shouldn’t be from from a position where it is, so the small change in position of these magnet will make the motor guidance system to send more POWER which will eventually deep fry your brunette magnets(coils) and your motor guidance system(maybe)
If these steps were taken seriously, the efficiency would’ve gone %75 and above
Aah, the motor was never meant for anything but learning and demonstration of working principle... I would have to do a lot more research into manufacturing if I wanted to make something that would be a useful prototype... maybe some day.
Good job 👌✌
thanks for the video.
great video... pls can you explain how you arranged the magnets in hallbach array?
You deserve more subs
Very cool!
nice build.
thanks for the video
Suggestion for your next motor, is a hollow core, of the type used in robotics. So wires can pass through where the shaft would go.
The advantage that axial motors have over radial is the unused length of magnetic flux path is much much shorter. In a radial motor the flux needs to travel around the outside of the motor, whereas in an axial motor its just a short hop from one coil to the next.
Your design takes this a step further by using a Halberg arrangement.
One improvement, again on the magnetic flux path, would be iron cores for the coils.
Iron cores for the coils lead to problems with cogging. I also think it is a problem to combine the Halbach design with a backplate. For a Halbach design there is also too much space between the magnets. I guess the use of the normal switched polarity magnets in combination with backplates should work best. In this case it is also easy to calculate the flux density, because the air gap mainly determines the parameters of the magnetic circuit.
Excellent explanation and video to show experimenting w motors. Perhaps if you measure the resistance of the three coils, as installed w all connections, you may see a different resistance in phase A. Pls use a 4 wire meter to measure very accurately. The next possibility would be the inductance of each winding, using inductance meter. Great job
Yeah, I'd like to measure the inductance... still haven't gotten myself to buy a compatible multimeter or something more specialized for that.
All the phase-pairs measured 0.7ohm if memory serves... Would a... say 0.1ohm difference between phase-pairs cause that great of a difference in kv? Should look into that... the actual underlying math looked kinda complicated on the surface though, not gonna' lie haha.
Props to you for measuring the performance of your motor! Instead of a Prony brake, you might consider pumping water as a means of loading the motor, a classic technique. (You control the load by increasing the "head" of the water. The pumped water warms as you proceed.)
Love the music.
10:00 we used to do this with our skate bearings back in the 90's
Very good Project congratulation;)
Impressive. You may want to check the resistance prior to soldering of the coils with and without a magnet over them ( stationary and known pole direction ) to ensure their resistance is close to each other. The magnet is to ensure that any back EMF from the magnet during resistance check can be accounted for as well as any accidental change of winding ends during assembly as a known voltage will result as you remove the magnet.
Very good 👍
hey man great work here! where can i find the stl files for this motor? is it possible to have them?
Awesome.
Just want to point out, all dc motors are commutated. 0:57
While brushed dc motors are mechanically commutated with the brushes switching current through various coils, brushless dc motors are simply electrically commutated with mosfet switches controlling the current to various coils.
Great explanation and to all those tinkerers out there believe it or not I was able to use Tinkercad to make a motor similar to this.
I really appreciate you sharing with us. The amount of detail was pretty good. Testing for KV, efficiency and torque was quite thorough. Thank you
I wonder if the voltage discrepancy in the phases is caused by warping of the stator/rotor assembly? Not sure which, but in that last clip you can see it moving up and down as it spins; that alternation in the proximity of the rotor and stator could account for the voltage difference perhaps? If you were able to replicate a similar machine turned on a lathe or CNC, perhaps it would make the difference? It also looks as though the shaft spins a little faster at one point of each revolution, so that could indicate this issue too
Anyway, fantastic creation and really good video.
The solid steel core (big washer) was a mistake. You do not need a core between the magnets. You can use a single magnet for each pole, no need to stack them. A core associated with each coil can work good but you don't want solid steel. Better to use high silicon steel laminate. Notice how a microwave transformer is made, with layers of lacquer insulated steel sheets? This controls eddy currents but passes magnetic flux. However a fairly efficient motor can be made with coreless coils. A laminated annular casing can also be used to complete the path of magnetic flux generated by the coils.
DIY axial flux BLDC/PMAC motors that test at efficiency levels in the high 80's or even low 90's are not unheard of. There is no reason why a DIY motor cannot match the performance of a commercially available motor such as those made by Motenergy, for example.
Another improvement in efficiency is instead of using back EMF, use an array of Hall Effect sensors for rotor positional input to the controller. You can experiment with timing by rotating the sensor array about the axis of the motor.
You are wasting significant energy by using very flexible 3D printed parts. You want high rigidity and low eddy current losses which dissapates as heat and kinetic energy in the form of vibration and noise.
I would also incorporate a thrust bearing to keep the rotor centered between the stators. This is particularly useful when directly driving a propeller and generating an axial force on the shaft.
There are formulae for calculating number of turns in the coils, etc for different speed and torque requirements for different loads and different voltages. For the DIY-er it is probably easier to simply experiment, and optimize. Another factor for optimization is spacing between rotor and stators.
Hi!
The solid steel washers are not "cores" but "back-irons", which serve to give the unexposed permanent magnet poles an easier flux paths between one-another, which in turn slightly increases the magnetic force exhibited by the permanent magnets. The magnetic flux generated by the electromagnets is not able to influence the back-iron due to the permanent magnets and their much more dense magnetic flux being in the way. Therefore, the back-iron does not experience any eddy currents (there are no *changing* magnetic fields inside the back-irons) and cause little-to-no drop in efficiency. Yes, a back-iron is less needed in a Halbach array rotor, so it *may* have been better to not have it but it certainly would not have been a significant difference either way.
Have you ever tried finding electrical steel laminations for sale? Especially for your specific project? Electrical steel laminations are for products that actually end up getting mass manufactured or sell for large amounts of money per article. I am quite poor, and most definitely can't afford 10000$ on a single project! I have entertained the idea of finding a product with suitable electrical steel laminations and simply cannibalizing the electrical steel from there and cut them to shape to fit my purpose, but so far I have always just opted to use mild steel, which for many of the common blends have maybe about 20x worse magnetic characteristics than most blends of electrical steel... but still 50x better magnetic characteristics than just air...
The efficiency of diy motors is difficult to get very high, especially when 3d printing components out of plastic, because the tolerances simply aren't there. The air-gap between the rotors and the stator for this motor are between 1 and 2 mm... (in production motors this gap is always less than 1mm, usually on the order of 0.1 to 0.2mm). Add to that the use of non-ideal materials, inefficiencies from things like rotor inbalance and less uniform windings... I think that a diy plastic FDM 3d printed motor will not reach even 80% efficiency for the next decade.
Hall effect sensors can be used, yes... in-fact they were necessary for my next motor project which I will release probably within a month.
Once again, this is diy, made cheap... *literally* in a commie-block apartment room, I'm not sure what kind of manufacturing quality can be expected unless I order like... CNC-milled stuff, which would be too much of a monetary cost for me to take right now.
Thrust bearings should be added if the motor shaft is expected to get pushed or pulled like when a propeller is attached to it. Having said that your motor needs to be pretty darn big and powerful for this to be really necessary. Not a single drone motor (even those crazy ones that supposedly have a 2hp peak power output) I have seen, uses thrust bearings in their construction.
Of course there are formulae. I'd contest that such formulae are used in conventional ways nowadays any more though... and experimentation and optimization is the gold standard of the industry nowadays. Simply that the experimentation and optimization is done in software using finite-element-analysis models... Unfortunately, the best ones, such as EMworks, are part of larger CAD suites, which are prohibitively expensive for diy-ers to use. If you know of a good and intuitive free software for magnetic, or indeed, electric- and magnetic analysis, then do let me know! I have been looking for one on and off for some time now.
wow I love it such design and wish to see another project designing a hybrid radial and axial flux motor, RAXIAL FLUX motor.
another thing to look at is what kind of airgap you have between each rotor. The larger the airgap the less efficient it is. TESLA uses an airgap of .4mm in their latest Model S motors. (albeit different style motor), but the theory still applies to AF motors as well.
Realistically, due to there always being some unevenness in the print bed and 3d printed plastics being... well... plastics and so a little malleable, you are not really able to get an airgap smaller than about 1mm. At such scales though, the difference in efficiency is nearly negligible.
What kind of effect on efficiency would you expect the faulty coil(s) to have? I would have loved to see a replaced coil and some more testing. Nice video over all!
Good 👍
Nice, well done, but the coil issue needs to be solved
Amazing work!...........................💯💯💢💢
your motor would be able to start on it's own if you add an encoder or HALL effect sensors and operate it using Field Oriented Control algorithms, you could also try HFI
Yep, that is something I will try to look into in the future when making my next motor(s).
good Vidio ,thanks😀
Please publish your cad files so we can also play with this design?
Good effort. This motor gets hot due to eddy currents. If you don't believe it, turn it as a generator using another motor, and watch the thing get too hot to touch.
What type/arrangement of shaft are you using to make it spin from the center?
Amazing work! Could u please point to a reference for the calculations and the theory behind your design?
If you ask about something specific then I may be able to help you out. In terms of calculations made for this particular motor...? Well there were extremely few because the design was mostly dictated by the materials I had on hand. The 20x10x5mm and 20x5x5 neodymium magnets, The wire gauges I had on hand, etc... So in a lot of cases, only back-of-the-napkin precision calculations were necessary to find the best combination possible with the materials I had on hand.
@@BirdbrainEngineer okay..! Thanks
Hakko 951's are like $300 soldering irons but well worth it!
Try using plastic self lubricating bearing. Igus has some available or you can machine your own from a variety of plastics. Also from what I understand these motors get hot. And I didn't hear how much horse power this motor was rated at.
Hey, great video! Do you mind sharing where you got your magnets?
supermagnete
what about the inserts between the main (wide) magnetic poles? I guess, they are to implement the Halbach field configuration but are the narrow inserts just rotated magnets of the same size or are those just smaller pieces? Thank you for the impressive design and neat implementation.
The main magnets are 20x10x5mm, and the sideways magnets are 20x5x5mm
the further apart you have the bearings , the smoother the shaft rotates
These axial magnetic flux motors are revolutionizing EVs soon. Yasa and Magnax have an efficiency of close to 98% at a very wide rpm range which gives you about 10% extra range compared to usual radial magnetic flux motors in EVs.
Mercedes have it in their EQXX and will soon apply it in the AMG versions of their EVs.
I am not sure if production is more complicated/expensive. So far my understanding is, that these motors are cheaper because less material is needed. I also don't know how much the rare earth magnets for an 300bhp EV sized motor would cost. however, soon iron nitride magnets seem to same the day and bring the cost down
The advantage of axial flux motors as opposed to radial flux ones in EV-s is the higher power density and consequently higher power to weight ratio. This is indeed highly sought after in EV-s as it allows you to put more batteries on the vehicle, prolonging its range. Axial flux motors are much more difficult to manufacture though, as any automatic winding machines are much more complex, and simply manufacturing a good performing stator with iron cores essentially mandates the use of milling - contrast that to radial flux's need of just stacking electrical steel laminations to create the stator, it's a massive price and complexity difference.
Indeed, another problem is the need to use rare earth magnets, usually neodymium magnets, which are made from expensive, environmentally polluting and politically contentious resources.
I also looked into the iron nitride magnets you hinted at, and while its flux density of 1 to 1.5T is impressive, the coercivity is pretty low, meaning they will be quite prone to demagnetizing over time... and forget about making any Halbach array, where magnets are constantly trying to demagnetize each-other. In addition, it seems like the coercivity drops off faster with temperature than rare-earth magnets. All of which is to say, I can definitely see iron nitride replacing rare-earth in some applications, but for EV-s it would require careful cooling design considerations, which might complicate the whole vehicle design enough for manufacturers to not bother in many cases.
excelente projeto, gostei da forma como vc processou e expões seus dados. seu projeto deve ter algum erro de geometria, e por isso não iniciou direito e não obteve velocidades superiores a 3000RPM. mesmo assim manteve ótimo torque.
I think you'd need laminated iron cores between those coils if you'd want to get higher efficiency, the magnetic field on the coils is not concentrated enough. I considered using steel strapping for my own project as a go-between since it's too hard to find electrical steel, this mild steel would have more hysteresis but having any kind of iron core would likely increase the efficiency by a lot just by reducing air gap and concentrating the magnetic field.
It's just fairly difficult to fit iron cores in an axial flux motor, and indeed, it's just very difficult to source a good electrical steel material. I was thinking that maybe old transformer cores would work if cut into shape, but I am not sure about their high-frequency characteristics - maybe it changes something.
@@BirdbrainEngineer failing that you might just try protopasta's iron-filled PLA. It's definitely not as good as pure iron but it would probably be better than no core at all
@@0hypnotoad0 I believe I saw someone testing the magnetic permeability of "magnetic pla"-s and they don't have a magnetic permeability greater than 5 to 10, which is really really bad. Put ontop of that the fact that PLA melts at a low temperature, it's just not a good idea to use that in a motor one would expect to be "useful" imho. (The motor made in this video was never meant to be "useful" for anything, rather just to lean how to make one, hence the heavy use of PLA). I think in the future if I 3d print parts for a motor then they will be printed with ABS... or if it is possible with my printer, then maybe even polycarbonate.
I also built an axial flux motor. But, not only are the coils wound very differently, but I have a slotless iron core for zero cogging.
The next axial flux motor will have a more unique design for me too - this one is basic.
Slotless iron core? That sounds more like an iron backing rather than iron cores. From your channel banner it would appear that the core is essentially a donut-shaped hunk of metal? (Correct me if I am wrong) If so, then I would imagine your motor suffers from substantial eddy losses?
Your right that my axial flux motor does have an iron backing, that's what makes it slotless quite similarly to radial flux slotless. The iron provides a low reluctance path through part of the magnetic circuit.
But my motor doesn't suffer as much eddy currents as you think. The iron torus backing is made from steel strapping used to secure heavy loads to pallets. The enamel coated steel strapping is wound up in a coil where in each layer is electrically phase isolated from the others above and below so that eddy currents can not form radially, and thus significantly reduces the irons capability to form eddy currents overall. If i were using electrical grade steel with a high silicon content, the steel's higher resistance would conduct even less eddy current.
👍👍👍
with a ferrous material in between each coil and with magnetometers on the motor to measure the magnet position to optimize field position you could probably get much better efficiency.
Most freely available steel is either some low carbon steel or stainless steel... out of both categories, most blends will be suitable to act as iron cores for the electromagnets, but they are not really that great at that role. And indeed, if you are not careful, then you may actually end up losing performance due to increased eddy currents and cogging. I am working on a motor project that uses steel though, so I definitely haven't ruled out the possibility
@@BirdbrainEngineer what about silicon steel as used in transformer cores ?
@@heartobefelt Silicon steel is the most common type of steel used for electromagnet cores. Usually the exact magnetic characteristics of the electrical steel (different name for silicon steel in electric applications) are specifically manufactured to suit a task... May it be as motor electromagnet cores, transformer cores, noise filters, etc...
I have thought about using old transformer cores as electromagnet cores for a motor, but I haven't really looked much into it yet. But yes, it is on my radar as a possibility for sure.
Why do coils have a "neutral" or unconnected position, wouldn't it be better to drive the coil to the opposite polarity and push away the pole that just passed ? It would then be energized in the correct polarity to attract the next pole as well, since there are not neutral poles ?
The explanation is made with "neutral" poles in there for simplicity's sake. In reality, the ESC attempts to mimic a sine-wave pattern (which usually ends up being a trapezoidal-wave pattern) on each of the coils through pulse-width-modulation. Search "ESC waveform" on Google for images and articles on the topic.
Could you please give the dimension of magnets and coils .And also the full description of this project.
finally somebody who implements this totally logical upgrades. You have my respect, sir
Hello! Nice project! I have a question How much torque can it generate?
Do you mean static torque or dynamic torque? Static torque is very low (and I could not measure it) due to the motor being driven by a back-EMF based speed controller. Since the motor lacks hall sensors, then it can not be used with a sensored speed controller nor a field-oriented-control unit, both of which would have a dramatic effect on the static torque (especially the latter) The highest dynamic torque I recorded was 0.055N.m, however it could certainly do a lot more... it's just that my dynamometer setup broke haha... Will have to figure out a better way next time.
The iron core is probably producing more Eddie currents than helping. Thats why they are usually layered iron cores.
There are no iron cores in this motor. Only iron backplates for the rotors. There will be some eddy currents from the electromagnets but really not that much, as in the ideal case the produced electromagnet poles are moving at the same speed as the rotor. Reality is not ideal though, so yes, there will be some very small eddy currents in the iron backings but most likely not enough to actually hurt the performance.
Have you tried doing the opposite and making a generator?
I will optimize for generator operation whenever I have an actual need for it... Which is to say, *maybe* (and that's a strong maybe) in many many years' time once me and my mate might be able to afford a house...
You should write that 1.41 as 2^(1/2) because that is where it is derived from!
some of the new motors actually are called radius axial they use both both types for motor with high tourque and high rpm
And I assume higher eddy currents?
The reason the motor had trouble spinning up is because you are using a sensorless BLDC driver ( not that you could use one with sensors since your home-made motor doesnt have any ). The BLDC driver must then spin up the motor more slowly as it does not know whether or not the rotor has spun up with the induced field of teh stator or not.
Agreed, that was certainly a compounding factor. Though I think the other factors, potentially the more impactful ones were that the kV was messed up, so the ESC would have had a harder time with picking up the BEMF, and that the rotor has a lot of inertia as well as an amount of resistance, which is certainly higher than the ESC was really "designed" for.
@@BirdbrainEngineer As an improvement you could use a BLheli ESC. They are more expensive but also have better startup torque than the noname ESC that you used.
Hello
I have a goldenmotor 5kw bldc axial flux motor, I replaced the original magnets which were shaped like crescent 4cm wide and 3cm long with round shaped magnets 3.6mm diameter and 10mm thick
The motor worked well without load, but with load the torque became very low and the motor became very hot in-spite of the current was low 30 A, while hhit can withstand 130A
What do you think?
If you would have added an iron core to those windings and get them closer together + triangle Magnets the power would skyrocket
This is so cool :O Would you get more power/efficiency if the speed controller was a true sine wave controller? I don't know if I'm saying it right, but instead of stepping between the phases rapidly, the phases are controlled with an as-smooth-as-possible sine wave.
Indeed, it would be better. However, making a true sine-wave is actually not that easy to do. For example, the 3-phase induction motors that are extremely common in industry simply use 3-phase power off the grid directly. And the motor controller for a synchronous reluctance motor costs many hundreds or thousands of dollars. The cheap way to make an approximation of a sine-wave is to use transistors and switch them with pulse-width-modulation for an approximation of a certain voltage. (Usually a capacitor is also used to smooth out ripples in the "signal")
@@BirdbrainEngineer look up VESC Project, there's some vesc based escs out there that are really cheap and works with most BLDC motors
@@stealther1401 Thanks for the tip! I had planned to look into vesc based stuff once I start working on my e-bike project. FOC would be pretty nice to have.
Something is out of phase inside your motor. If you put iron inside with it you may have cause the fields to mirror each other or push out too far and this causes you magnets to be misaligned. I suggest you take the iron out and try it with just magnets and coils. Any iron should be outside of the motor's workings, like a simple backing plate.
On an axial flux motor, the only possible place to put an iron backing is on the rotor(s). This is a very common thing to do on axial flux motors. The iron backing only acts as a low-reluctance path for the magnets to couple to each-other and ever-so-slightly increase the magnetic flux density in the airgap of the motor, as well as minimize the magnetic field outside the useful working area of the motor. I am fairly certain the problem is in one of the coils (maybe i ended up winding one coil the wrong way... though i did quickly check for that and at first glance it didn't seem like anything was wrong). For the next axial flux motor I will take more care to triple-check every assembly move I do.
Would it be possible to make this as a hub motor instead of a shaft motor? Like the electric motorcycle style, like the BLDC
QS hub motors found on alibaba
Probably. Would need a redesign of the chassis though. Also would need to be designed for a lot higher power draw, since a 35W motor would have a hard time getting an e-bike going even with a large gear reduction. In the future I will probably attempt to make a diy electric motor for an e-bike conversion, because it feels like it would be a pretty fun larger project to undertake. I'd aim for around 250-500W motor then though.
Yo, I'm trying to do something similar as a project, where did you buy your winding wire?
A hobby electronics store. It could be under different names: winding wire, enameled wire, magnet wire, transformer wire...