A "multi stranded wire" vs "a single strand" as you put it... Bob it all comes down to circular mils. A circular mil is a term used for the wire used in electrical wiring to measure the cross section of the wire. We use circular mils in measuring the coils used in electric motors by adding up half of the coil group. Example, if you have 10 turns that make up a coil (half goes on one side of the slot and half on the other) then we could add up the 10 wires used in a slot. If let's say.. because we are in Merica... the motor used one 25awg wire then the circular mil of that wire is 320 so the coil would be 10x320 or 3200 circular mils. If each coil group uses more than one wire then you would add up the three wires like above to get the circular mils. The benefit of using more than one wire is you can pack more circular mils into a slot however by using more than one wire you also have the problem of the coil not being as robust and shorting out one wire within the group like you mentioned but it also could overload the ESC connected to that motor as well for the motor would be out of phase since it is wye connected. Another issue with using more than one wire is higher frequencies create what is known as the skinning effect. The skinning effect is when the electrons move around the outside of a wire. This skinning effect can cause electrons to jump across the wires within each coil group effectively shorting them to one another. This effect usually happens when the motor is wet or is using high frequencies of more than 60Hz (BTW this is why 50Hz is so much better). The skinning effect can cause eddy currents that in turn creates hot spots within the winding. This is why using using smaller wire is NOT ideal. I also noticed that the motor you shown with the multiple wires is a mess and has a lot of crossing of wires. This is not electrically efficient because now the wires are not even across the stator and the skinning effect could be worse. We call that kind of wire in the industry a mud winding and is the most inefficient winding that can be done. A single wire benefits from not only being more robust but also limits the amount of skinning. It's more electrically efficient and produces less of a chance of skinning. The problem as you pointed out is that you can't pack as many circular mils per slot because of the air gap between wires. You mentioned a phase change if you braid your lead wires... this is the effect of skinning BTW.. same goes for crossing electrical wires or Ethernet wires and also why cutting the motor lead wires uneven to hook up to a 4in1 for a cleaner build is not good practice. The best winding for these motors would be to use flat wire. With the use of flat wire they could pack more circular mils in each slot and still use just one wire. This would be harder to do (sort of) but overall it would be the best. I would also be interested how they deal with slippage when using these different magnets. The best bearings to use would be ceramic balls with stainless steal races and no grease.
Thanks brother, The one thing is the equation is also price. If they used ceramic bearings, flat coil wire, titanium shafts and so on then the price point may be so high that the consumer may pass :( anyway love the work you put into your videos and you are a true asset to the hobby.
Definitely no problem to build custom made motors with flat wires, ceramic ball bearings, selected mark aluminium, titan shafts etc. etc. However such motors would get in same category as devices made for James Bond and will cost so much that regular folks wouldn't afford them. Although I wouldn't be surprised if someday such kind of motors will came out in custom made quads created as gifts to the sons of the Arab sheikhs. Or some other kind of hobbyists with very deep pockets would create them for themselves. Of course such kind of quads can't participate in common races because it will be equal to use of steroids in Olympic Games.
Ok.. a few things... Aluminum doesn't "rust". It does oxidize nicely, forming a layer of aluminum oxide over the surface of the aluminum giving it the grey haze. When iron rusts, the material expands exposing more iron to the elements. That "aluminum" you spoke of is something else. One cannot add an additional stater to an ESC controlled motor and expect it to work. The 3 wires into the motor force the configuration to be a multiple of 3: 9, 12, 15 ect. A tube is not stronger than a rod of a given material of the same diameter; removing 1" of material from the center of a 2" diameter cylinder does not magically make the cylinder stronger. A tube is stronger than a rod given the same amount of material.
removing the center material does eliminate a shear point for rotational torque force. done on high hp race cars. not all deformation is elongational. ie prop stops from hard crashes on high throttle.
UNREAL!! Is the word of the day. This was one of the most informative videos on the industry I've seen yet. I have such a better understanding for this section of the electronics market. The construction technique is varied and now I know what to look for. Thanx again mate!! :-) :-) :-)
Interesting video, thanks. I burnt out an X5 bldc motor a couple of years ago by trying to use it to propel a bike. So, instead of buying another, I took it apart, noted the winding layout - 4 stranded 15 turns and rewound with similar magnet wire. Really proud to say that it worked as good as new! So rewinding a burnt out motor is possible, but as it takes a load of research, patience and a couple of hours I think most people would just buy another!
.1mm laminations is the thickness of the individual sheets of metal stacked up to make the stator, NOT the glue between the sheets. Glue thickness is insignificant... Tell those motor manufacturers to use SQUARE wire. That would make the ultimate motor... Awesome presentation.
Holy shit. The lamination makes total sense. As an a audio specialist I know how lamination of a strand of wire effects the sound, the material of lamination does too. It's all about the inductance control. Yes in an audio system you can hear it. I can see how it effects the performance of the motor. Wow!
The "hollow shafts are stiffer than solid ones" is totally incorrect. The misconception seems to stem from the fact that a hollow shaft is stiffer than a solid one of the same weight. A solid shaft of the same diameter will always be stiffer than a hollow one. Also, the race to make smaller diameter bearings is terrible for durability. Moving from 4x9x4 in the BH R4 down to a smaller 3x8x4 bearing in the new R5 has in my (and many others) experience made the bearings much less durable. Like, a few weeks and the damn things are sounding gravelly. The race to increase power, size, while keeping weight the same has had some rather crappy tradeoffs in motor design IMO. I would gladly give up a little power or increase the weight a little to get a motor that doesn't go bad after only a few weeks of use
Oh yeah, the other thing, when you put a steel core into an alloy hollow shaft, you're basically getting the worst of both worlds. The steel isn't in the position where it could add the greatest stiffness, and the alloy is now being used for threads, where it can more easily get stripped/damaged. I would love to see more motors with steel/Ti shafts, necked down to 3mm internal. The added space could be used to have a bigger BB in the bearings, and offset some of the durability loss we've seen with these super small bearings.
Yeah I totally agree, I think in a generation or 2 of motors, we'll see the retaining screw trend die out. Between the difficulty in removing them, and the need to compromise the shaft itself, plus the extra expense of machining the threads, they're just not great. It's funny to hear about the cheap thread locker being such an issue in china, I've had nothing but bad experiences with cheap Chinese stuff, in the end, I just paid the exorbitant price for a bottle of the real deal here in NZ, and never looked back
DossKat R5 is not 3x8x4, it is 4x8x3. Smaller balls are absolute crap, never ever use them, like ever! 3x8x4 are the same ball size as 4x9x4, just as durable.
Or solid titanium shafts with a bottom screw. Nothing says the shaft has to be hollow all the way through to have some threads just at the bottom. Just drill 5 mm in to the shaft and tap.
Looks good man! Watching now. I rewind motors as a side hobby in order to improve their efficiency, power output and alter their kv if needed. Lots of good info you posted. I should show you large spreadsheets of data and algorithms I use in order to derive my info before a rewind. Thanks for posting this video! Lots of good info and similar to a video I keep meaning to make/post. Appreciate all your good work in the hobby!
Enjoying your videos, and I have a quick question. and you seem to be the person to ask. Or if anyone can chime in here? It's about the wiring type and size between the battery and ESC. It's DC but there is some ripple current flowing, as the pulsing from the ESC loading and unloading causes some voltage fluctuations. Understand that part... Question is: What type of wire is truly best of this application? where do the electrons flow? on the surface? or is it all about the cross sectional diameter of the wire? Is the silicone "Cat Hair" wire with many strands better for this application, or are fewer strands better? Why the difference between the silicone insulation as opposed to the normal rubber insulator on automotive wire, or marine wire? Is it about the heat? of course the silicone wire can take more heat, but being a better thermal insulator, it will trap the heat in the wire as well.. I have a friend who is a rocket engineer who seems to think that the hobby industry has got it all wrong, and that solid wire would be best to go between the battery and ESC. Just trying to find out the fundamental truth, and very ha
So are mult strand stators more efficient or single strand? If the single strand can handle heat better wouldn’t that be more efficient? Looking for longer run time?
The quick of it is a China company will release a great product for cheaper than they can make it and take a loss on the first few batches. Once it is "hyped" as being an awesome product for the $$$ and the market gets saturated they will degrade the product to cheap crap and double their money back. By the time everyone figures it out it is to late , but once the word gets out it is shit they will stop the cheap crap and re release the good one under another name and do it all over again.
That's what landed me in China in the first place. We got several 100 great products and the next thing we new our stuff started failing all over America nearly ruining our reputation and biz. They have no scruples..NONE..I am constantly on the go traveling all over China to my suppliers pulling unannounced surprise visits.
Kabab FPV at its best right here! Living in south est asia, i know perfectly this run for fake and copied products! It's really something and some shops don't actually hide that the products they have are fake! It's really a big cultural business here! Have a great week and may the floss be forever with you :)
If i did understand, in the future we may get only one ring magnet in the bell when the manufacturers will be able to make it ? Another question, why not full iron in the rotor instead of thinner and thinner laminations, cost, durability ? Ps: the effect your were looking for with thick wires is the skin effect (translated from french, may be called otherwise in english) I love your videos and this one in particular, very informative and moreover comprehensive, don't forget to...floss !
One big solid stator would work except that when you flip off the magnetic field of the poll, you're gonna get a bunch of residual magnetic field which will suck the strength out of the neighboring polls and also cause more resistance the next time that poll will need to reverse magnetize. It will heat up very quickly and generate less power.
the variation of the magnetic field induces currents inside the iron stator. these currents produce power losses. the stator is laminated to increase electrical resistance while keeping magnetic permeability. if you want I explain it here czcams.com/video/hW1ew73Dnoo/video.html
Hmm ok i understand then better the constaints involved in between having still more layers for less Eddy currents and the need of insulation. Nice video by the way
Many years ago I took apart a motor that was a direct drive capstan for a very expensive tape deck. It was being replaced because it's hours of use was near the specified limit. It still worked perfectly. One thing that really struck me about this motor was that it had no detectable cogging, whether it was powered or not. When I got it open, I found that the stators were slightly helical. By putting a piece of dowel rod and a ball bearing inside the sleeve bearing, I could get the motor half assembled. When half assembled it had noticable cogging. I wonder if helical stators would help reduce the vibrations in drones? Maybe your engineer friends might know more about this...
What you may have been looking at is a brushless induction motor which are actually more common than the permanent magnet motors we use. Induction motors typically have that twisted design. It probably wasn't a stator you were looking at either. From my understanding they're more expensive to manufacture and higher end. Or maybe it was and I've over extrapolated
@@Kabab the motor was an outrunner motor with the drive electronics attached to the back plate. I believe it had servo feedback. It could run at variable (but very low) speeds in either direction, and it did not seem to change speed with load. It maxed out at about 30 inches per second. I think the tape machine was used for scientific or forensic use. It had no record capability at all and it could handle everything from disassembled microcassettes to 1/2 mono reel to reel. It had a turret with about 8 different play heads to handle different widths and track counts. The playback electronics were external, you had to run BNC cables from the turret. There were different attachments to hold different kinds of tape reels too. The motor had ferrite magnets in the rotor in what I now believe was a halbek array (I did not know what that was back then). It weighed about 10 lbs and the tip of the rotor was the capstan. I do not know if that is consistent with a brushless induction motor or not. At 10 lbs it would make a really poor drone motor, but even with a stethoscope you could not hear whether the motor was powered or freewheeling. It has always amazed me that it was even possible to make a motor that smooth. The direct drive motor in my then-new Dual turntable sounded like a chainsaw by comparison.
@@jdrissel very interesting. There is VERY little in this department that's original. Nikola Tesla invented probably more than half of the basic tech that has made our modern world possible. Manufacturing has just gotten to the point where where we can produce half assed parts rather cheaply but the high quality stuff is still amazing and expensive to produce as it always was for hundreds of years. I'm sure you can figure out what exactly what motor is. If it's a true halbach array it's a pretty highly engineered motor.
Hey what if keep two 2306 motors side by side and switch the bells For example 2 motors are named 1 and 2 are of same dimensions same kv or different kv I take the bell of motor 1 and put it on the stator of motor 2 and the bell of motor 2 on the stator of motor 1 could u please answer this question
Is there any sense going for Emax RS2205 2600kv at this point of tech development considering they are only $9.99? All other "better quality" motors costs mostly double. Or are those newer tech motors so much better? Motors are meant mainly for freestyle with quite a heavy 5inch quad. Appreciate your opinion.
Hey have you had a look at the efaw? Line? Particularly the 2407 stator size. What do you think about this motor on a floss 2 frame. No go pro and used as a daily flying acro? I know you're busy, your thoughts on rather I should go with the hyperlite 2207 or try this new 2407 draw, would meen a lot to me, I know you know your stuff.
Are you sure that thicker wire coating doesn't *help* with eddy currents? I spoke with an engineering professor that suggested better care be taken to keep dust from getting inside the bearing. As the balls roll around, the dust is crushed and refined until it becomes very abrasive and the pitting of the ball bearings snowballs. With regards to the aluminum shafts, a friend of mine found that after flying a sessions' worth of packs without changing props, the threads on the shaft were completely ruined. They had essentially disintegrated. 21:35 fillet to reduce stress concentrations 23:18 incorrect, unless you're referring to stiffness/weight If your bearings are rusted on the outside, they're likely rusted on the inside too
This is a very old video by now. Very very old. Much is incorrect as I've learned. Also, keeping your bearings dust free is merely an academic task. In reality, it's impossible as you're crashing in sand and dirt. Eddy currents are reduced with thinner laminations.....they are literally 'thinner' for lack of an easier explanation. There are no aluminum shafts. Those would be awful. Only solid steel, hollow steel and both in hardened or regular. Also most recent motor bearings are 9mm OD now so the bearing issue is moot......goes on and on. Much has changed.
@@Kabab My T-motor F40 Pro IIs vibrate quite a bit, I assumed it was bad bearings. I'm not sure how to get you a picture of these wrecked motor shafts, YT doesn't allow links in comments.
@@dominiclallande it's unlikely to be as a result of the bearings as even crunchy bearings aren't that out of balance. It's more likely to be as a result of scrapes and dings in the motor bell or prop shaft. Oh yeah, that's what you meant by aluminum prop shafts. Yeah those are trash.
I suppose it would be better to wind with copper tape instead of just one thread or multi thread, the same as that used in the toroidal transformer but in copper.
+David Mendoza Vargas seems logical but the electronics actually bunch up on the surface so they aggregate on the corners of a rectangle ribbon. At least this is what I'm told. Round wire is better.
Great info, podcast fore sure. Not sure about the BG product issue though. Obviously this is possible with an unknown brand but if your sticking to well known manufacturers like Emax, fatshark/immersionrc and the like then I doubt there is any risk. I bought the aokfly motors from the first batch and broke a motor every crash. Mainly bent shafts and base plates/mounts. They were smooth and powerful but no durability. The same punishment has never destroyed an Emax rs2205s. With over 200 orders from BG they have always replaced an item at no cost or thrown money at me. They've yet to cause me concern.
Just saying, I don't think you measured the length of the stator arms the same way for the 2406 motor at 12:10. You measured from the green bit to the tip while for the other motors you measure from the start of the windings to the tip.
Thank you for taking us on your knowledge journey lately. Also, kudos to people who comment on these types of videos too. Sometimes I learn just as much from the comments as I do in the videos.
My understanding was that the stamped steel stator sheets stacked together are in itself a laminate and the sheet thickness not the adhesive that binds them is what they are referring to when they speak of .0xxx laminate stator. So, i was supersized to learn it was actually the enamel adhesive they were referring to. I gues it makes sense either way. Thanks for the great vids P.S i need to brush and floss come to think of it !!
I thought the same and I kinda think we're both correct too. Something may have gotten lost in translation but I asked that question over and over and got the same answer so I'm assuming that's what it is...?
make the podcast dude, im super interested. its a bitch to do your own research, and with the fact that you know people on the "inside" it makes it that much better. please do it!
I've been waiting for a technical podcast, one where you can listen to educated people have interesting discussions, giving insight for all the components that we use. I just happen to have a particular appreciation for all the details we often ignore in the way our quad's components are made :)
The single best video i have watched in years! Respect! Alot of info... but most importantly.. alot of reference points for me to go and research and learn even more! basicly all you want to learn about motors lecture!
NIce job. Interesting insights into the Chinese culture. I suspect change is coming on that front. Too bad about Bangood, they used to be pretty reliable, but it's been a while since I ordered anything from them. Lately I hear a lot of people bashing them, Now I know why, from what you say, things have changed, and NOT for the good. Too bad. The upside is that recently there's a lot more places in the US to get your Quad parts, and the prices are on par with Bangood. I've not received any fake goods from any of the US sources, and prefer to keep by business here whenever I can. That makes the loss of Bangood as a supplier no big deal. Thanks for the heads up, and again, great job in 1 take. Tech comment: As an engineer I would like to warn folks that aluminum threads and aluminum nut are a formula for disaster, they GALL, which is a technical name name for cold welding, and it's about as bad as it gets. Once galled, something is going to break. You can't tighten OR loosen the galled nut. It just stops. Bang, right there. (It also happens with stainless steel on stainless steel usually if assembled dry (no oil or grease), and it's not from overtightening, it happens with finger tight fasteners, but overtigntening can break thru the lubrication film and bring it on. It happens because of the way the metal molecules interact, and that's a physics lesson, and over my head. I've seen it happen too many times to count, it's the bane of auto racers using aluminum hose fittings. ( I used to drag race in another life) On the 3B (BBB 2207) Motors (or any aluminum thread motor), just use steel nyloc nuts, a touch of oil (or even better anti-seize Vaseline works in a pinch) and be careful not to overtighten them and they should be fine. The upside is the steel nuts are MUCH cheaper and don't weigh enough more to notice. The Underground site says aluminum, but also says the shafts are titanium, I'd imagine (hope) the motors are supplied with steel nuts, if not, then save the alum ones for your other motors and get some steel ones to use with the BBBs. Steel shafts use Alum nuts (Steel OK) but on Aluminum shafts use steel nuts (never Aluminum). Titanium is OK for either if you don't mind 7 bucks for a nut that saves you .2 grams Thanks for the sale heads up and link to Underground, I may order a set of 3Bs when they are back in stock
I'm giddy about the BBB motors too... Also slightly concerned about what grade of titanium can actually bring that cost down to a $3 delta per shaft (though to be fair, all my CNC mill/lathe experience with titanium is for satellites), to the point where I keep coming back to the old RS2205 EMax motors as being actually not garbage - big air gaps, N50 rectangular magnets, but they take a beating, spin smoothly, and handle 5S like champions.
The T-Motor Air40 motors have an aluminium shaft and were supplied with aluminium nuts. I found this out after twisting the tops of three of the shafts off trying to remove the nuts on brand new motors. Luckily there was still just enough shaft to tighten down a prop with a steel nut. I am definitely not a fan of the aluminium shaft.
May be a stupid question , Is there a reason why they couldn't use a magnetic ring instead of individual magnets? What sort of issues would it cause if any? Or using large arc magnets that would only require 2 or 4 magnets to cover the I.D. Of the bell?
Dixie9mm not stupid. It's because they can't create a strong enough magnet in the ring. And the whole ring can't be one magnet because there need to be alternating polls to push and pull against.
So a larger gap between magnets could make more power? I'm sure there is a point diminishing return in there somewhere. But a tight gap between magnets means smoother motors but could lose power? And they make up for it with stronger magnets? Among other variables, tighter laminations etc....?
What do you prefer for freestyle flight 2307 or the 2405. I'm interested in a build using one of these motors. I built a floss with 2306 emax motors which I love i get a lot of electric noise manifested in my video feed. Do u think installing a cap on power leads would help this problem?
For the "bending the shaft" part: when you look at a punctual bending you are not facing momentum but shear force. Thus a full shaft is much more resistant than a hollow one (since shear force resistance is proportional to the section's area of the shaft)
Yes this makes sense except that you can bend a solid shaft easier than a hollow one on these motors. A hardened solid shaft is strong enough not to bend however.
@@Kabab ok that is strange. Maybe they whent for a too much thin wall for the shaft. Still, if the bending happens in that particoular point (con ection to the bell) is definetly shear force doing it. If instead the bending happens in other spots I really can give you no explenation other than the one above.
Kabab FPV Must be top secret lol. I just picked up the 2405 2722 for a floss 2 and I'm extremely impressed! I've tried the 5046 cyclones and the 5050c cyclone bi prop so far and the 5050c feels and sounds amazing! I honestly can't believe I can get about 4 min on a 1300. Weight is 290g dry.
I really like my 2400kv T-motors. But trying the hypetrain 2450kv to see how those are. T-motor being the OEM is a nice touch also. What do you think of the hypetrain motors and T-motor pro 2 2400kv motors. I have a feeling the kv isn't high enough for you? Thanks so much for all the info. I think some of it sunk in
The kv is fine, I just don't think they're anything special at all. Not even a little bit. It's just another motor with a top shelf price tag and some marketing. They're fine motors, just not all that different than comparable motors.
now im not so sure about getting new motors from banngood.... i thought of getting those bbb motors but their kv and amp draw is kinda scary, how much flight time did you get with the 2207 bbb motors?
By my pocket calculation, should be pretty decent, unless you're spending all day at WOT. 5x4x3 class draw, even on 550g quads and junk batteries will keep you in the air for 7m if you're being a patient llama.
hey sorry, irrelevant question but im currently in the process of assembling a quad (i.imgur.com/sGTwUzV.jpg pic related) together and had some wraith 32 50A ESCs laying around, i know they are overkill with me only running 5 inch hypetrains but is there any benefit to running these over the 25A variant?
The latest motor stuff I'm going to be announcing in a couple months will be very interesting...this video is very old by now and some of it is not quite accurate. A lot has been developed since then...
but does 3wires not meant 3 times more enamel, because the thinckness is equal an thinner wires have a higher surface per crossection than thick wires? Probably there is an optimum between surface effect and less copper per available space, but if multistrand is clearly better?
I think the advantage of the multi-strand, is that it will pack better around the stator, meaning that you can get more copper on the stator. The total power of the motor is proportional to the volume of copper on the stator. That's not to say I'm personally favouring multi-strand though. These quad motors are operating in a very harsh environment; imagine the stress they suffer when you suddenly freeze a motor during a crash, with full current applied by the ESC. I think the added cooling benefit of single-strand is preferable - definitely IMO.
12:40 - Multi-strand vs larger single strand winds.. all other things being equal or identical; motor mechanicals, wire/copper quality, plating type/quality, enamel, and equal wire volume (pi*r^2 x3 or pi*r^2 x1)... the single strand wins every time and here's why.. A multi-strand motor on A/C does indeed have an advantage due to the increased surface surface area, but that advantage doesn't last long. Many of those strands are packed densely into a unsightly wad and are unable to dissipate heat as efficiently. The inner strands have no exposure to passing airflow and radiate their heat outward into other wires, as heat builds resistance increases causing higher amp draw, even more heat, less power production per amp and less efficiency overall. Also, all of that stator heat-soaking can/will compromise the cheap home-brew sleeve adhesive used to glue the stator to the base. I've had several stators on multi-strand motors (one specific brand is a repeat offender) rotate on the base, loose timing, get real hot, and fail. I've never had a single strand stator rotate on its base. Solid strand wires in quad motors have direct access to airflow resulting in less heat build up, better sustained efficiency, higher amp capabilities, faster recovery from high amp draw moments (punch outs, etc), doesn't heat-soak the stator, adhesive, and magnets as badly... and all of that trends across multiple packs run back-to-back. As a bonus, solid strand is more durable and looks better. Look, these things are expensive and we beat on them, the lightest weight best performing is rarely the best for freestyle use... buy motors with single-strand, thin stator laminations, good bearings, thick(er) titanium shafts with C-clips (if you can find them), thick(er) bells, meaty bell hubs, curved N52's with a airgap that'll tolerate some grit/dirt/debris and impact flexing without binding up or knocking magnets loose.. from someone who also sells replacement bells.. When you find that motor, buy enough for several quads, buy spares, and don't chase the latest-n-greatest with someone's name on it.. fwiw.. the above info comes from my own hand-winding of many MicroDan 2505 and 2510 motors with all sorts of wire, turn counts, both termination types, all tested for amp draw and thrust using a regulated power supply. See gobrushless.com if you want sore finger tips and a headache.
I prefer single strand just because it's more durable. The debate goes both ways forever however. At the end of the day the difference isn't detectable to me at least.
Bob thanks for the Banggood heads up. While I very very rarely order anything from them anymore and when I do its misc crap that has no brand name attached to it . That info will really help steer people's decisions.A clone is one thing a true replica is where I personally draw the line. Anyway great video and bring on the podcast :)
While you're not a professional expert, you have put in the time and effort to learn this stuff, which has made you a layman's expert and stating anything other than that does you a disservice.
'I don't really know what I'm talking about'... Uses technical terms and reasoning like a boss. Lol. BTW, Loctite was purchased by Henkel corporation in the 90s. Was it ever owned by 3M?
When using multiple wires it reduces losses. You can use litz wire to do the same. The iron around the outside helps guide the magnetic field. The field travels more through iron than air and iron works kind of like a wire for the magnetic field increasing the strength.
Interesting and informative. Good Job Bob! I'll throw this in: No manufacturers and very few motor winding hobbyists use a winding technique known as Zig-Zag DLRK. I exclusively use Zig-Zag DLRK when I rewind my own motors, with either delta or wye termination. I think it is easier and neater than standard DLRK once you learn it and do one. It may also be more efficient based on what I've experienced. Shall we bring this into the conversation? I've got winding diagrams, tests and pics of motors I've done (years ago at this point). You know where to reach me. Later! :)
Can you do a comparison of the Finx23 and 30 by ZMX? Also the pros and cons of Taller vs Wider stator motors? Also, your videos are very nice!!! Cheers from the Philippines 🇵🇭
The two ones, more iron allows more magnétic flux (1), the copper plays in two ways, more copper (surface) results in less electric resistence (2), and more windings let you do the same job with less current(3). 1 - en.wikipedia.org/wiki/Magnetic_reluctance 2 - en.wikipedia.org/wiki/Electrical_resistance_and_conductance ( resistivity and conductivity) 3 - en.wikipedia.org/wiki/Magnetic_circuit (MMF) Note - one winding with 3 wire conected in parallel, doesn't count as 3 widing.
So much wrong with the magnet parts dude. Magnetic fields are only reflected back under super-conduction (meisner effect), the closest in normal everyday situations would be diamagnetism, which is too weak for all intents and purposes. Thinner stator laminations are useful in that they reduce the eddy current losses, but only if the thickness is is larger than the magnetic penetration depth. ANy thinner and you will cook the laminations (also you don't pack more iron in the smaller the laminations, quite the opposite actually since you will have that thin gap in between the plates which reduce the total volume. But the silicon-steel laminations also has a much lower hysteresis energy. The only reason for thicker wire is actually the lower resistance, but you have less windings then. Also you have more eddy losses in thicker wires. On thinner wires you also have a less efficient coil since the individual windings are further from the ferromagnetic core which will reduce the "captured" flux. Also the thinner wires will increase the inductance (if there are more windings) which will influence the choice of the signal generator you are using. So all in all its a continuous game of trading trade-offs (lol) to try and get the best performance and efficiency (not necessarily the same but frequently overlaps to a large extent).
I see that this video is 6yrs old... I'm doing a build and this video came on in the background and man this must of been your tweaking days. sounds like your all hyped up on something... it was just funny how fast your talking in this vid..... Thanks,
Which motor do you recommend to replace from eachine 2206 Wizzard X220S? BBB 2207 or AOKFLY 2306? Both are under 15$ and that is the requirement. 4in1 30A ESC is enough for BBB 2207 or AOKFLY 2306?
HYEonDEATHROW depends how and what you're using it for. I personally prefer the 2207 for all things 5" and 4S. The 2307 is an incredible 6" star. The 2405 did not perform well for me at all but people are liking it a lot some how. We're making some size variants for direct comparison testing.
less winding means higher kv and more heat generation from increased power draw. No matter what, a tighter air gap is always better. Better for all aspects of the motor function.
DId you test Egodrift Motors? They are supposedly one of the few motor producers (aside from BH and Sunnysky, ha i've even got some 2212 from them for my Discovery) They are like 5 Minutes down the road from our newest spot. I meant single strand by lesser windings, so more cooling area and no block of tangled 3-strands
multiple strands are supposed to have the same overall cross sectional area but more surface area. Apparently the electrons travel along the surface area and so having more us supposed to mean lower resistance. At least this is what the general theory is.
Yes actually I was wrong, but the overall weight of the solid wires would be drastically lower. Almost equaling 0.453 grams/feet. On another note, I recently purchased the Hyper lite 2405-1922kv motors. What do you think about that? Do they stand good chance for longrange/semi freestyle?
+James Grow well I've never heard or seen any issues work braided wires but it does make sense. I wouldn't expect just one crossover to matter. I always use blheli anyways because I don't like messy wires.
Do you know if the optimal magnet thickness is proportional to the length of the stator arms? Another thing I'd like to know is why all motors are designed to have such high peak torque compared to what they can handle continuously without overheating. Logically that means the iron is nowhere near saturating when the coils are running at their continuous current rating. Continuous torque to weight ratio is what I'm most interested in for robotics, so I'd rather trade some iron for more copper.
Right. The answer to your observation is a skewed stator which will reduce peak output but increase average torque and power. Coincidentally, fettec has just made a sine ESC that matches the more natural response of the motor to inputs which would be a perfect match for a skewed stator for an overall 'smoother' running craft with more average range performance. This would be a very minor improvement on what we've already got however
Awesome knowledge bomb. I learned first-hand about unscrupulous Chinese manufacturing with my first and last crowdfunding investment, the Kreyos smart watch.
+KANGI I've discussed this a lot in more recent videos. I think the one from last weekend. The one with the 'table of contents' in the title image. It has to do with handeling and the specific props that I prefer.
A "multi stranded wire" vs "a single strand" as you put it... Bob it all comes down to circular mils. A circular mil is a term used for the wire used in electrical wiring to measure the cross section of the wire. We use circular mils in measuring the coils used in electric motors by adding up half of the coil group.
Example, if you have 10 turns that make up a coil (half goes on one side of the slot and half on the other) then we could add up the 10 wires used in a slot. If let's say.. because we are in Merica... the motor used one 25awg wire then the circular mil of that wire is 320 so the coil would be 10x320 or 3200 circular mils. If each coil group uses more than one wire then you would add up the three wires like above to get the circular mils.
The benefit of using more than one wire is you can pack more circular mils into a slot however by using more than one wire you also have the problem of the coil not being as robust and shorting out one wire within the group like you mentioned but it also could overload the ESC connected to that motor as well for the motor would be out of phase since it is wye connected. Another issue with using more than one wire is higher frequencies create what is known as the skinning effect. The skinning effect is when the electrons move around the outside of a wire. This skinning effect can cause electrons to jump across the wires within each coil group effectively shorting them to one another. This effect usually happens when the motor is wet or is using high frequencies of more than 60Hz (BTW this is why 50Hz is so much better). The skinning effect can cause eddy currents that in turn creates hot spots within the winding. This is why using using smaller wire is NOT ideal. I also noticed that the motor you shown with the multiple wires is a mess and has a lot of crossing of wires. This is not electrically efficient because now the wires are not even across the stator and the skinning effect could be worse. We call that kind of wire in the industry a mud winding and is the most inefficient winding that can be done.
A single wire benefits from not only being more robust but also limits the amount of skinning. It's more electrically efficient and produces less of a chance of skinning. The problem as you pointed out is that you can't pack as many circular mils per slot because of the air gap between wires. You mentioned a phase change if you braid your lead wires... this is the effect of skinning BTW.. same goes for crossing electrical wires or Ethernet wires and also why cutting the motor lead wires uneven to hook up to a 4in1 for a cleaner build is not good practice.
The best winding for these motors would be to use flat wire. With the use of flat wire they could pack more circular mils in each slot and still use just one wire. This would be harder to do (sort of) but overall it would be the best. I would also be interested how they deal with slippage when using these different magnets. The best bearings to use would be ceramic balls with stainless steal races and no grease.
I wish I could pin multiple comments. I'm gonna pin this one for now. It's good info and an excellent example of of the ongoing debate.
Thanks brother, The one thing is the equation is also price. If they used ceramic bearings, flat coil wire, titanium shafts and so on then the price point may be so high that the consumer may pass :( anyway love the work you put into your videos and you are a true asset to the hobby.
Preach brother. This reminds me of some of the design problems engineers had with DC brushed motors for RC and the full scale.
Remember they use to sell hand wound motors...was like 60-70 bucks in the early 90s.
Definitely no problem to build custom made motors with flat wires, ceramic ball bearings, selected mark aluminium, titan shafts etc. etc. However such motors would get in same category as devices made for James Bond and will cost so much that regular folks wouldn't afford them. Although I wouldn't be surprised if someday such kind of motors will came out in custom made quads created as gifts to the sons of the Arab sheikhs. Or some other kind of hobbyists with very deep pockets would create them for themselves. Of course such kind of quads can't participate in common races because it will be equal to use of steroids in Olympic Games.
Great you are chatting with these motor manufacturers directly, top work and a really interesting watch! Cheers.
Ok.. a few things...
Aluminum doesn't "rust". It does oxidize nicely, forming a layer of aluminum oxide over the surface of the aluminum giving it the grey haze. When iron rusts, the material expands exposing more iron to the elements. That "aluminum" you spoke of is something else.
One cannot add an additional stater to an ESC controlled motor and expect it to work. The 3 wires into the motor force the configuration to be a multiple of 3: 9, 12, 15 ect.
A tube is not stronger than a rod of a given material of the same diameter; removing 1" of material from the center of a 2" diameter cylinder does not magically make the cylinder stronger. A tube is stronger than a rod given the same amount of material.
All makes sense. Pinned. Thanks.
removing the center material does eliminate a shear point for rotational torque force. done on high hp race cars.
not all deformation is elongational. ie prop stops from hard crashes on high throttle.
Isn't the flux ring ferrous, and wouldn't that mean it's iron-based and could rust?
Marc Wasserman the flux ring is painted steel. But he pointed out the aluminium portion of the bell...
KillaG FPV 👍
UNREAL!! Is the word of the day. This was one of the most informative videos on the industry I've seen yet. I have such a better understanding for this section of the electronics market. The construction technique is varied and now I know what to look for. Thanx again mate!! :-) :-) :-)
Thank you for clarifying my long time suspicions
Please make more videos like this!! Love the knowledge bombs you drop
Great content Joshua Kababwell!
lol
I WENT BY THIS VIDEO AT LEAST THREE TIMES BEFORE I WATCHED IT BUT I WAS RIVETED TO IT FOR THE WHOLE 34 MINUTES . LOVED IT . THANKS
Interesting thoughts on Banggood, I don't think anyone has explained it that way, but makes sense
Interesting video, thanks.
I burnt out an X5 bldc motor a couple of years ago by trying to use it to propel a bike.
So, instead of buying another, I took it apart, noted the winding layout - 4 stranded 15 turns and rewound with similar magnet wire.
Really proud to say that it worked as good as new!
So rewinding a burnt out motor is possible, but as it takes a load of research, patience and a couple of hours I think most people would just buy another!
Would really like to hear that podcast
D Rock 75 yep this definitely needs to be a podcast
Yes!!!!! This sort of podcast would be AWESOME!!!!!
This is gold. Thanks for doing all the research and sharing.
Wow.. Bob you are real.. at the end of the video... Damm.. thanks for talking real!! Follow you all the way!!
.1mm laminations is the thickness of the individual sheets of metal stacked up to make the stator, NOT the glue between the sheets. Glue thickness is insignificant... Tell those motor manufacturers to use SQUARE wire. That would make the ultimate motor... Awesome presentation.
Charlie Olson that's what I always thought too. I asked them this question multiple times and got the same answer. So I figured I was just wrong.
Informative. Bring the podcast!
Holy shit. The lamination makes total sense. As an a audio specialist I know how lamination of a strand of wire effects the sound, the material of lamination does too. It's all about the inductance control. Yes in an audio system you can hear it. I can see how it effects the performance of the motor. Wow!
Will u also recommend to floss in between-magnets later when they will get very tight? :D
comment or cancel... hmm...
34 mins plus in one take = priceless. good info man.
the number after N is not a random number is just the magnetic force per volume of a given magnet
The "hollow shafts are stiffer than solid ones" is totally incorrect. The misconception seems to stem from the fact that a hollow shaft is stiffer than a solid one of the same weight. A solid shaft of the same diameter will always be stiffer than a hollow one. Also, the race to make smaller diameter bearings is terrible for durability. Moving from 4x9x4 in the BH R4 down to a smaller 3x8x4 bearing in the new R5 has in my (and many others) experience made the bearings much less durable. Like, a few weeks and the damn things are sounding gravelly. The race to increase power, size, while keeping weight the same has had some rather crappy tradeoffs in motor design IMO. I would gladly give up a little power or increase the weight a little to get a motor that doesn't go bad after only a few weeks of use
Oh yeah, the other thing, when you put a steel core into an alloy hollow shaft, you're basically getting the worst of both worlds. The steel isn't in the position where it could add the greatest stiffness, and the alloy is now being used for threads, where it can more easily get stripped/damaged. I would love to see more motors with steel/Ti shafts, necked down to 3mm internal. The added space could be used to have a bigger BB in the bearings, and offset some of the durability loss we've seen with these super small bearings.
Solid titanium shafts with a C clip is the answer imo. Cheaper, stronger, smaller.
Yeah I totally agree, I think in a generation or 2 of motors, we'll see the retaining screw trend die out. Between the difficulty in removing them, and the need to compromise the shaft itself, plus the extra expense of machining the threads, they're just not great. It's funny to hear about the cheap thread locker being such an issue in china, I've had nothing but bad experiences with cheap Chinese stuff, in the end, I just paid the exorbitant price for a bottle of the real deal here in NZ, and never looked back
DossKat R5 is not 3x8x4, it is 4x8x3. Smaller balls are absolute crap, never ever use them, like ever! 3x8x4 are the same ball size as 4x9x4, just as durable.
Or solid titanium shafts with a bottom screw. Nothing says the shaft has to be hollow all the way through to have some threads just at the bottom. Just drill 5 mm in to the shaft and tap.
Looks good man! Watching now. I rewind motors as a side hobby in order to improve their efficiency, power output and alter their kv if needed. Lots of good info you posted. I should show you large spreadsheets of data and algorithms I use in order to derive my info before a rewind. Thanks for posting this video! Lots of good info and similar to a video I keep meaning to make/post. Appreciate all your good work in the hobby!
Enjoying your videos, and I have a quick question. and you seem to be the person to ask. Or if anyone can chime in here?
It's about the wiring type and size between the battery and ESC. It's DC but there is some ripple current flowing, as the pulsing from the ESC loading and unloading causes some voltage fluctuations. Understand that part...
Question is: What type of wire is truly best of this application? where do the electrons flow? on the surface? or is it all about the cross sectional diameter of the wire? Is the silicone "Cat Hair" wire with many strands better for this application, or are fewer strands better?
Why the difference between the silicone insulation as opposed to the normal rubber insulator on automotive wire, or marine wire? Is it about the heat? of course the silicone wire can take more heat, but being a better thermal insulator, it will trap the heat in the wire as well..
I have a friend who is a rocket engineer who seems to think that the hobby industry has got it all wrong, and that solid wire would be best to go between the battery and ESC. Just trying to find out the fundamental truth, and very ha
This money is pouring into Canadian construction, mostly underworld. Really hard for a honest co tractor to compete.
So are mult strand stators more efficient or single strand? If the single strand can handle heat better wouldn’t that be more efficient? Looking for longer run time?
As an American with a factory in China I can confirm everything you said about "Chinese" companies and more...
SKIDOOSH now I want to see you make a video discussing the issue since you live in the heart of the beast😀
The quick of it is a China company will release a great product for cheaper than they can make it and take a loss on the first few batches. Once it is "hyped" as being an awesome product for the $$$ and the market gets saturated they will degrade the product to cheap crap and double their money back. By the time everyone figures it out it is to late , but once the word gets out it is shit they will stop the cheap crap and re release the good one under another name and do it all over again.
I'd put you on the podcast. You'd be like a regular
The well known pump and dump that people will always fall for.
That's what landed me in China in the first place. We got several 100 great products and the next thing we new our stuff started failing all over America nearly ruining our reputation and biz. They have no scruples..NONE..I am constantly on the go traveling all over China to my suppliers pulling unannounced surprise visits.
Kabab FPV at its best right here!
Living in south est asia, i know perfectly this run for fake and copied products!
It's really something and some shops don't actually hide that the products they have are fake!
It's really a big cultural business here!
Have a great week and may the floss be forever with you :)
Perhaps a stupid question....but why are the magnets seperate instead of 1 ring?
you've gotta have alternating fields around the bell or the stator/esc doesn't know where the bell is.
Please do the Podcast, i would love to hear more in depth details about this!
I have 10 5in Floss 2 arms. Do you know can I buy top and bottom plate and hardware set from poroflip?
If i did understand, in the future we may get only one ring magnet in the bell when the manufacturers will be able to make it ?
Another question, why not full iron in the rotor instead of thinner and thinner laminations, cost, durability ?
Ps: the effect your were looking for with thick wires is the skin effect (translated from french, may be called otherwise in english)
I love your videos and this one in particular, very informative and moreover comprehensive, don't forget to...floss !
One big solid stator would work except that when you flip off the magnetic field of the poll, you're gonna get a bunch of residual magnetic field which will suck the strength out of the neighboring polls and also cause more resistance the next time that poll will need to reverse magnetize. It will heat up very quickly and generate less power.
the variation of the magnetic field induces currents inside the iron stator. these currents produce power losses. the stator is laminated to increase electrical resistance while keeping magnetic permeability.
if you want I explain it here czcams.com/video/hW1ew73Dnoo/video.html
Hmm ok i understand then better the constaints involved in between having still more layers for less Eddy currents and the need of insulation. Nice video by the way
Awesome video! Added it to my drone hardware playlist. I’ll be listening to this a few times till I take it all in. Appreciate your time spent on this
Many years ago I took apart a motor that was a direct drive capstan for a very expensive tape deck. It was being replaced because it's hours of use was near the specified limit. It still worked perfectly. One thing that really struck me about this motor was that it had no detectable cogging, whether it was powered or not. When I got it open, I found that the stators were slightly helical. By putting a piece of dowel rod and a ball bearing inside the sleeve bearing, I could get the motor half assembled. When half assembled it had noticable cogging. I wonder if helical stators would help reduce the vibrations in drones? Maybe your engineer friends might know more about this...
What you may have been looking at is a brushless induction motor which are actually more common than the permanent magnet motors we use. Induction motors typically have that twisted design. It probably wasn't a stator you were looking at either. From my understanding they're more expensive to manufacture and higher end. Or maybe it was and I've over extrapolated
@@Kabab the motor was an outrunner motor with the drive electronics attached to the back plate. I believe it had servo feedback. It could run at variable (but very low) speeds in either direction, and it did not seem to change speed with load. It maxed out at about 30 inches per second. I think the tape machine was used for scientific or forensic use. It had no record capability at all and it could handle everything from disassembled microcassettes to 1/2 mono reel to reel. It had a turret with about 8 different play heads to handle different widths and track counts. The playback electronics were external, you had to run BNC cables from the turret. There were different attachments to hold different kinds of tape reels too. The motor had ferrite magnets in the rotor in what I now believe was a halbek array (I did not know what that was back then). It weighed about 10 lbs and the tip of the rotor was the capstan. I do not know if that is consistent with a brushless induction motor or not. At 10 lbs it would make a really poor drone motor, but even with a stethoscope you could not hear whether the motor was powered or freewheeling. It has always amazed me that it was even possible to make a motor that smooth. The direct drive motor in my then-new Dual turntable sounded like a chainsaw by comparison.
@@jdrissel very interesting. There is VERY little in this department that's original. Nikola Tesla invented probably more than half of the basic tech that has made our modern world possible. Manufacturing has just gotten to the point where where we can produce half assed parts rather cheaply but the high quality stuff is still amazing and expensive to produce as it always was for hundreds of years. I'm sure you can figure out what exactly what motor is. If it's a true halbach array it's a pretty highly engineered motor.
Hey what if keep two 2306 motors side by side and switch the bells
For example 2 motors are named 1 and 2 are of same dimensions same kv or different kv I take the bell of motor 1 and put it on the stator of motor 2 and the bell of motor 2 on the stator of motor 1 could u please answer this question
Is there any sense going for Emax RS2205 2600kv at this point of tech development considering they are only $9.99? All other "better quality" motors costs mostly double. Or are those newer tech motors so much better? Motors are meant mainly for freestyle with quite a heavy 5inch quad. Appreciate your opinion.
Hey have you had a look at the efaw? Line? Particularly the 2407 stator size. What do you think about this motor on a floss 2 frame. No go pro and used as a daily flying acro? I know you're busy, your thoughts on rather I should go with the hyperlite 2207 or try this new 2407 draw, would meen a lot to me, I know you know your stuff.
Why the hell did they use titanium, its actually pretty soft compared to tempered steel that is widely available . I know its lighter but still.
Are you sure that thicker wire coating doesn't *help* with eddy currents?
I spoke with an engineering professor that suggested better care be taken to keep dust from getting inside the bearing. As the balls roll around, the dust is crushed and refined until it becomes very abrasive and the pitting of the ball bearings snowballs.
With regards to the aluminum shafts, a friend of mine found that after flying a sessions' worth of packs without changing props, the threads on the shaft were completely ruined. They had essentially disintegrated.
21:35 fillet to reduce stress concentrations
23:18 incorrect, unless you're referring to stiffness/weight
If your bearings are rusted on the outside, they're likely rusted on the inside too
This is a very old video by now. Very very old. Much is incorrect as I've learned. Also, keeping your bearings dust free is merely an academic task. In reality, it's impossible as you're crashing in sand and dirt. Eddy currents are reduced with thinner laminations.....they are literally 'thinner' for lack of an easier explanation. There are no aluminum shafts. Those would be awful. Only solid steel, hollow steel and both in hardened or regular. Also most recent motor bearings are 9mm OD now so the bearing issue is moot......goes on and on. Much has changed.
@@Kabab My T-motor F40 Pro IIs vibrate quite a bit, I assumed it was bad bearings. I'm not sure how to get you a picture of these wrecked motor shafts, YT doesn't allow links in comments.
@@dominiclallande it's unlikely to be as a result of the bearings as even crunchy bearings aren't that out of balance. It's more likely to be as a result of scrapes and dings in the motor bell or prop shaft. Oh yeah, that's what you meant by aluminum prop shafts. Yeah those are trash.
I have to watch this for a second time... So much info being spit at me!
I usually don't make comments like this, but this video is gold. Thanks a lot!
+1 for PODCAST!
Kabobcast.
I suppose it would be better to wind with copper tape instead of just one thread or multi thread, the same as that used in the toroidal transformer but in copper.
+David Mendoza Vargas seems logical but the electronics actually bunch up on the surface so they aggregate on the corners of a rectangle ribbon. At least this is what I'm told. Round wire is better.
Great info, podcast fore sure. Not sure about the BG product issue though. Obviously this is possible with an unknown brand but if your sticking to well known manufacturers like Emax, fatshark/immersionrc and the like then I doubt there is any risk. I bought the aokfly motors from the first batch and broke a motor every crash. Mainly bent shafts and base plates/mounts. They were smooth and powerful but no durability. The same punishment has never destroyed an Emax rs2205s. With over 200 orders from BG they have always replaced an item at no cost or thrown money at me. They've yet to cause me concern.
Definitely keen for that podcast
The laminar structure is to prevent eddy currents, which result in heat loss and reduced magnetic flux...
Just saying, I don't think you measured the length of the stator arms the same way for the 2406 motor at 12:10. You measured from the green bit to the tip while for the other motors you measure from the start of the windings to the tip.
Hamza Mohammad yeah I noticed but the end concept is the same. Wider motor, longer polls. My measurements are kinda pointless
Thank you for taking us on your knowledge journey lately. Also, kudos to people who comment on these types of videos too. Sometimes I learn just as much from the comments as I do in the videos.
My understanding was that the stamped steel stator sheets stacked together are in itself a laminate and the sheet thickness not the adhesive that binds them is what they are referring to when they speak of .0xxx laminate stator. So, i was supersized to learn it was actually the enamel adhesive they were referring to. I gues it makes sense either way.
Thanks for the great vids P.S i need to brush and floss come to think of it !!
I thought the same and I kinda think we're both correct too. Something may have gotten lost in translation but I asked that question over and over and got the same answer so I'm assuming that's what it is...?
Early processing squad!!
make the podcast dude, im super interested. its a bitch to do your own research, and with the fact that you know people on the "inside" it makes it that much better. please do it!
I've been waiting for a technical podcast, one where you can listen to educated people have interesting discussions, giving insight for all the components that we use. I just happen to have a particular appreciation for all the details we often ignore in the way our quad's components are made :)
The single best video i have watched in years! Respect! Alot of info... but most importantly.. alot of reference points for me to go and research and learn even more! basicly all you want to learn about motors lecture!
Yes!! research!
NIce job. Interesting insights into the Chinese culture. I suspect change is coming on that front.
Too bad about Bangood, they used to be pretty reliable, but it's been a while since I ordered anything from them.
Lately I hear a lot of people bashing them, Now I know why, from what you say, things have changed, and NOT for the good. Too bad.
The upside is that recently there's a lot more places in the US to get your Quad parts, and the prices are on par with Bangood. I've not received any fake goods from any of the US sources, and prefer to keep by business here whenever I can. That makes the loss of Bangood as a supplier no big deal.
Thanks for the heads up, and again, great job in 1 take.
Tech comment:
As an engineer I would like to warn folks that aluminum threads and aluminum nut are a formula for disaster, they GALL, which is a technical name name for cold welding, and it's about as bad as it gets. Once galled, something is going to break.
You can't tighten OR loosen the galled nut. It just stops. Bang, right there. (It also happens with stainless steel on stainless steel usually if assembled dry (no oil or grease), and it's not from overtightening, it happens with finger tight fasteners, but overtigntening can break thru the lubrication film and bring it on. It happens because of the way the metal molecules interact, and that's a physics lesson, and over my head. I've seen it happen too many times to count, it's the bane of auto racers using aluminum hose fittings. ( I used to drag race in another life)
On the 3B (BBB 2207) Motors (or any aluminum thread motor), just use steel nyloc nuts, a touch of oil (or even better anti-seize Vaseline works in a pinch) and be careful not to overtighten them and they should be fine. The upside is the steel nuts are MUCH cheaper and don't weigh enough more to notice. The Underground site says aluminum, but also says the shafts are titanium, I'd imagine (hope) the motors are supplied with steel nuts, if not, then save the alum ones for your other motors and get some steel ones to use with the BBBs.
Steel shafts use Alum nuts (Steel OK) but on Aluminum shafts use steel nuts (never Aluminum). Titanium is OK for either if you don't mind 7 bucks for a nut that saves you .2 grams
Thanks for the sale heads up and link to Underground, I may order a set of 3Bs when they are back in stock
Scott Marshall that's why I hate aluminum shafts. But it's not a big enough issue for me to pay like ~$3 more per motor.
I'm giddy about the BBB motors too... Also slightly concerned about what grade of titanium can actually bring that cost down to a $3 delta per shaft (though to be fair, all my CNC mill/lathe experience with titanium is for satellites), to the point where I keep coming back to the old RS2205 EMax motors as being actually not garbage - big air gaps, N50 rectangular magnets, but they take a beating, spin smoothly, and handle 5S like champions.
The T-Motor Air40 motors have an aluminium shaft and were supplied with aluminium nuts. I found this out after twisting the tops of three of the shafts off trying to remove the nuts on brand new motors. Luckily there was still just enough shaft to tighten down a prop with a steel nut. I am definitely not a fan of the aluminium shaft.
May be a stupid question , Is there a reason why they couldn't use a magnetic ring instead of individual magnets? What sort of issues would it cause if any? Or using large arc magnets that would only require 2 or 4 magnets to cover the I.D. Of the bell?
Dixie9mm not stupid. It's because they can't create a strong enough magnet in the ring. And the whole ring can't be one magnet because there need to be alternating polls to push and pull against.
Dixie9mm more magnets means finer control of the bell location
So a larger gap between magnets could make more power? I'm sure there is a point diminishing return in there somewhere. But a tight gap between magnets means smoother motors but could lose power? And they make up for it with stronger magnets? Among other variables, tighter laminations etc....?
Great video, not even a bit bored during the lenght of it. Packed of info. Thanks
What do you prefer for freestyle flight 2307 or the 2405. I'm interested in a build using one of these motors. I built a floss with 2306 emax motors which I love i get a lot of electric noise manifested in my video feed. Do u think installing a cap on power leads would help this problem?
Matthew Jordan it could help or you could just have a motor mounting screw that's touching the windings....
For the "bending the shaft" part: when you look at a punctual bending you are not facing momentum but shear force. Thus a full shaft is much more resistant than a hollow one (since shear force resistance is proportional to the section's area of the shaft)
Yes this makes sense except that you can bend a solid shaft easier than a hollow one on these motors. A hardened solid shaft is strong enough not to bend however.
@@Kabab ok that is strange. Maybe they whent for a too much thin wall for the shaft.
Still, if the bending happens in that particoular point (con ection to the bell) is definetly shear force doing it. If instead the bending happens in other spots I really can give you no explenation other than the one above.
Bob who makes the hyperlite 2307 and 2405? These are not brotherhobby motors right?
steven two companies make them and use many of brother hobbys suppliers of parts. So it's very similar to BH motors
Kabab FPV Must be top secret lol. I just picked up the 2405 2722 for a floss 2 and I'm extremely impressed! I've tried the 5046 cyclones and the 5050c cyclone bi prop so far and the 5050c feels and sounds amazing! I honestly can't believe I can get about 4 min on a 1300. Weight is 290g dry.
I really like my 2400kv T-motors. But trying the hypetrain 2450kv to see how those are. T-motor being the OEM is a nice touch also. What do you think of the hypetrain motors and T-motor pro 2 2400kv motors. I have a feeling the kv isn't high enough for you? Thanks so much for all the info. I think some of it sunk in
The kv is fine, I just don't think they're anything special at all. Not even a little bit. It's just another motor with a top shelf price tag and some marketing. They're fine motors, just not all that different than comparable motors.
now im not so sure about getting new motors from banngood....
i thought of getting those bbb motors but their kv and amp draw is kinda scary, how much flight time did you get with the 2207 bbb motors?
Don't worry about the kv. Amps is determined more by your AUW and prop.
Kabab FPV around 500g with batt, also I ordered the new dal t5040c you suggested
so it shouldn't be that bad right :P
By my pocket calculation, should be pretty decent, unless you're spending all day at WOT. 5x4x3 class draw, even on 550g quads and junk batteries will keep you in the air for 7m if you're being a patient llama.
hey sorry, irrelevant question but im currently in the process of assembling a quad (i.imgur.com/sGTwUzV.jpg pic related) together and had some wraith 32 50A ESCs laying around, i know they are overkill with me only running 5 inch hypetrains but is there any benefit to running these over the 25A variant?
You can run 8S. That's the benefit :-D
I have been looking around 4h for this informatin. I am glad i found this video. Thank You
The latest motor stuff I'm going to be announcing in a couple months will be very interesting...this video is very old by now and some of it is not quite accurate. A lot has been developed since then...
Bob..thanks for all this detail. That was the most informative motor education I’ve ever heard. The business view was amazing. Thanks!
Enjoy your intuitive take on the optimization problem that is motor design. Would love the podcast if possible :)
aluminum oxide is not really rust.
it is minor.
but does 3wires not meant 3 times more enamel, because the thinckness is equal an thinner wires have a higher surface per crossection than thick wires?
Probably there is an optimum between surface effect and less copper per available space, but if multistrand is clearly better?
yes, this is very debatable.
I think the advantage of the multi-strand, is that it will pack better around the stator, meaning that you can get more copper on the stator. The total power of the motor is proportional to the volume of copper on the stator.
That's not to say I'm personally favouring multi-strand though. These quad motors are operating in a very harsh environment; imagine the stress they suffer when you suddenly freeze a motor during a crash, with full current applied by the ESC. I think the added cooling benefit of single-strand is preferable - definitely IMO.
12:40 - Multi-strand vs larger single strand winds.. all other things being equal or identical; motor mechanicals, wire/copper quality, plating type/quality, enamel, and equal wire volume (pi*r^2 x3 or pi*r^2 x1)... the single strand wins every time and here's why..
A multi-strand motor on A/C does indeed have an advantage due to the increased surface surface area, but that advantage doesn't last long.
Many of those strands are packed densely into a unsightly wad and are unable to dissipate heat as efficiently. The inner strands have no exposure to passing airflow and radiate their heat outward into other wires, as heat builds resistance increases causing higher amp draw, even more heat, less power production per amp and less efficiency overall.
Also, all of that stator heat-soaking can/will compromise the cheap home-brew sleeve adhesive used to glue the stator to the base.
I've had several stators on multi-strand motors (one specific brand is a repeat offender) rotate on the base, loose timing, get real hot, and fail.
I've never had a single strand stator rotate on its base.
Solid strand wires in quad motors have direct access to airflow resulting in less heat build up, better sustained efficiency, higher amp capabilities, faster recovery from high amp draw moments (punch outs, etc), doesn't heat-soak the stator, adhesive, and magnets as badly... and all of that trends across multiple packs run back-to-back. As a bonus, solid strand is more durable and looks better.
Look, these things are expensive and we beat on them, the lightest weight best performing is rarely the best for freestyle use... buy motors with single-strand, thin stator laminations, good bearings, thick(er) titanium shafts with C-clips (if you can find them), thick(er) bells, meaty bell hubs, curved N52's with a airgap that'll tolerate some grit/dirt/debris and impact flexing without binding up or knocking magnets loose.. from someone who also sells replacement bells..
When you find that motor, buy enough for several quads, buy spares, and don't chase the latest-n-greatest with someone's name on it..
fwiw.. the above info comes from my own hand-winding of many MicroDan 2505 and 2510 motors with all sorts of wire, turn counts, both termination types, all tested for amp draw and thrust using a regulated power supply.
See gobrushless.com if you want sore finger tips and a headache.
I prefer single strand just because it's more durable. The debate goes both ways forever however. At the end of the day the difference isn't detectable to me at least.
I would definately listen to your podcast!
Bob thanks for the Banggood heads up. While I very very rarely order anything from them anymore and when I do its misc crap that has no brand name attached to it . That info will really help steer people's decisions.A clone is one thing a true replica is where I personally draw the line. Anyway great video and bring on the podcast :)
While you're not a professional expert, you have put in the time and effort to learn this stuff, which has made you a layman's expert and stating anything other than that does you a disservice.
'I don't really know what I'm talking about'... Uses technical terms and reasoning like a boss. Lol.
BTW, Loctite was purchased by Henkel corporation in the 90s. Was it ever owned by 3M?
When using multiple wires it reduces losses. You can use litz wire to do the same. The iron around the outside helps guide the magnetic field. The field travels more through iron than air and iron works kind of like a wire for the magnetic field increasing the strength.
Interesting and informative. Good Job Bob! I'll throw this in: No manufacturers and very few motor winding hobbyists use a winding technique known as Zig-Zag DLRK. I exclusively use Zig-Zag DLRK when I rewind my own motors, with either delta or wye termination. I think it is easier and neater than standard DLRK once you learn it and do one. It may also be more efficient based on what I've experienced. Shall we bring this into the conversation? I've got winding diagrams, tests and pics of motors I've done (years ago at this point). You know where to reach me. Later! :)
The conversation is never ending...
Ok so with all this info what is the best American made motors really curious if there is eny ??
+Andrew Bright I'm not sure any miniquad motor is made in America. If it were, it would probably be pretty expensive.
Can you do a comparison of the Finx23 and 30 by ZMX? Also the pros and cons of Taller vs Wider stator motors?
Also, your videos are very nice!!!
Cheers from the Philippines 🇵🇭
does the iron content matter or is it the iron content wrapped in copper wire?
You want the maximum iron while still allowing room for the wires to be wrapped.
The two ones, more iron allows more magnétic flux (1), the copper plays in two ways, more copper (surface) results in less electric resistence (2), and more windings let you do the same job with less current(3).
1 - en.wikipedia.org/wiki/Magnetic_reluctance
2 - en.wikipedia.org/wiki/Electrical_resistance_and_conductance ( resistivity and conductivity)
3 - en.wikipedia.org/wiki/Magnetic_circuit (MMF)
Note - one winding with 3 wire conected in parallel, doesn't count as 3 widing.
WELL DONE Sir that was Verrrrry Informative BUT! I had to have a coffee break, but well done
So much wrong with the magnet parts dude.
Magnetic fields are only reflected back under super-conduction (meisner effect), the closest in normal everyday situations would be diamagnetism, which is too weak for all intents and purposes. Thinner stator laminations are useful in that they reduce the eddy current losses, but only if the thickness is is larger than the magnetic penetration depth. ANy thinner and you will cook the laminations (also you don't pack more iron in the smaller the laminations, quite the opposite actually since you will have that thin gap in between the plates which reduce the total volume. But the silicon-steel laminations also has a much lower hysteresis energy. The only reason for thicker wire is actually the lower resistance, but you have less windings then. Also you have more eddy losses in thicker wires. On thinner wires you also have a less efficient coil since the individual windings are further from the ferromagnetic core which will reduce the "captured" flux. Also the thinner wires will increase the inductance (if there are more windings) which will influence the choice of the signal generator you are using.
So all in all its a continuous game of trading trade-offs (lol) to try and get the best performance and efficiency (not necessarily the same but frequently overlaps to a large extent).
Loved this video. What an eye opener, since this subject matter is new to me.
I see that this video is 6yrs old... I'm doing a build and this video came on in the background and man this must of been your tweaking days. sounds like your all hyped up on something...
it was just funny how fast your talking in this vid..... Thanks,
🤣 na. I just try to get the info out ASAP so the video isn't 3hrs long
Keep um coming!!!
It should be apparent your style is much appreciated!!!
Disregard my last Discord post :)
Your channel is awesome... please keep on sharing incredibly interesting info with us!!
Which motor do you recommend to replace from eachine 2206 Wizzard X220S? BBB 2207 or AOKFLY 2306? Both are under 15$ and that is the requirement. 4in1 30A ESC is enough for BBB 2207 or AOKFLY 2306?
Thanks for all the interesting concepts!
Which has more torque. The hyperlite 2405 or 2307? Or maybe the better question is. What is the difference in performance?
HYEonDEATHROW depends how and what you're using it for. I personally prefer the 2207 for all things 5" and 4S. The 2307 is an incredible 6" star. The 2405 did not perform well for me at all but people are liking it a lot some how. We're making some size variants for direct comparison testing.
Yes do such a podcast. I find this topic super interesting!
Thanks for share your knowledge and the things that you learn, please upload the podcast i want learn more.
You measured the stator length of the third motor differently than the first two.
Bill Roberts yeah I know ...but you get the idea
I will buy a bunch of those CMX motors.
More videos like this please and a podcast would be great!
Great. It was like taking a brushless class 😊
Please do this podcast! I would love to learn real facts about our hobby. It’s all so interesting!
But what about cooling, isn't a bigger airgap and less windings better for cooling?
less winding means higher kv and more heat generation from increased power draw. No matter what, a tighter air gap is always better. Better for all aspects of the motor function.
DId you test Egodrift Motors? They are supposedly one of the few motor producers (aside from BH and Sunnysky, ha i've even got some 2212 from them for my Discovery) They are like 5 Minutes down the road from our newest spot. I meant single strand by lesser windings, so more cooling area and no block of tangled 3-strands
Really nice information which no one sadly has or gives 😂
no the thinner multi strand wires would eventually have higher resistance than compared to that of thicker wires.
multiple strands are supposed to have the same overall cross sectional area but more surface area. Apparently the electrons travel along the surface area and so having more us supposed to mean lower resistance. At least this is what the general theory is.
Yes actually I was wrong, but the overall weight of the solid wires would be drastically lower. Almost equaling 0.453 grams/feet. On another note, I recently purchased the Hyper lite 2405-1922kv motors. What do you think about that? Do they stand good chance for longrange/semi freestyle?
it sounds like from what you've said, using the BLHeli Suite to reverse motor direction is better than crisscrossing the motor wires. Do you agree?
+James Grow well I've never heard or seen any issues work braided wires but it does make sense. I wouldn't expect just one crossover to matter. I always use blheli anyways because I don't like messy wires.
Do you know if the optimal magnet thickness is proportional to the length of the stator arms?
Another thing I'd like to know is why all motors are designed to have such high peak torque compared to what they can handle continuously without overheating. Logically that means the iron is nowhere near saturating when the coils are running at their continuous current rating. Continuous torque to weight ratio is what I'm most interested in for robotics, so I'd rather trade some iron for more copper.
Right. The answer to your observation is a skewed stator which will reduce peak output but increase average torque and power. Coincidentally, fettec has just made a sine ESC that matches the more natural response of the motor to inputs which would be a perfect match for a skewed stator for an overall 'smoother' running craft with more average range performance. This would be a very minor improvement on what we've already got however
"2500-2700kv recommended for 5" and 4S regardless of your quad. If it's heavy, use a shallow pitch blade like the DAL T5040C."
+Maurice Woelk anything past 620g auw is heavy to me. Most people might say that's normal however...
Awesome knowledge bomb. I learned first-hand about unscrupulous Chinese manufacturing with my first and last crowdfunding investment, the Kreyos smart watch.
You sure answered this, but. Why do you prefer high kv motors insted of "low" kv ones like 2300/2400?
+KANGI I've discussed this a lot in more recent videos. I think the one from last weekend. The one with the 'table of contents' in the title image. It has to do with handeling and the specific props that I prefer.