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Transportation Science

New Electric Motor Design Massively Boosts Power, Torque, and Efficiency (newatlas.com) 207

A Texas-based, father/son team raised $4.5 million in seed funding to build "a remarkable electric motor technology," reports New Atlas.

Long-time Slashdot reader Namarrgon writes: Linear Labs' impressive new circumferential flux motor design (video) uses four rotors [where other motors typically run one or two] and a software-reconfigurable, multi-coil stator, enclosed in a 3D magnetic "torque tunnel" to maximize efficiency even at high speeds. The stator can be configured on the fly by regrouping coils to use a variable number of overlapping phases simultaneously, producing full torque smoothly at low rpms without torque pulsing, or changing speeds with no change to frequency, current, or voltage, like an electronic transmission. An innovative approach to field weakening by gradually misaligning permanent magnets allows efficiencies to actually climb as speeds increase.

These features produce a highly compact motor with two to five times the torque density, at least three times the power density and at least twice the total output of any conventional permanent magnet motor of the same size. This also eliminates the need for gearing in many applications, reducing costs and weight while gaining 10-20% more range from a given battery pack.

Linear Labs has received 21 patents so far, with another 29 pending, and their prototypes have been verified by independent expert tests. Recently they received $4.5 million in seed funding, and are planning to build them into car and scooter prototypes over the next couple of years.

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New Electric Motor Design Massively Boosts Power, Torque, and Efficiency

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  • Duh (Score:3, Interesting)

    by Aighearach ( 97333 ) on Sunday August 11, 2019 @07:51PM (#59077572)

    I had this same idea last night, now today I learn I'm years behind and somebody already built it.

    That means there are probably tens of thousands of people thinking the same thing right now.

    • Re:Duh (Score:4, Interesting)

      by SirAstral ( 1349985 ) on Sunday August 11, 2019 @08:07PM (#59077604)

      Actually there are. There are loads of things already invented but not commercially available that people think up all the time. Additionally there are still a lot of things that cannot be patented because of prior work by people that though up idea centuries ago.

      More than often enough a lot of people have great ideas that will just never be realized because they cannot secure funding, do not even begin to know how to attempt to bring an idea to market, or will be doing something that someone else has already invented, but just not being used for the purpose they would be using it for. It happens, and it happens a lot enough to where there are duplicate patents being fought over in court to decide which ones apply, which ones should not be patents, and which ones are already offending someone else's patents.

      One of my ideas was pre-lit trees and net lights for bushes 30 years ago when I was a child. Sucks to be me but I bet someone already had a patent for that even back then.

      • It's OK, you need a flux capacitor to start the flux motor, and no-one has one of those yet.

        I've also been told never to run a flux motor past 140kmh (88mph), not sure why though.

      • Re:Duh (Score:4, Funny)

        by Oswald McWeany ( 2428506 ) on Monday August 12, 2019 @08:22AM (#59078560)

        Actually there are. There are loads of things already invented but not commercially available that people think up all the time.

        My great invention was the Wee-ja board. A large urinal cake with "yes", "no" and a few other answers on it. When you're drunk and having a piss you can commune with the dead at the same time. I've never got around to trying to make or sell it and most likely never will.

    • I've spent a few minutes occasionally pondering the relative value of an insightful observation, versus the likelihood of it being an incipient vision.

      7+ billion humans currently living, and 100 +/- billion modern humans since 50,000 BC (beginning of the Upper Paleolithic), appears to leave truly original ideas in the outlier region.

      That said, there is more than ever a special place for innovative thinking. Even in an era with unprecedented access to the observations of mankind, much of the wisdom is lost

    • I've had a few original ideas and innovations over the years. I usually learn they had already been thought of, or I did nothing with them and saw someone else present them. Some I have never seen.

      To name a few that come to mind :

      Parachute for entire airplane instead of occupants. (saw a prototype a few years after i originally thought of it)
      Washing machine and dryer in one. (not a stack , one machine, I realized manufacturers would have little incentive - if you want to get crazy it can fold clothes too -

      • Re: (Score:3, Interesting)

        by Ryzilynt ( 3492885 )

        I almost forgot the gem:

        Perpetual Puppy

        Everyone loves their new little puppy. But eventually that puppy grows into a gross old smelly dog. Well not anymore, he'll never grow old , and he'll never die. Welcome to perpetual puppy.

        How do we do it you ask?

        Don't worry it's easy. For a low monthly subscription fee you will get a puppy at the approximate age of your choosing, the gender of your choosing, the color and species of your choosing. Delivered right to your door in his very own crate. Colors leash,

      • I know everyone has these anecdotes, but I think mine is the best (and most annoying.) True story, not a joke. It was circa 2007 or so and I was looking at some enthusiast upstart project that was trying to get people to prepay so they could afford to build the things and I was like "Man, there are so many of these neat ideas out there that are in high demand... if only you could have an organization that would set up and supervise this process, hold the excess money in escrow, try to ensure that people wer
        • I was working on Facebook in 1998. Not "the" Facebook. I was working at a well known .com in was during the boom, before the bust.

          I wanted a place people on the internet could go to interact with one another socially. Originally it was to have message boards and a messenger, and it would primarily allow people to play games with one another.

          It never got past the concept phase, ran it by a few friends, no one was like " lets do it" so it never happened.

      • Washing machine and dryer in one.

        How long ago did you have this idea? Because washer-dryers has been a thing for decades. Pretty useful for small flats.

      • I've had a few original ideas and innovations over the years. I usually learn they had already been thought of, or I did nothing with them and saw someone else present them. Some I have never seen.

        To name a few that come to mind :

        Parachute for entire airplane instead of occupants. (saw a prototype a few years after i originally thought of it)

        Only needed when the wings are torn off (so not needed usually). When the wings are still attached you can lower your rate of descent much better than any parachute that might be able to slow the plane down.

        • by ibpooks ( 127372 )

          No there are a number of good uses for a whole aircraft parachute such as spins, low altitude engine failures or pilot medical emergency. Cessna had one available as an aftermarket add-on in the early 90s. Then in the late 90s Cirrus introduced one called the CAPS that is now their brand's flagship feature. They even keep a running gallery of "lives saved" from successful parachute deployments on their website.

          • good uses for a whole aircraft parachute such as spins

            That would almost have to have its own explosive inflation unit (like an airbag) in order to work, right? How would the parachute catch air while the whole thing is being twisted?

      • by AmiMoJo ( 196126 )

        Carwash for people. Seriously. Bathing is difficult for some people, due to health issues or disabilities. Personal hygiene is often compromised by those things.

        Scrubbing is the hard part.

        • by Shaitan ( 22585 )

          Those people would have trouble getting to and from a peoplewash. You'd have to go to them and they have a word for that, "home health."

          Now starting one of those which actually expended effort making sure the staff actually showed up and followed through on the appointments would be impressive.

    • I was too young and stupid to know anything about patents, etc. When I mean similar, I mean it was very close. The idea was to to have WYSIWYG in Windows that matched printer output. I built for my employer at the time in my 2nd job out of college. I don't think people where so much into patenting everything software back then.
  • by toonces33 ( 841696 ) on Sunday August 11, 2019 @07:53PM (#59077576)

    "Dramatically"?

    I guess 10-20% improvement with a battery pack is something, but only if it can be independently verified.

    • by ShanghaiBill ( 739463 ) on Sunday August 11, 2019 @08:08PM (#59077606)

      "Dramatically"? I guess 10-20% improvement with a battery pack is something

      In IT we are used to Moore's Law, Kryder's Law, etc. But in a field like electric motors, with centuries of history, a gain of 10-20% is indeed dramatic.

      If this turns out to be a real improvement, it will not only have a big effect on EV range and power, but also on air conditioners, which are currently the single biggest contributor to the growth in electricity consumption. A 20% boost in their efficiency would be big news.

      • When efficiencies improve it always means we use more of that resource (electricity in this case). See Jevons Paradox. The good news is that we currently need people to use more electric cars instead of gas cars, so it's good. Using more A/C isn't necessarily a good thing. Good for people, but it exacerbates the big problems we're facing.
        • Using more A/C isn't necessarily a good thing.

          Using more heat pumps is a good thing so long as they aren't total garbage; they need to be both reliable and repairable. But they can result in immense energy savings, and help move pollution out of town, and even reduce it.

        • Maybe, if all things remain equal. But, witness California electric demand reduction due to efficiency improvements over the past two decades as a counter-argument. (Costs of electricity tend to go up over time, reducing the incentive to maintain constant usage.)

        • by careysub ( 976506 ) on Monday August 12, 2019 @07:41AM (#59078502)

          When efficiencies improve it always means we use more of that resource (electricity in this case). See Jevons Paradox.

          A random factoid is a dangerous thing. The claim that efficiency improvements by themselves lead to greater usage (so obviously we save resources by being inefficient!) is not only not "always true" it has been very difficult to find any clear case of it occurring at all. Jevons, an economist in the mid 19th century, wrote a tome about this not based on actual data showing this to be the case but one entirely built on speculation.

          What he was observing was the rapid rise in the consumption of coal at that time (you know, the Industrial Revolution, with the steam engine) and concurrent improvements in steam engine efficiency (and other uses of coal, like more efficient use of it for heating buildings). But were these increases in efficiency the cause of rising coal usage, or was something else (like the many, many uses to which steam engines were being put by the revolution) driving this demand independent of how efficient they were? The latter would seem to be the case, and thus efficiency improvements were definitely saving coal.

          Have the recent advances in lighting efficiency led to increases in per capita electricity demand over the last decade? No, per capita electricity demand has dropped [eia.gov]. Didn't Jevons "prove" this can't happen"? No, he did nothing of the kind.

      • by Rei ( 128717 )

        You cannot add 10-20% range by improving the efficiency vs. modern PM motors, which have cruising efficiencies in the lower to mid 90s %.

        This makes me skeptical of all of the other claims being bandied about.

        • They are making a big deal out of the weight savings of no transmission. They don't claim motor efficiency gains, but overall range assuming a lighter vehicle and more efficient torque conversion.

          • The weight of the reduction gear is a minor issue compared to the constant efficiency loss due to having to go through the gears at all times. EVs are heavy anyway due to the battery.

            • That claim is odd anyway. Modern electric cars don't use gear boxes; and if the efficiency increases as speed increases, then you want to run higher in the RPMs and so you want a gear box to keep you in that efficient band.

        • Not directly. But if you no longer need a heavy gearbox, and the motor is smaller/lighter, you could also achieve some gains in efficiency. In theory, anyways.

          • The size of the motor is irrelevant unless you can make it small enough to fit into a heavy truck axle without major modification. This is not actually as high a bar as it sounds; new axle shafts are a completely acceptable requirement, and the differential cover on a good-sized axle is actually quite large. Then you could do a quality retrofit of OTR trucks, and buses. Their structure (ladder frame) and high dollar value combine to make them good cases for conversion. I'd love to do an EV conversion on our

            • by Mashiki ( 184564 )

              Most buses except school buses are already rear wheel drive and use a transaxle. Trucks on the other hand use front mount engines and transmissions to offset the weight of the cargo they carry or pull either in the trailer or box. The problem is when you reduce the weight of the engine and transmission gearbox, fuel, batteries, and so-on the rear load becomes unstable. Simply retrofitting these vehicles might not work at all without adding a way to automatically balance the load.

              You're looking at probabl

              • Most buses except school buses are already rear wheel drive and use a transaxle.

                No. Most buses don't use a transaxle. Most buses use a separate transmission and straight axle. Sometimes it's mounted in the rear, though.

                The problem is when you reduce the weight of the engine and transmission gearbox, fuel, batteries, and so-on the rear load becomes unstable. Simply retrofitting these vehicles might not work at all without adding a way to automatically balance the load.

                You put batteries up front. Done.

              • Most buses except school buses are already rear wheel drive and use a transaxle. Trucks on the other hand use front mount engines and transmissions to offset the weight of the cargo they carry or pull either in the trailer or box. The problem is when you reduce the weight of the engine and transmission gearbox, fuel, batteries, and so-on the rear load becomes unstable. Simply retrofitting these vehicles might not work at all without adding a way to automatically balance the load.

                You're looking at probably partial redesigns of the tractor itself, or even scrapping of the current design to the point where the trailer sits over the vehicle cab in order to center the weight.

                And you seem to be forgetting the weight of batteries offsetting the absence of a traditional engine/transmission.

        • by drinkypoo ( 153816 ) <drink@hyperlogos.org> on Sunday August 11, 2019 @08:58PM (#59077730) Homepage Journal

          They claim their effective torque range is broad enough that you don't need a reduction box. If you multiply that by the other efficiency improvements, it seems more feasible that they could see improvements like that over specific current systems. As far as I know, though, current hub motors don't have reduction gears either — and the latest ones which are built into the hub (with the disc that bolts to the wheel) produce a package which weighs about the same as a traditional front wheel end.

          It seems to me like hub motors are the future for most EVs, especially anything not intended to be "high performance". It's not necessarily going to provide the best experience even if they can keep the weight down (using inboard motors might still result in less unsprung mass when using carbon brakes) but it eliminates the axles, and they're a common point of failure.

          • Meh ... axles don't fail that often in mild performing cars unless they are just crap construction and/or made to be as light and cheap as possible. With all the motor and gear box savings, add another 4lb to the axle weight and those things will last forever.

            • by drinkypoo ( 153816 ) <drink@hyperlogos.org> on Sunday August 11, 2019 @09:30PM (#59077790) Homepage Journal

              axles don't fail that often in mild performing cars unless they are just crap construction and/or made to be as light and cheap as possible.

              I've replaced enough of them that I know that CV axles usually fail for one reason, the boot fails. Then the grease comes out and/or crap gets in, and that destroys the joint. It doesn't really matter what the performance of the vehicle is like.

              • by dotancohen ( 1015143 ) on Monday August 12, 2019 @04:47AM (#59078254) Homepage

                You will see far more torn CV joint boots on Hyundai i30s than you will on Subaru Outbacks, though. The Subaru transmission sits higher off the ground, and has a bit of frame below it. The Hyundais have the inner CV joints almost at the level of the oil drain plug.

                So there are design factors that dictate how long the components will last.

                • You will see far more torn CV joint boots on Hyundai i30s than you will on Subaru Outbacks, though. The Subaru transmission sits higher off the ground, and has a bit of frame below it. The Hyundais have the inner CV joints almost at the level of the oil drain plug.
                  So there are design factors that dictate how long the components will last.

                  Sure, but that has nothing to do with quality. Subarus are engineered to have more ground clearance because they are purchased by people who are more likely to need it, but Hyundai is able to offer a better warranty than Subaru because their cars are more reliable.

            • Not just failures though, but also the benefits of full independent control in at least three degrees of freedom. Hub motors are a huge opportunity, as long as unsprung weight is kept down.

          • So it is a vastly overhyped press release, touting efficiency gains over older engines instead of newer designs other people have already produced.
          • by cb88 ( 1410145 )
            Axles a common point of failure? My Acura had 250k miles on it before the CV joints showed any need of replacement... and they still hadn't fully failed when I replaced them... and that was on a 20 year old vehicle. Axles can be designed to last... the problem is companies like GM / Ford cost cutting in the product to pretend to be competitive.

            My dad's suburban has 240k miles on it... and the CV joints certainly aren't the first think on there that needs replacing lol. I'm just saying CV joints and axels ar
        • by vlad30 ( 44644 )
          If they were only talking about raising the efficiency of the motor then yes getting 10-20% doesn't add up but they are talking 10-20% more range out of the battery pack through a motor design that helps reduce other components/weight leading to energy savings in other areas.
        • They're only claiming 10-20% range increase after including mass savings from smaller motors, reduced gearing, etc. They do say motor efficiency is increased, particularly at speed, but I haven't seen hard figures on that - would that to be a much smaller percentage.

        • Wouldn't a cruising efficiency be least-relevant? Acceleration sucks down most of the energy in electric cars right now, and accelerating rapidly versus slowly can make the difference between a 40-mile range and a 32-mile range--even though the acceleration is only a few seconds of your total driving time.

          • Wouldn't a cruising efficiency be least-relevant? Acceleration sucks down most of the energy in electric cars right now,

            Acceleration performance is important, but as long as you have good regeneration performance, you get much of that energy back. The energy spent fighting gravity, drag and friction while cruising, however, is lost forever. Ideally, you spend most of your time cruising.

        • which have cruising efficiencies in the lower to mid 90s %.

          I won't restate most of the other claims, but cruising efficiency is far from overall efficiency. Acceleration and deceleration are a significant part of the weighted average used to determine overall efficiency and that's where a lot of the savings is.

      • by Dan East ( 318230 ) on Sunday August 11, 2019 @09:20PM (#59077778) Journal

        air conditioners, which are currently the single biggest contributor to the growth in electricity consumption. A 20% boost in their efficiency would be big news.

        It's very unlikely this will benefit cooling compressors or blowers. They operate at a single speed, so the motor can already be optimally designed to function at that exact speed. The entire point of this new motor is to provide better torque over a range of RPMs. The advancement is essentially to adapt the motor to the speed and the torque required at that moment, which varies as a vehicle changes speed, or when it begins climbing a hill and the torque requirements grow. Again, with most things like an electric fan, blower, compressor, etc, they operate at one single optimal speed, and when some threshold is crossed (the temperature reaches the desired level) they simply shut off entirely.

        • by smoot123 ( 1027084 ) on Sunday August 11, 2019 @11:08PM (#59077896)

          It's very unlikely this will benefit cooling compressors or blowers. They operate at a single speed,

          Funny. I just replaced my pool pump and furnace, and am about to replace my AC. These are my largest electric loads by far. The big thing in all areas now is selling variable-speed motors so I can run them slow when I don't need much action and at high speed when I need to move a lot of heat or water.

          The age of single-speed motors seems to be coming to an end.

        • by markdavis ( 642305 ) on Monday August 12, 2019 @12:07AM (#59077974)

          >"It's very unlikely this will benefit cooling compressors or blowers. They operate at a single speed, so the motor can already be optimally designed to function at that exact speed. [...] they operate at one single optimal speed, and when some threshold is crossed (the temperature reaches the desired level) they simply shut off entirely."

          Last week I replaced my entire HVAC system with a variable speed compressor and variable speed blower. They are not only more efficient, but offer more comfort, and are more reliable because they don't have to turn completely on and off over and over- it can run at partial speed much more continuously and adjust output as needed.

        • Most compressor motors today are variable speed, so there is an opportunity in theory. Unfortunately, the limits are more around refrigerants and thermodynamics rather than the motor/inverter combo.

          • Most compressor motors today are variable speed, so there is an opportunity in theory. Unfortunately, the limits are more around refrigerants and thermodynamics rather than the motor/inverter combo.

            So what you are saying is that variable speed motors promise to contribute to the increases in efficiency in cooling systems. Really odd that you are determined to put that in a negative light.

      • A verified 1% boost without exotic materials would be cool enough; motors are some of the most optimized things out there given over 100 years of engineering.

      • " it will not only have a big effect on EV range and power, but also on air conditioners, which are currently the single biggest contributor to the growth in electricity consumption. "

        Wouldn't they not also be great in (wind)-generators?

    • Well when you put it that way it doesn't sound that impressive, but if they said that about a battery I would be really happy, so if you can't fix the battery, fix the motor. So I'm still happy. Although from the article it sounds like Tesla had already been working on something similar.
  • by dimeglio ( 456244 ) on Sunday August 11, 2019 @08:52PM (#59077716)
    Just hope the royalties will be reasonable to help make EVs more affordable to regular folks.
  • by lkcl ( 517947 ) <lkcl@lkcl.net> on Sunday August 11, 2019 @09:08PM (#59077748) Homepage

    i've studied motor design, and have a colleague who has as well. the additional stators means doubling the number of neodymium magnets. neodymium refining requires insane quantities of boiling sulphuric acid per 1kg of neodymium, and in the locations where we, in the West, do not see it, they just dump it into the local environment:

    https://www.theguardian.com/en... [theguardian.com]

    the increased torque is also nothing new. for people who are interested in the technical details of an open hardware design, look up the LRK TorqueMax:

    https://www.aerodesign.de/pete... [aerodesign.de]

    the way it works is the use of a prime number of poles vs an even number of stators, requiring that the 3-phase field run at 6 to 7 times faster than "normal". this is how you get the "gearing" built-in to the motor.

    it means that the 3-phase field has to run at 40,000 hz in order to get the motor to run at 6500 RPM, basically.

    the other neat thing about it is that it is an "inside-out" motor, meaning that it is suitable for wheels, propellors and other tasks involving vehicles.

    • by blindseer ( 891256 ) <blindseer.earthlink@net> on Sunday August 11, 2019 @09:52PM (#59077812)

      the additional stators means doubling the number of neodymium magnets. neodymium refining requires insane quantities of boiling sulphuric acid per 1kg of neodymium, and in the locations where we, in the West, do not see it, they just dump it into the local environment:

      I propose that those of us in the West take advantage of the ample rare earth element resources that exist within our borders. We can do this in a way that does not involve the dumping of toxic and radioactive materials into open air lakes. This will require changes to regulations on the handling of this radioactive material that would still be safe for people and wildlife but not impose the high costs that current regulations require. Another remedy would be to impose a tariff on imported ores and devices that contain rare earth elements.

      One primary problem with mining for rare earth elements in the USA is that the thorium and uranium that is always present in the refining tailings is by law considered a weapon grade material. It is not anywhere close to anything that could be used in a weapon. Simply fixing this outdated definition may be all that is required to avoid having to source rare earth elements from nations like China that have such little concern for pollution and the health of their citizens.

      Because this leftover material contains thorium then it must be disposed of in a military radioactive waste site. It's not any more radioactive after being dug out from the ground than it was before. Disposal of this should be as simple as putting it back in the hole it came from. If this is for some reason a threat to the environment because it was disturbed then allow for disposal by some other appropriate means, other than being placed under constant guard by the military. Guarding this waste is completely nonsensical because if someone wanted this thorium bad enough then they'd just mine for it. I don't know why this collection of thorium is considered a national security threat as no one has yet found a means to weaponize it.

      We can't make China clean up their act on rare earth mining except perhaps through economic pressure. We can require that all ores and materials have documentation on being procured in an environmentally friendly manner, or we can mine this ourselves in a way that is non-polluting and simply put them out of business by not buying from them any more.

      Thorium could be a very valuable resource all its own, it need not be considered a waste product. Thorium can be used as fuel in a nuclear reactor for one. There's also a number of industrial uses for thorium. But because it is considered "weapon grade" if it is dug from the ground these uses cannot be legally investigated.

      I propose that instead of simply complaining about the problem we investigate solutions. This needs to start with a rewrite of the laws on rare earth elements and the actinide elements that are found in the ores with them. We need these elements for our modern society as there are no substitutions. I suggest we put China out of the rare earth element business by mining those elements where it can be done properly instead of continuing to buy them from China.

    • How much Nd and other lanthanides are we putting into landfills from discarded hard drives, earphones, speakers, small motors, and magnet toys? I am at least as worried about indium and gallium.
    • by jabuzz ( 182671 )

      You also can't massively boost efficiency of an electric motor because they are stupidly efficient to being with. A random cheap as chips motor will be >80% efficient to being with and a quality motor where someone has actually put effort into making it efficient is going to achieve ~98% peak efficiency.

      • They both have nearly identical peak efficiency. The difference is in the valleys (variable speeds)

    • additional stators means doubling the number of neodymium magnets

      These motors are smaller. Are you one of those people who cut a piece of pizza in half when you're really hungry and you think you can eat two pieces?

  • by joe_frisch ( 1366229 ) on Sunday August 11, 2019 @09:28PM (#59077786)

    It may be a good design, but without power and efficiency curves relative to other motors its difficult to tell.

    20 seconds into their video they show a graph of efficiency, where it looks better than a "conventional" motor, but they have a note that both have a peak 95% efficiency (which isn't visible on the graph). I don't know how that is consistent with 10% more efficiency.

    Is there any technical as opposed to marketing data?

    • The only way I could see that is if it reaches the 95% over a wider operational range(power and RPM speed), and thus an EV motor might average 80% as it moves in and out of its 95% efficiency zone, where this new motor spends 3 times as long in the zone, thus it averages 90% vs the earlier 80%.

      • TFA doesn't actually give numbers for any efficiency gains, which may only be noticeable in fairly selective ranges as you suggest. The "10-20%" gain is claimed only for "range", and only after taking into account mass saved from eliminating gearing etc.

  • Almost everyone in the marine transportation industry will be watching this very carefully. Shipping concerns are overjoyed with a 1 to 2 percent increase in fuel efficiency. Actually anyone that uses electric motors should be following this.
  • Whenever an innovation that increases the efficiency of motors comes along, check for any applicability to generators.

  • by guruevi ( 827432 ) on Sunday August 11, 2019 @10:50PM (#59077882)

    The design sounds and looks awfully much like a stepper motor, they have so much torque they can even hold the motor still even with external forces applied just by energizing a coil and they're indeed very dense for the torque they can produce. It's been way too long since I studied them but I clearly remember stepper variants that had multi-rotor (and multi-coil stator is just the definition of stepper). You can spin them really fast and stop them on a dime and when properly sized, they wouldn't skip a step (and if not, you could destroy them)

    The problem with stepper motors is both the cost of building them, weight and scaling up the controls, hence why we don't use them in large(r) motors because cost efficiency goes down the drain and the inductance in the windings for large motors would require larger controls than is practical.

    What it looks like they've produced is a 'better' (or let's say more detailed) controller for a stepper motor where they basically can put a number of coils in series or parallel on demand and some software to control that. You can buy 5-wire and 8-wire steppers already which depending on the software or hardware configuration you can have a higher/lower current draw for higher/lower speeds vs torque, this basically expands that idea to "more" wires which you can then switch the motor between a variably precise and torque-specific stepper motor or a very lossy servo.

    The theory has existed ever since steppers were invented and every 2nd year electronics engineering student has if not thought about it, had some evil professor that really wanted you to build a controller from scratch that can switch an 8-wire stepper to a 5-wire or 2-wire (for most people the various modes of a stepper are simply demoed in a lab) but the losses are so immense and the costs so great that the real-world applications don't exist.

    In the end nobody will want to put in one of these to drive a car if they can put in a servo, even if it's less compact, has slightly less torque at the low end and is less precise because it will be so expensive, suck up much more juice and heat up and be a pain to make the controls it won't be worthwhile. For cars especially, there is sufficient torque in whatever Tesla is putting in their cars right now.

  • by scdeimos ( 632778 ) on Sunday August 11, 2019 @11:43PM (#59077944)
    Looks like they've rediscovered the outrunner motor design.
  • by jimbo ( 1370 )

    Maybe this is what I need for my wheelchair, seeing as nobody wanted to do a LS swap for me.

  • by rew ( 6140 ) <r.e.wolff@BitWizard.nl> on Monday August 12, 2019 @02:27AM (#59078088) Homepage

    The marketing summaries here on Slashdot scream "BULLSHIT" to people who know a thing or two about motors. They must be thinking of "RPM/V" as "efficiency" to be able to claim an increase in efficiency while field weakening....

    However when you read the site of these guys: They know what they are talking about!

    Their system has two tricks. First there is some sort of electrical gearing involved. This does not increase power, but allows you to trade torque for RPM. So you could make say a 1kW motor for 4000 RPM, or differently configured in the factory a similar motor could produce that same 1kW at 8000 RPM (but half the torque) or at 2000 RPM (at double the torque). They can do this in one motor.

    In some cases this can be an advantage. If you need say x torque at 6000 RPM, but 2x torque to get started at 0RPM, you need a traditional motor that can deliver 2x torque almost up to the max speed of 6000RPM. So you will effectively be buying a motor that has twice the horsepower that you need. That's wasteful. This invention allows you to do that with one motor that's twice smaller because you're not buying the extra horsepower.

    I'm not sure that they can achieve 2x power density "in general".

    The second trick is to do passive field weakening. This is a trick to get a motor to spin faster than what the normal motor constants would allow. This allows a further increase in RPM at the cost of more loss in torque.

    As far as I can see, the motor driver for this motor is going to be enormous. And enormously expensive. Where a normal three-phase-motor driver will require 6 switching elements (mosfets/IGBTs). And each driver-pair must be driven by a PWM-capable timer in your microprocessor. These motors require a big multiple of these driving elements and microprocessor resources....

    • by dlang ( 6158732 )
      In practice it may not be as bad as you think. microprocessor speeds are dramatically increasing, so you shouldn't be that worried about them (look at the teensy 4.0 that was just released) as you scale up, you either need much bigger switching elements, or (more commonly) you start working to have banks of switching elements in parallel. If you break up these banks to let the individual elements get switched independently, it sounds as if you have the independent control you are needing.
  • by sad_ ( 7868 ) on Monday August 12, 2019 @05:41AM (#59078348) Homepage

    "Linear Labs' impressive new circumferential flux motor design"

    did they also make a flux capacitor to get along with it?

  • Generator (Score:5, Interesting)

    by Apostalypse ( 4570243 ) on Monday August 12, 2019 @07:23AM (#59078476)
    Does this design work in reverse as a generator? If so, a gearboxless generator would be bigger news than a motor. The gearbox is a major source of failures in wind turbines, and it would dramatically decrease the complexity of all types of mechanical generators.
    • Does this design work in reverse as a generator?

      I don't think anyone could be taken seriously if they proposed an EV motor that didn't permit regeneration.

  • Never are the downsides mentioned. What is the balance? There are always some balancing downsides to things. Cost? Complexity? Is it repairable? Besides, the Chinese Communists will just steal it anyway. Expect it.
  • It must be real, they have an animation!

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