Tesla's Rare Earth Free Motor // Niron Iron Nitride or Ferrite Magnets?

At Investor Day, Tesla teased a rare earth free motor. This has led to spculation about Tesla partnering with Niron for their Iron Nitride material. However, I think think humble ferrite magnets may actually be a better option. Let me know what you think in the comments below.
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Timeline
0:00 Introduction
01:00 What is a Rare Earth?
02:20 Why Remove Rare Earths?
03:09 Why did Tesla Use Rare Earths?
05:24 Niron Iron Nitride Magnets
11:42 'Tesla' Magnets
14:20 Tesla Ferrite Motor
23:45 Summary
Intro Music by Dyalla: Homer Said

[@thelimitingfactor]

1) Why didn't I talk about Alnico, etc? Because there are several other magnets that could be used and several different motor designs. It wouldn't have added value to walk through all the potential permutation - of which there are hundreds. I walked through my logic so that the viewer could take those variables and apply them to other technologies. Teach a man to fish. 😉 2) There's a lot of people commenting that Tesla will use an induction motor. But that doesn't align with what Tesla said: From the Investor Day Presentation: "we have designed our next Drive Unit which uses a permanent magnet motor" Why did they make that decision? Efficiency probably. I presented the worst case scenario here at 93% efficiency. That's the minimum for PM motor, whereas its the ~maximum for induction.

[@Crunch_dGH]

Thx so much for this clarification. Can’t wait to see your report on how this definitively pans out!

[@surferdude4487]

Why not Alnico? That's easy. the "co" is for cobalt. For reasons already well known, Tesla is eliminating cobalt from their products. Your assessment is dead-on and well discussed in this video. If Tesla is sitting on a new magnetic material, that would really be something, but there is no evidence of that. The feride magnets will be good enough.

[@steveperreira5850]

Dear Jordan: I agree with you totally. I think you have the best bet with the Ferrite. Done a fair amount magnetic design as an electrical engineer design in contactors, motors is a little more sophisticated, but there are tricks to the trade and it is not insurmountable to avoid demagnetization with clever design. All of this is just great. Thank you, Steve

[@richardereed9205]

There is a phenomenon known as the Flynn parallel path technology. It uses three magnetic fields in an alignment that permits a 4X multiplication at one end. Using that technology wisely in a motor will allow a 4X improvement in the net usefulness of a ferrite based rotor or stator. Boeing was so impressed with the possibilities that they bought a licence to use it. QM Power uses the technology to make the most efficient motors available to date in many applications.

[@andrewkaiser7203]

Tesla is also moving to a 48 volt system. How do you think that figures in when it comes to the motor design?

[@kyleronen]

Why has nobody offered this man a contract for an EV special on a major platform? Jordan, your videos put the educational platforms to shame with how well you produce them. Keep it up!

[@khuo0219]

The market for this type of knowledge is small, it shouldn't be, but it is. it is long, not dumbed down, and not made for TikTok

[@Martinit0]

KZbin IS a major platform

[@formes2388]

@@khuo0219 There is potentially more information to be discovered about the universe that we do NOT know yet as a society, then all the information humans have discovered about the function and way the world and universe works so far. If we break this down - there are fields of knowledge where to master the entire field of study would take multiple lifetimes of just study - not generating anything new. KZbin as a platform provides a way to create content, find the audience, and share with people. It is a way that people can discover an interest in something through happen stance. However, very few people are needed to make new types of motors, or research materials relative to the amount of people you need to produce commercial product. What this means is the cross section of a given population likely to be interested in this subject AND pursue an abundance of knowledge actively is going to be relatively small. Ya, it's interesting. But it's niche.

[@_Mutineer]

Hi Jordan, as usual, a well-researched and interesting topic. I always get excited when I see a new drop from you because I know that I will learn something new that day. You occupy a rare position in the Tesla community, IMO, as well respected as Munroe and always well referenced on some "secondary" Tesla channels. So thanks for the drop and keep 'em comin'. Congrats on passing 100k subs. For a technical channel, that is impressive and indicative of the quality of your content, onward and upward.. Cheers from "The Great White North".

[@propelegant]

An interesting design feature that might contribute to a more efficient motor is the Holbach array. Magnets in Synchronous reluctance motor seem to be arranged in a Holbach array which allows the magnetic force to be focussed in one direction or another. An explanation of Holbach array is worth a video of its own. There is an arrangement of small cuboid magnets that are bonded together to form a string of about six magnets. Each magnets polarity is rotated to steer the magnet force to one side only. This in effect doubles the strength of the magnets for the same weight.

[@derpeter4356]

The only youtube-channel that i put speed on 0.75x speed to be sure to get all informations. Insanely good videos. Greetings from Germany!

[@thelimitingfactor]

💕

[@juliatruchsess1019]

The most soothing voice EVER! I could go to sleep listening to any of these videos (not that they're boring!)

[@thelimitingfactor]

Lol, a number of people use them as a sleep aid

[@sagetmaster4]

Was just looking for a good video on this topic last night. Glad you just finished!

[@georgepelton5645]

Jordan, Thanks for another interesting and well researched video! You make a good case for Ferrite magnets. GM used Ferrite magnets in the Gen 2 Chevrolet Volt (MY17-19) for one of its two electric motors. It was a bit less efficient, so they only used it for MG-A, which is primarily used to generate electricity from using the engine. MG-B, which is primarily used to power the wheels, used rare earth magnets. This allowed maximum EV range, with a minor hit to fuel efficiency when in “extended range” mode. GM published an SAE paper on the Gen 2 Volt drive unit with this and other details. However, I do hope Tesla does not sacrifice motor efficiency in their Gen 3 product. Cost saved on magnets, and then some, would be spend on more battery capacity to achieve the same range.

[@josephvanorden3782]

Jordan, you taught me a lot in this video! Professional and well done. I thought Tesla getting rid of rare earths was amazing, but I never thought deeper about how they would do this. Thanks for educating me!

[@frank2you]

Thank you Jordan, great explanation again.

[@pauljones9150]

I love the sources, the thought and analysis and the deep research put into these videos

[@joestafford6529]

Awesome as always. I have to digest a bit and then watch again to try to absorb all this info. Thanks!

[@TomTom-cm2oq]

I love listening to you! Thanks for the clear and concise explanation with no “ummm” or “you know” fillers. Awesome video!!!

[@thelimitingfactor]

😁🤜🤛

[@greghwang3289]

Nice approach, reasonable conclusion. Thanks for the clip.

[@crospend]

a lot of work put into this...well done!!

[@thelimitingfactor]

😊 Thanks

[@rattusfinkus]

Fantastic work as always

[@LabPsycho]

Brilliant thought process, lucid arguments and compelling analyses. Very well done!

[@thelimitingfactor]

Thanks man!

[@FiDelZarlar]

Fascinating stuff! Tks Jordan! ❤

[@synx6988]

this is your best video since the battery day videos. Well done!

[@slwiser1]

I enjoy your presentations, the best on the internet.

[@jbrownson]

Excellent explanation as always, thanks

[@TeslaSifuAndy]

such good research! I also love how you allow room to be wrong unlike other commenters. You are just top notch and always insightful

[@thelimitingfactor]

Thanks Andy 😊

You're such an amazing channel to research and understand the new world coming! I'm really grateful for what you do! All the best!

[@thelimitingfactor]

You're most welcome and thanks for the kind words Diego!

[@iamcomcy]

Very thorough investigation! Always on point!

[@garrygballard8914]

Excellent educational video, thank you.

[@johnthomas5806]

thanks you Sir for your insights about this matter..

[@avgjoe5969]

Very nice analysis!

[@kwinterburn]

Another thing that is worth remembering is Ferrite is temperature related magnetism and it's a heavily temperature controlled environment, and magnetic decay can be reversed with a little complexity because that's how it's made, I would also examine Alnico to be honest, there are many ways to skin a cat,

[@thelimitingfactor]

Yeah, lots of people suggested that too. Not worth covering it. I feel like the logic provided here works for any magnet.

[@surferdude4487]

The "co" in alnico is for cobalt. Tesla is eliminating cobalt from their products.

[@budgetaudiophilelife-long5461]

🙋‍♂️ AS ALWAYS JORDAN,WE APPRECIATE ALL YOUR EFFORTS AND SHARING IN WAYS WE CAN UNDERSTAND 🤔🤗💚💚💚

[@williamwoo866]

Thanks Jordan I knew zero on magnets but I now appreciate how motor materials are so important-> you are right in designing a car from wheel to aerodynamics to compensate the less efficient motor yet adequate to the final product.

[@kierrsun]

Sheeeeesh what a quality video 🤌🏽 Well researched from the science to the economics, non overtly poetic, with just enough clever opinions sprinkled.

[@thelimitingfactor]

Thanks man!

[@tomcrouchman]

Great video! Thx!

[@Clark-Mills]

Great info well presented as usual, thanks!

[@thelimitingfactor]

You're most welcome Clark!

[@MrFoxRobert]

Thank you!

[@getiingtubed]

Excellent analysis

[@randycarlson]

Hi Jordan! You may be overlooking the magnetic design options enabled by the carbon fiber over-wrapped rotor. Because the carbon overwrap supports the centrifugal loads it becomes possible to employ a magnetically isolated "pole shoe" structure between the magnet(s) and the rotor external diameter. This is a key factor in obtaining the very high performance seen in the Plaid motors. A magnetically isolated pole shoe would also allow "narrow, shorting air gaps" in the magnetic circuit to shunt excessive fields (as seen at high motor drive currents) around ferrite magnets, protecting such magnets from demagnetization. A design that utilizes more of the flux available from the ferrite magnets thus delivering higher torque than conventional ferrite motor designs and higher efficiency should be obtainable by use of the carbon overwrap. Owing to the lower flux density of ferrite magnets compared to NIB magnets, the magnetically isolated pole shoe will offer greater benefit to the ferrite magnet design. Ferrite does look to be the logical choice for Tesla as you nicely explained. I suspect however that the Tesla / SpaceX materials team will be looking to tweak the ferrite formulation (there are small amounts of stuff other than iron and oxygen in there) to optimize it for Tesla's application - similar to what was done for the aluminum alloy developed for the gigacastings. Best, Randy Carlson

[@thelimitingfactor]

Thanks for your thoughts and thanks for breaking it into paragraphs Randy!

[@nftsasha]

THANK YOU!!

[@ch94086]

Wow, fantastic production! I really appreciate the quality of your video and efforts made. The graphics are great (I often have to rewind and pause since they are so relevant), and I also appreciate the great organization of the presentation. It's really clear, I learned a lot about the technology (enemy though I follow it), and thought your speculative assessments were well founded and explained. I understood and agree with you as far as I know. I just wanted to thank you for the great effort you made to create an exceptional presentation. There are many KZbinrs talking about clean tech, some babbling without any concept of economics or reality, or are just fan-boys. Your channel I think tops the crowd, with great quality and informative value.

[@thelimitingfactor]

Thanks for the kind words Carl! Glad to provide useful information for people 🤠

[@laurencemcguigan2225]

Thank you i have had trouble sleeping lately but i found your video and i was asleep within ten minutes 😂

[@thelimitingfactor]

😂

[@TechViewOpinions]

Great analysis. 👍

[@devo237]

I appreciate your hard work and always love your well researched videos

[@thelimitingfactor]

Thanks! 😊

[@gospelofthomas77thpearl22]

Amazing. Thanks 🙏🏼

[@hornethurdler]

Thanks!

[@SteveWindsurf]

Great presentation,, thanks- Some other points: Ferrite cored motor, will be of less torque. OK, so it could be bigger, or run faster for the same power delivery. Ferrite also has lower eddy current losses, so could be lower loss for those fringe fields dynamics. Thermal expansion of Ferrite rotor maybe more compatible with stator, reducing the gap. This will improve torque and lower losses.

[@flipschwipp6572]

maybe they could make the whole rotor out of ferrite material.

[@planeteuropa]

I learn much more here than from my college text books and lectures.

[@ssing7113]

You’re like that smart kid in school I didn’t listen to. But got redemption somehow to now pay attention Thank you

[@thelimitingfactor]

lol, no, I fucked off in school

[@JeffRaimer]

You rock (ha!), Jordan!

[@thelimitingfactor]

🤓 lol

[@gary_sustainableplanet]

@@thelimitingfactor Quite the tour de force building your case for ferrite being the most likely Tesla approach! One admittedly subjective factor in favor of ferrite was at Investor Day the Tesla presenter’s confidence when making the zero-rare-earth announcement. Sounded very confident the motor design is complete and scalable, even before factory is ready. Tesla’s leaders in different disciplines, to the extent we get to hear them, I give more credibility than Elon since engineers on average aren’t comfortable with the no-wiggle-room projections we heard if not already carefully worked through.

[@ricardokowalski1579]

Solid content

[@marklefler4007]

Great video. Spot on about coercivity. Note that some Aluminum and Manganese intermetallic compound can have good coercivities, so I am guessing they will eventually move to their own developed magnets, but it takes time to prove this, so I agree ferrite with a motor redesign is more likely. in the short term

[@paveln4261]

Your explanation of the possible approach of Tesla to solving "no rare earth" magnet motor is "on the money". More plausible to apply engineering than inventing new magnetic material ( which would be more exciting)

[@curtis545454]

Ferrite materials make sense. Overall efficiency will still be better than a model 3, and one day they can switch to Niron's Iron Nitride material if that scales well. Tesla already has their material engineering team busy with batteries, single castings, and spaceships. I'm sure Tesla can do better than the 93% efficiency from a random research team by utilizing their custom software. I have to imagine square magnets are not the most efficient, and custom shapes with rounded edges would do better. Absolutely nothing to back that up though.

[@thelimitingfactor]

My understanding is that you're correct on the last part. Curved magents can perform better, but more expensive. Even using different sized bar magnets increase cost. Some of the researchers made this part of their criteria (use a bar magnet of one size).

[@curtis545454]

@@thelimitingfactor Makes sense for the researchers. Depending on how the magnets are made, Tesla could make a custom shape since they are making a lot of these. A high mold cost could be justified (if a mold is the correct thing here).

[@thelimitingfactor]

Hmmmm, good point. Tesla can command that volume...

[@w0ttheh3ll]

@@thelimitingfactor If ferrite magnets are pressed into shape from a powder and sintered (I assume they are) there is no reason why simple curved or rounded shapes should be expensive at volume. Look at carbide cutting inserts, those are mass-produced in a comparable fashion.

[@patreekotime4578]

If they can manage the trick of getting Ferrite magnets to work, I dont even see why they would want/need to switch to Nitride. The Nitride likely isnt a 1:1 swap out from Ferrite, so the motors would likely have to be redesigned to accomodate them, and they would certainly cost more, even at scale.

[@diyguy446]

SOOOOOOOO GOOOOOOD as usual!!!!!!!!!

[@westcoastcarver4328]

Love it bro

[@Audio_Book_Nut]

Great vudeo Jordon.

[@thelimitingfactor]

🙏

[@WentzCraft]

Legend!

[@ericjessop292]

AC induction motors like the Air-core axial flux motor by Infinitum in Texas is another option not discussed that would fit a compact motor vehicle. Inductions motors like these use less copper and are more power dense. They are still 93% efficient and highly scalable using PCB printing techniques. It could deserve a video of its own as they have an interesting history and less known.

[@thelimitingfactor]

It does sound interesting, but Tesla said they're using magnets

[@kwon-illee6362]

There are Mn-Bi base magnets. cheap, high temperature, about half the magnet power of Nb magnets. (over 10 MGOs)

[@thelimitingfactor]

There are lots of different types of magnets. I picked the best candidates from my perspective

[@mikecawthorn7806]

Nice work bud.

[@thelimitingfactor]

🤜🤛🤠

[@budgetaudiophilelife-long5461]

JORDAN, I THOROUGHLY ENJOYED IT🤗 AND I AM IN AGREEMENT WITH YOUR THOUGHTS 👍💚💚💚

[@Patriot3]

Solid ideas

[@FamilyFirstJ]

Brilliant

[@martinkiesler]

Danke!

[@thelimitingfactor]

Bitte 😊

[@markrigoglioso]

This highly detailed video is so packed with insights I feel like I just took a class in marketing. I wonder if he was a fly-on-the-wall at more than one meeting.

[@thelimitingfactor]

🤜🤛🤠

[@ApteraEV2024]

I love Intelligent Discussion 💡

[@richardereed9205]

In the late 1980s Charles (Joe) Flynn patented the "parallel path" magnetic discovery which allowed a flux change from 0 to 4 in a magnet array using 3 magnetic fields. Two field examples illustrate the concept. S. N. N. 0. ll. ll. ll. 4 N. S. S. and S. S. N 4. ll. ll. ll. 0 N. N. S This technique has been licensed by QM Power and Boeing. QM is using it to create the most efficient HVAC motors. Since Tesla is also involved in HVAC it is possible that it too may be using this phenomenon in its motors.

[@lent6114]

Love the unique and well-researched content! You've set yourself apart (and above) most of the other Tesla themed channels. Keep up the good work!

[@thelimitingfactor]

Thanks Len 😊

[@kurtzxcvb3481]

As far as the demagnetizing of the the motor they could simply just engineer it to remagnetize itself during processes of regenerative braking or have it freewheel in a certain pattern to re-magnetize the ferrite magnets

[@flipschwipp6572]

This method would be amazing. By getting the magnetization done through the inverter and motor coils, they could even change the strength and polarity depending on the currently needed drive speed. Also they could magnetize the whole rotor packet

[@Storm3451]

If you need so much more ferrite mass in the rotor, how will it affect the rotor weight?

[@thelimitingfactor]

Alternatively, spin it at higher RPM and use the same rotor size.

[@ch4.hayabusa]

The Chevy Volt Gen 1 had crescent NdFe magnets, expensive but efficient. If Tesla can customize the shape, double the thickness, remove edges prone to demagnetization… they could build a 4-motor cybertruck cheaper than anyone else's dual motor trucks. The semi, and robotaxi could also benefit, as space isn't at a premium there. Model X is also in dire need of a complete overhaul, as Elon stated building it on top of a Model S was a mistake. A Cybertruck based Model X makes much more sense for the American/Australian/Mediterranean market.

[@martylawson1638]

My money is on Ferrite magnets too. I've seen some of the best PM-DC combat robotics motors use ferrite magnets as they offer compelling cost/power when you don't need the absolute best. Also, most motors operate at around 0.7 Tesla in the air-gap due to limitations of the iron laminations. If your rotor magnets can hit this air-gap field then you can still make a great motor even with poor magnets. This is why the high performance Ferrite magnet rotors have magnets arranged to have more surface area than the air-gap. The iron pole plates are concentrating the fields of the PM magnets.

[@thelimitingfactor]

Interesting!

[@JorgeLausell]

If they'd design so the new affordable autos are drop in swappable with highend components! Configure a supercar on the same platform. All the best pieces motor, suspension, battery. Then off the same inner castings swap in the lower performing bits and styling for the Everycar.

[@clivestainlesssteelwomble7665]

Theres a British company been building these and perfecting the control of them for years... They tend to be used in comercial vehicles ... because of their high torque and the price of large rare earth perminant motors.. They also use a minimal amount of copper.... and we need that in grid scale electrification globally. They are called AEM and used advanced switched reluctance motors ... Two other advantages are they are impervious to demagnetisation due to vibration and impacts... They are dont de magnetise if they get hot two performance limits of conventional magnets... Essentially they use field shifting opposing electro magnets. So are mostly steel and Aluminium. 😎 The breakthrough came in the control of the fields.

Good video! Still it doesn't answer the number one magnet production challenge; How to avoid magnets getting attached to the manufacturing equipment 😊

[@abelimwakijungu1226]

Is this a real problem, please educate me.

[@romteb]

Couldn't Tesla intend to use a wound-rotor synchronous motor, with no magnets, like Renault does on the new electric megane ?

[@thelimitingfactor]

They could use one of a hundred types of motors. But the video wouldn't be interesting if it were 10 hours long.

[@romteb]

@@thelimitingfactor Indeed 😄, your videos are top notch, i'd watch a 10 hours one.

[@NeilStansbury]

Another fascinating and insightful piece of analysis. An awesome piece of research thank you!

[@w0ttheh3ll]

I suspect that lower performance is also the key contributor to "75% less SIC" per drive unit. The amount of engineering benefits you get when your compact car doesn't have to beat a Porsche's acceleration is huge. Edit: I'm no expert, but I suspect you could get a lot of leeway in motor design by limiting the vehicle's top speed. The model 3 base variant's top speed is about 50% higher than it needs to be to exceed highway speed limits in most countries.

[@thelimitingfactor]

Bingo!

[@Maggio100]

75% less SiC can be achieved with 800-1000V platform, higher rpm and smaller motors. I think we will have all these three aspects in next gen motor.

[@flipadavis]

Good point. A different fixed gear ratio for the drive unit with a top speed of say 90 mph would allow for more acceleration at lower speeds with less hp.

[@rkriisk]

I agree on higher voltage being solution to drive cost down on inverter side. We already see single die sic-mosfets reaching 3.3kV level and 6.4kV in reach in next 3-4 years. I understand peoples cringe at these high voltage levels but there is nothing to be afraid of as anything above 50 v is getting dangerous unless you engineer everything properly. High voltage 1 - 3 kV would also bring motor weight down and efficiency up due to less resistive losses and copper needed.

[@Crunch_dGH]

@@flipadavisI’d say a 120MPH absolute limit (unburden) would be the most practical. Note that all Teslas are s/w limited (recent S Plaid hacked purportedly did 310MPH), so a compact capable of 120 max would be able to accommodate most wants & needs.

[@andytroo]

15:40 - could you put a nb cap on a ferrite magnet to prevent demagnetization by anchoring the field to the needed direction at the end while keeping the bulk of the magnet a cheaper material?

[@glike2]

The axial flux motors might be a key to this with their incredible advantages and use multiple magnetic chemistries for different applications.

[@alexisbono24]

One point re LFP batteries is that they are far more resilient to charge and discharge levels outside the 20%-80% range, so more practical for the majority of owners.

[@christopherleubner6633]

Another option would be to use an electromagnet with a coaxial rotary transformer. This could give a rare earth like field but it could be varied. It would also be very cheap. The coaxial transfotmer would work a lot like a wireless charger at high frequency, then get rectified with shottky doodes or mosfets. Then the current excites the rotor like that used on a car alternator. It would be smaller lighter AND more powerful than a similar RE motor.❤

[@danoberste8146]

Is there any way to remagnetize a demagnetized rotor? Perhaps during regen or recharging? 🤔

[@surferdude4487]

I suspect that the rotor would have to be dismantled to re-magnitise the permanent magnets. Depending on how they are assembled, this may not be practical. It may be cheaper to recycle the dead rotor and put in a new one.

[@jonjacoby2933]

I the spindle motor in hard disk drive can’t take advantage of higher energy product magnets due to limitation in stator laminations so ferrite could easily be used to good effect

[@duffgaryduff]

I agree with your conclusions. Teslas focus is on scale as that is the mission and mass market cars dont need 4 second acceleration cars!

[@joestafford6529]

Any thoughts on the Idra press Tesla bought for casting motor rotors?

[@thelimitingfactor]

better than hundreds of laminates

[@sergeklapwijk]

Hi Jordan, did you also look into switched reluctance motors? These are magnetless DC motors and the challenges there definitely seem to align with Tesla's focus on simulation tools.

[@thelimitingfactor]

Switched reluctance is just at type of motor, not magnet. There are a ridiculous number of motor/magnet combos.

[@philoso377]

I’d place ferrite magnet motor second to battery chemistry, such as for go the expensive lithium for sodium.

[@SpykerSpeed]

Could there be a way to re-magnetize the magnets while the car is being charged?

[@voice_from_pizza]

This reminds me of the path away from movable part hard drives to solid state storage. I can’t even deal with my old macbook’s spinning, aged hard drive anymore.

[@evkx]

New to your channel. Great content Jordan!. Did you consider that Tesla can do the same as BMW did with their latest generation motors? They have changed to WRSM motors without any magnets.

[@thelimitingfactor]

Thanks man! Overall, there are hundreds of different motor designs with and without magnets. Tesla said they'll continue to use magnets, regardless of design, so I focused on just the magnets for this video.

[@evkx]

@@thelimitingfactor aah. That explains it. I wonder if we 10 years in the future will look at 10 different solutions to one problem or everyone has consolidated to a few motor options. Volkswagen as an example promoted magnet free motors in their first electric Audi. The second was a combination of ASM and PMSM and now they ar going with only PMSM motors. Now BMW introduced brushes to solve same problem. Watching throug some of the other videos today. Again great content. Really loves the details.

[@Audio_Book_Nut]

Jordon, can you tell me where you sourced the slide on the Tesla Innovation Stack that you show in this video? Is it yours or did you get it from some other document? TIA Chris

[@thelimitingfactor]

I made it from my brain meat. That's not everything, but a quick brain dump.

[@Audio_Book_Nut]

@@thelimitingfactor Well I like the way your brain works. It has inspired me to my own homework on Tesla Innovation as there is quite a story there.

[@johnwale2886]

Thanks for this informative video. I don't think it was specifically mentioned, but ferrites tend to get weaker in low temperature conditions, which is hinted at in the slide shown at 23:27. This may or may not be a problem, but it's different behaviour to NdFeB, which gets weaker when hot. On efficiency, concentrating on the peak value can be misleading if the vehicle does not spend much of its operational time at the optimal combination of torque and speed. A drive cycle is usually more informative. It can mean that a motor with lower peak efficiency comes out more efficient on average than one with a higher peak, when you consider the usage conditions. Tesla's engineers will have considered this and it might be another factor in favour of ferrites. Also, it's unlikely but possible that Tesla are considering the use of a wound-field motor, which has no permanent magnets at all (but is differnt to an induction motor). Such a type of motor is already used by Renault.

[@thelimitingfactor]

GREAT comment thanks!

[@glenfield8027]

Great overview of permanent magnet materials. How about the possibility of a motor without permanent magnets. Switched reluctance motors are seeing greater use in HVAC systems. They can be inexpensive to manufacture and can have characteristics which make them suitable for use in an EV drive. Control is more difficult, but manageable with performance of modern embedded microcontrollers.

[@maladaptedmalarkey]

It’d be fun to be a high school physics teacher using your videos as a way to introduce, teach, and most importantly, experiment. If only teachers were paid and had access to engineers in industry with help on simulations, technologies, and materials.

[@neilmckechnie6638]

A ferrite motor together with a carbon fibre 'stamped' structural battery pack monocoque tub, with is 60% lighter than steel and alumium, may be the future of small & efficient on-road passenger transport.

[@titter3648]

Or they can just drop the magnets all together and make a pure switched reluctance motor. Or some hybrid between a switched reluctance motor and a induction motor so you get the smoothness of the induction motor for low speed and the power and efficiency of the switched reluctance motor for higher speed.

[@thom1218]

The first generation Tesla Roadster, produced from 2008 to 2012, used an AC induction motor without permanent magnets. This design choice allowed Tesla to avoid using rare-earth magnets from the start - so to believe their only option is to use ferrite magnets is a little silly.

[@thelimitingfactor]

Posting a comment without reading the pinned comment is silly.

[@thom1218]

@@thelimitingfactor Pinned comments are far too often non-sense.

[@richardkule9384]

Nice interview with Munro podcast. What kind of vehicle are you driving these days?

[@thelimitingfactor]

Tesla model 3! Only new car I've ever bought.

[@hersheykiss9500]

welcome to rare earf

[@philoso377]

When the dust has settled on Niron we can ask how sensitive is the magnetic property against extreme temperatures.

[@memrjohnno]

Wonderful piece of research. The comparison to LFP 'issues' is very important in my personal view. For a compact runabout type vehicle there is simply no need to have a level of performance such as getting up to 60 (or such) at an astonishing rate. Great video that I shall share. Thank you.