[HN Gopher] ZF makes magnet-free electric motor uniquely compact...
___________________________________________________________________
ZF makes magnet-free electric motor uniquely compact and
competitive
Author : taubek
Score : 204 points
Date : 2023-09-10 06:41 UTC (16 hours ago)
(HTM) web link (press.zf.com)
(TXT) w3m dump (press.zf.com)
| amluto wrote:
| The obvious comparison is to an AC (asynchronous) induction
| motor, which also has no magnets and couples energy into the
| rotor inductively. These are widespread. I didn't see anything on
| the website about how their design is better.
| ipbrown wrote:
| The innovation here is in the packaging, fitting the brushless
| inductive power coupling for the field excitation inside the
| shaft. T he idea of using a high frequency rotating transformer
| or inductive coupler to transmit current to the field winding
| without using brushes and slip rings has been investigated by a
| number of companies, universities, and national labs.
|
| A good survey paper of excitation systems for wound field
| synchronous machines or electrically excited synchronous machines
| is.
|
| J. K. Noland, S. Nuzzo, A. Tessarolo and E. F. Alves, "Excitation
| System Technologies for Wound-Field Synchronous Machines: Survey
| of Solutions and Evolving Trends," in IEEE Access, vol. 7, pp.
| 109699-109718, 2019, doi: 10.1109/ACCESS.2019.2933493.
|
| An example of a high frequency transformer or inductive coupling
| developed by General Motors is detailed for example in the
| following paper.
|
| C. Stancu, T. Ward, K. M. Rahman, R. Dawsey and P. Savagian,
| "Separately Excited Synchronous Motor With Rotary Transformer for
| Hybrid Vehicle Application," in IEEE Transactions on Industry
| Applications, vol. 54, no. 1, pp. 223-232, Jan.-Feb. 2018, doi:
| 10.1109/TIA.2017.2757019.
|
| Below is some work done by Oak Ridge National Lab on rotating
| high frequency transformers for field excitation.
|
| T. Raminosoa, R. H. Wiles and J. Wilkins, "Novel Rotary
| Transformer Topology With Improved Power Transfer Capability for
| High-Speed Applications," in IEEE Transactions on Industry
| Applications, vol. 56, no. 1, pp. 277-286, Jan.-Feb. 2020, doi:
| 10.1109/TIA.2019.2955050.
|
| The field excitation current is typically provided using a single
| phase high frequency transformer (20 to 100 kHz switching
| frequency) which is then rectified by a rotating full bridge
| rectifier.
|
| Just to clear up some of the misconceptions in the comments. In
| state-of-the-art electric vehicles there are basically three main
| machine topologies that are used for the main traction machine.
|
| - Interior permanent magnet synchronous machines (IPMSMs): A
| large number of OEMs and suppliers use/supply this motor
| topology, e.g., General motors, Tesla model 3, Ford, etc.
|
| - Induction machines (IMs): Also used by a large number of OEMs
| and suppliers, e.g., Tesla model S and X, G.M. for assist motors,
| etc.
|
| - Wound field synchronous machines (WFSMs) [in Europe more
| commonly known as electrically excited synchronous machines
| (EESMs) but they are the same thing] - Currently used in Renault
| and some BMW models. A large number of suppliers are developing
| them.
|
| Each of the machine topologies has tradeoffs compared to the
| others, cost, manufacturing CapEx, supply chain risk, drive cycle
| efficiency, difficulty of control, failure modes, cooling
| complexity, etc.
|
| WFSMs or EESMs have some potential advantages over IPMSMs or IMs
| for some applications.
|
| - They don't contain rare earth permanent magnets eliminating the
| supply chain and price volatility associated with them.
|
| - In terms of drive cycle efficiency generally they are more
| efficient than IMs and if the drive cycle is dominated by
| moderate torques and highspeeds they can exceed the drive cycle
| efficiencies of IPMSMs.
|
| - They are very easy to field weaken and theoretically can have
| an infinite constant power speed range.
|
| - The field excitation can be controlled to provide unity power
| factor potentially allowing the stator inverter to be downsized.
|
| The main negatives of WFSMs or EESMs compared to IPMSMs or IMs
| are:
|
| - The field excitation is more complicated and requires power
| electronics either for brushes and slip rings or inductive power
| transfer approaches.
|
| - The cooling of the field winding is difficult and typically
| spray/jet cooling of the end turns or at a minimum through shaft
| cooling.
|
| - The control of WFSMs or EESMs is considerably more complicated
| than IPMSMs or IMs.
| chris222 wrote:
| Here we have motors that don't require rare earth metals.
|
| The largest battery maker CATL is making breakthrough leaps in
| LFP batteries (which have no cobalt). [1]
|
| Recycling large EV batteries is becoming cheaper and easier. [2]
|
| Are the EV FUDsters heads exploding yet?
|
| [1] https://www.catl.com/en/news/6091.html
|
| [2] https://youtu.be/s2xrarUWVRQ?si=hBfD1lLd4dxEJI6b
| vbezhenar wrote:
| I'm not EV fudster, but for me gasoline cars are better in
| every aspect. May be except maintenance (I'm not sure, but I
| expect that I don't have to change oil every year in an
| electric car). I don't have money to buy two cars, so I need
| one versatile enough car. I can bring 100L gasoline with me to
| add 1000 km range on top of existing 500 range. I can charge it
| within 5 minutes, not 5 hours. It does not get worse with every
| year, because there's no degrading battery which costs like
| half a car. Probably the only thing that's better about EV is
| that electricity is the same everywhere, I can't charge it with
| bad electricity mixed with water in the old station, LoL.
|
| Electric cars probably are the future, but I don't like this
| future. They don't have a soul.
| rootusrootus wrote:
| Those are all pretty tired arguments, and already debunked
| thoroughly. I spend a lot less time refueling my EV than I
| ever did on my ICEVs. And it doesn't take me any longer for a
| road trip stop than it did before, I always took 15-20
| minutes to take a leak and stretch. Almost nobody does a 5
| minute in-and-out on a road trip. You might, but you also
| carry 100L of gasoline with you, which is _very_ uncommon.
| And as someone who 's owned vehicles with gas tanks in the
| passenger compartment, I strongly recommend against it.
|
| > Electric cars probably are the future, but I don't like
| this future. They don't have a soul.
|
| Now you're being honest. You don't like them because they're
| too quiet. That is a valid opinion.
|
| > I'm not EV fudster
|
| Yes you are ;-).
| olddustytrail wrote:
| The SSL cert on your website is probably expired (cloudflare
| is warning about it). I suggest you just use letsencrypt and
| auto renew with certbot, or whatever they use these days.
| vbezhenar wrote:
| Thanks, that's weird because my website is basically github
| pages. I think I got it fixed, not in the very best way,
| but it kind of works.
| KennyBlanken wrote:
| > Electric cars probably are the future, but I don't like
| this future. They don't have a soul.
|
| The idea of a transportation machine having a "soul" is
| ridiculous.
| myself248 wrote:
| Nah, when you've spent ten thousand hours doing something,
| you get a feel for it. It's not a sentient being, but it
| gains a feeling and a significance beyond what's printed on
| the window sticker. (I would argue that sentient beings
| don't have souls either. It's just a shorthand for a
| poorly-defined set of attributes and behaviors.)
|
| A lot of people anthropomorphize machines, as it helps
| engage our built-in anticipation instincts to track when
| the machine will be "hungry" or "tired" without expending
| conscious thought. If the machine starts to sound or feel
| different, even in ways we can't put into words, that may
| surface as a sense of "attitude" or "unhappiness", and it
| may do so long before the difference would be dramatic
| enough to merit other mention. On-board diagnostics are
| great at identifying certain malfunctions in the engine and
| a few other systems, but driveline and suspension are still
| largely unmonitored except by ear, by feel, and by
| intuition. And there are still plenty of engine conditions
| that manifest as a gut feeling long before they set a DTC.
| Getting something checked out when it feels "off", versus
| waiting until it fails more obviously, may avert an
| unscheduled mishap in the middle of a cross-country
| roadtrip.
|
| There are certainly lots of people who haven't spent that
| much time behind the wheel, or whose coming-of-age wasn't
| inextricably linked to the jingle of keys as a symbol of
| freedom and independence, or whose appreciation of rock and
| roll doesn't equate the growl of an electric guitar with
| the growl of an engine. Those people are to be forgiven for
| not seeing cars as having souls, but that lack of
| imagination on their part should not limit the
| imaginations, or the useful instincts, of the rest of us.
|
| EVs have their own quirks and feelings, but there's not
| such a complicated web of air and temperature and chemistry
| and hydraulics and cable-stretch and dozens of individual
| bearings and mounts and linkages behind their behaviors.
| And they don't have a century of hot-rodding culture built
| up around them yet, no flames painted on the side, nor any
| combustion to inspire same. No exhaust notes to tune; if an
| EV's noises show up in music, it'll be more like Aphex Twin
| than Van Halen. Which is all well and good, but all of
| these things move EVs farther from any of the behaviors
| that we refer to with the shorthand of "soul".
| thsksbd wrote:
| Some folks are excellent drivers.
|
| I find the ability to understand the concept of a car's
| "soul" to a very reliable way to separate them out.
|
| Why? Because "soul" doesn't mean the immortal soul endowed
| by our Creator. It refers to the feel and responsiveness of
| a car. The car's personality, if you will. It refers to
| every unique behavioral trait that the car has acquired
| through its design and life been driven.
|
| On my old truck the clutch would feel different after my
| wife drove it. It took a few miles to get the feel back. It
| drove better with a couple hundred lb on the bed. On my '13
| golf I can feel a slight "give" on the steering from wear.
| I can feel the car and drive it through a corner with the
| wheels slightly squealing [1]. Thats the edge grip. On the
| KIA I can feel the difference in the engine and
| transmission (especially) behavior before and after the oil
| has warmed up. On the Golf, the shifter is "lazy" until she
| warms up.
|
| Within 10 miles of getting a new set of tires I know if I
| hate them or love them. I get a feel for their limits.
|
| I hate renting cars. Despite the low millage, they feel
| worn and lose. I also feel like a fish out of the water in
| a car that is not mine.
|
| As you add mechanical/electrical complexity these various
| feedbacks from the car are washed away. Professional
| drivers hate these aids. This is widely known in the
| aviation industry and many planes add artificial feel to
| give pilots feedback on the fly-by-wire systems.
|
| So ya, a good driver feels as if his car has a "soul" just
| like a good pilot can feel his plane's "soul". There's no
| immortal soul in a car, no consciousness, but there is a
| whole lotta love.
|
| [1] obviously on track days
| svnt wrote:
| It sounds like your assessment of the complexity of a
| vehicle is specifically tuned to mechanical features of
| cheap gasoline cars. I would suggest it might be more
| accurate to describe this as personality instead of soul.
|
| Unsurprisingly electric vehicles, which do not have
| clutches or transmissions at all, or temperamental
| engines with inconsistent power curves, will exhibit
| little signal in the areas you have tuned yourself to
| perceive. This does not indicate anything about them in a
| universal way.
|
| Your response indicates that you are perhaps incurious
| about the nuances of driving an EV. Since it sounds like
| you have invested a lot in sensing personality specifics
| of gasoline vehicles, this makes sense.
|
| Perhaps early EV attempts were muted in their expression
| of activity personality. Entry level Teslas certainly are
| not fun to drive in the same way as an old Golf. Have you
| tried the Ioniq 5?
| mlyle wrote:
| > I can bring 100L gasoline with me to add 1000 km range on
| top of existing 500 range
|
| This is the big advantage.
|
| > not 5 hours
|
| This one is mixed. You can charge the EV at home for ordinary
| use. That's better.
|
| For road trips, you can use DC fast charging to add a bunch
| of range in 30 minutes. This is worse, requiring combining
| charging and meal stops.
|
| PHEVs are a decent compromise, though: you can do basically
| all of your driving electrically, and then burn a little bit
| of gas on road trips.
|
| > It does not get worse with every year
|
| Sure gasoline vehicles become more maintenance heavy and
| terrible over time. EV degradation is probably around 10-15%
| range lost after 5 years typical today.
|
| > May be except maintenance
|
| Odds are you don't deal with brake pads anymore, and yes, no
| oil changes. The sheer torque of most models feels like a
| spaceship when you press down the gas pedal.
| KennyBlanken wrote:
| 18 minutes to 80% charge in the 800v cars.
|
| Furthermore: for all the whining people do about "sitting
| around waiting for it to charge", those people conveniently
| leave out all the time they spend driving to/from and
| waiting at a gas station...whereas many EV owners just get
| home and take about 30 seconds to plug in.
|
| So, for the tradeoff of having to wait ~20 minutes instead
| of 5 to fuel up on a long trip, you get to not spend ~5
| minutes every week or two driving to a gas station and
| filling up.
|
| Most Americans don't even drive enough per day to make it
| _necessary_ to have level 2 in-home charging.
| jamiek88 wrote:
| And it works well too. My Kia ev6 goes from 20 to 80
| percent in 18mins.
|
| Leaving home on full charge gets me around 280 miles on
| freeway (Circa 310 just pootling round town ev's are
| opposite to ice like that).
|
| It's better to drive at normal 75mph ish freeway speed
| and just fast charge rather than worrying about range and
| 'hyper miling'.
|
| The 800v system is great real world.
|
| We are on west coast and charging infra is decent though
| even non Tesla.
| hwillis wrote:
| >> I can bring 100L gasoline with me to add 1000 km range
| on top of existing 500 range > This is the big advantage.
|
| No, absolutely not. Who brings 160 lbs of gasoline with
| them anywhere? That's twice as much as an average cars gas
| tank. How many people do you know that have ever brought
| any gas on any trip ever?
|
| The "advantage" of being able to drive 12+ hours without
| taking a couple hours to charge is absolutely ridiculous.
| It's not something people do or should do. The only
| reasonable circumstance is if you're on a camping trip or
| something, and somehow driving hundreds of miles without
| passing a source of electricity- in which case yes, use a
| gas/ethanol car.
|
| In my honest opinion, it's a ridiculous demand that you
| should be able to drive 800 km without taking more than 5
| minutes to stop. It's minimum 6 hours of driving, and like
| 30-40 minutes of charging. It's petulant to complain about
| that like it's a real issue.
|
| The real advantage is cost. It costs a _lot_ of money to
| get a large battery that can charge quickly, when a $20k
| Civic can do it. Smaller the EV, the slower the charge, and
| the more inconvenient it is.
| myself248 wrote:
| It's not necessarily at one stretch, it could also be for
| several days camping away from services.
|
| One of the places I've long wanted to go is about 100
| miles from the nearest town with a gas station, but the
| roads are particularly rough so I don't expect to get
| highway mileage or anything close to it. In my past off-
| roading I've gotten roughly half my highway mileage, so
| let's say it costs 200 "miles worth of gas" to get there.
|
| If it takes 200 miles to get in, it also takes 200 miles
| to get back out, plus some margin for error, plus
| whatever I burn while I'm there. A few days of cooking
| and stuff can burn a few gallons, more if I'm also
| running the fridge, which is really nice on a long trip.
| Add that I might want to visit a few sites over a few
| days, and I could easily see needing more than my
| existing 500-miles-in-ideal-conditions range.
|
| It's trivial for me to carry another 10 gallons, which
| doubles my highway range to 1000 miles, and that's with
| one of the most fuel-efficient hatchbacks on the road. A
| larger vehicle would need quite a bit more.
|
| I simply don't know a way to do that with an EV.
|
| Now admittedly that's a contrived example, but it's a
| just-slightly-more-extreme version of some real trips I
| take from time to time, and it's a trip I do honestly
| plan to take one of these days.
| hwillis wrote:
| couldn't even read to the second paragraph?
| jcgrillo wrote:
| I think they mean this part:
|
| > The only reasonable circumstance is if you're on a
| camping trip or something, and somehow driving hundreds
| of miles without passing a source of electricity- in
| which case yes, use a gas/ethanol car.
|
| But is it, actually, the only reasonable circumstance?
| That's an exceptionally strong claim.
| jcgrillo wrote:
| > The "advantage" of being able to drive 12+ hours
| without taking a couple hours to charge is absolutely
| ridiculous. It's not something people do or should do.
|
| I pretty regularly drive between Washington, D.C. and
| northern New Hampshire. That's about a 9hr drive under
| good traffic and weather conditions, 575mi. My truck gets
| about 13.5mpg and has a range of around 300mi, so I have
| to stop for fuel once. It's nice to get out of the car
| every 4hr or so anyway. If I was driving, say, a Rivian
| that gets ~400mi/charge I would also only have to stop
| once, but the stop would take about an hour and a quarter
| [1]. I could probably live with that, and I'd appreciate
| not burning as much dino juice.
|
| However, I recently did that trip with the truck totally
| freighted, towing a two axle trailer. I got 9.5mpg, which
| is about 65% what I get empty, putting my range at
| ~200mi/tank. I had to fill up twice. A Rivian under
| similar conditions will be getting about 260mi/charge.
| That means I'd have to charge twice, adding 2.5hr to
| what's already a 9+hr trip.
|
| Another thing my truck can do is go off road. It has a
| mild suspension lift, and locking differentials front,
| center, and rear. It runs slightly taller than stock
| tires to give it more ground clearance. I can roll over
| 2-3ft high rocks without having to think too hard about
| it. Under these conditions, I expect to get even worse
| than 65% of my empty highway mileage. 50% is common, and
| it can even be as bad as 35% in really technical terrain.
| Ignoring the fact that the Rivian would likely break if I
| tried to take it places my truck can go off road that
| translates to something like 150-200mi/charge. And if
| you're actually taking it off road you better plan for
| plenty of reserve, because there aren't any chargers
| there.
|
| > Who brings 160 lbs of gasoline with them anywhere?
|
| Someone who wants to get there, most likely. If you
| calculate you need to make it a certain distance, and you
| know your expected fuel burn rate, then you can count up
| the number of jerry cans you need. In this case they
| needed 5 of them.
|
| So it's a question of capability, right? My truck is in
| some ways more capable than the EV alternative. One
| capability I have is to be able to throw some cans in the
| back and extend my range. Another capability I have is
| being able to travel long distances under adverse
| conditions.
|
| Crucially, though, the capability my truck has that the
| competition lacks is I can fix it and maintain it without
| having to hire a specialist. It has simple, impeccably
| engineered field serviceable systems.
|
| And it cost 1/6 what a Rivian would.
|
| If someone makes an EV with these capabilities, I'll buy
| it, even if it does cost as much as a damn house. Until
| then, I'll stick with my old truck.
|
| [1] https://www.caranddriver.com/news/a38944499/2022-rivi
| an-r1t-...
| toast0 wrote:
| > The "advantage" of being able to drive 12+ hours
| without taking a couple hours to charge is absolutely
| ridiculous. It's not something people do or should do.
|
| One person shouldn't drive 12 hours, but it's not bad for
| two people to split. It's not unreasonable at all if you
| have three drivers.
|
| Yes, you'll probably stop somewhere to eat and use the
| restroom. If that somewhere happens to have decent food,
| and a fast charger, and the fast charger doesn't have a
| line longer than your mealtime, then an EV would probaly
| work out. If those stars don't align, your long day of
| driving got even longer.
|
| I don't bring gas cans on long trips, because gas
| stations are ubiquitous; but I have enough gas equipmemt
| at home that I keep them at home, and I use them to fill
| up my cars at home regularly to keep the gas fresh, and
| avoid paying the markup of my nearest gas stations.
|
| PHEV is a better choice than either IMHO. You get two
| year maintenance windows, you get long distances between
| fueling, you can use electric for local trips if it makes
| sense, you can live in an apartment with no charging
| infrastructure, you get reduced brake wear, you get a lot
| of low end torque if that's relevant to you. You probably
| lose out on cargo space though, cause PHEVs tend not to
| have handy places to stash the batteries. Oh, and
| internet people will argue that it's the worst of both,
| and you'll have to ignore them.
| qingcharles wrote:
| Exactly! See my comment here:
|
| https://news.ycombinator.com/item?id=37457646
| hwillis wrote:
| > I'm not sure, but I expect that I don't have to change oil
| every year in an electric car
|
| The only critical replacement is brake calipers and fluids: h
| ttps://www.tesla.com/ownersmanual/modelx/en_eu/GUID-E95DAAD..
| .
|
| Brakes tend to last much longer because the car uses the
| motor to brake. Some Tesla motors are oil-cooled, some are
| just air cooled and the reducer just uses grease[1] instead
| of oil. There are no piston rings, no blow-by, no sliding
| friction, no wear items, the temperature stays below 100 C,
| the pressure is always ambient, and the case is completely
| watertight. The oil/grease can last practically forever.
|
| > I can bring 100L gasoline with me to add 1000 km range on
| top of existing 500 range.
|
| Driving 12 hours at a time is unsafe and you should not do
| it. If you are regularly driving 1500 km into wasteland, an
| electric car is not for you. If you only do it a few times a
| year, I recommend renting.
|
| > I can charge it within 5 minutes, not 5 hours.
|
| Have you not heard? They can charge 200 miles in 15 minutes.
|
| > It does not get worse with every year
|
| It's a _car_. They _absolutely_ get worse every year. Driving
| at high speed over bad roads takes a toll and all cars fall
| apart over time.
|
| > Electric cars probably are the future, but I don't like
| this future. They don't have a soul.
|
| Did televisions, before flatscreens replaced them? I don't
| think so. I think it was just the nostalgia for a time when
| it was new and important. But a car now is a conveyance.
| 99.99% cars have as much soul as an elevator- another thing
| that used to be special and personal.
|
| If you want soul in the thing you drive to work, you always
| had to buy something special. You did not find it in a Honda
| Civic. If you want that, buy a motorcycle, or an E100 car.
| Those things will still exist even if EVs completely replace
| gasoline, because they just aren't the same thing.
|
| You are not afraid of electric cars replacing racecars, or
| grand tours through the mountains or deserts or forest. You
| are sad about electric cars replacing 8 lanes of LA traffic,
| of I-98 being _quiet_ , of less children with asthma. That's
| a silly thing to be sad about. The soul of driving is not
| going anywhere.
|
| [1]: Because I NEVER tire of saying it: grease is amazing. It
| seems inefficient because it's thick like peanut butter, but
| it's the best. It's shear-thinning, so that as soon as it
| starts moving, it spreads into an incredibly thin low-
| viscosity layer that's just as frictionless as oil. Unlike
| oil, it never drips off, never needs pressure, always covers
| the surface. Contamination works itself out automatically
| (unlike in oil, where it's recirculated). It's chemically and
| thermally stable. Grease is the BEST.
| screwturner68 wrote:
| I live in a large city, I drive a small car and I only drive
| about 3000 miles per year. Right now gas is ~$5.35/g at the
| station down the street and it's ~0.18/KW. It takes 114KW to
| "fill" a Tesla S, so ~$20.50. The range on a Tesla S is 405
| miles, so ~19.75 miles /dollar. My VW gets ~30MPG or ~5.6
| miles/dollar. The numbers make sense as does the range, I
| don't know many people who drive over 400 miles per day ever.
| The issue as I see it is quality and price, Tesla is sub-Kia
| quality at BMW prices. Honestly I think a lot of people are
| just looking for an excuse not to move to an EV, just like
| they did with going to unleaded gas or using LED bulbs.
| Everything is going electric and people that can't see that
| are just willfully blind -the Saudis knew this years ago, I'm
| not sure why so many people think it's a surprise.
|
| As far as soul, what is stopping auto makers from making cool
| looking cars, honestly I don't know. One of the things I
| thought was cool about the Tesla 1 was that it was a good
| looking convertible and not something that looked like a
| rolling doorstop (Prius). Maybe EV will usher in a new
| generation of car makers that will make good looking cars
| again, we can hope.
| nullc wrote:
| > Tesla is sub-Kia quality at BMW prices.
|
| Indeed. Plus locked down maintenance (using DRM to prevent
| you from fixing your own car), and constant invasive spying
| (including video from the cars cameras
| https://www.reuters.com/technology/tesla-workers-shared-
| sens... ).
|
| > not something that looked like a rolling doorstop (Prius)
|
| Cars are shaped the way they are today for aerodynamic
| reasons.
|
| > I live in a large city, I drive a small car and I only
| drive about 3000 miles per year.
|
| Hopefully you can see that what works for you doesn't work
| for everyone.
|
| Living in a city and only driving 3000 miles a year... Have
| you considered not owning a car at all? :)
|
| Given your figures, at 3000 miles per year it would take
| 108 years for the improved fuel economy of the Tesla S to
| pay for its added cost over a Kia with comparable build
| quality.
|
| This is part of the reason you don't see the improved
| $/mile being so heavily advocated for EV's especially high
| end ones: The improvement isn't enough to pay for the added
| cost, unless you're a very heavy user and heavy users have
| more range, recharging locations, and recharging time
| concerns.
| nomel wrote:
| A significant difference is that I can get around that
| range for a few grand, with an ICE. It's disingenuous to
| omit initial battery/costs of ownership from these
| calculations. $/mile the actual metric (and that's even
| difficult with the road tax evasion that EVs currently
| enjoy).
|
| I own an EV, and love it, but I also suspect it's going
| right to the dump after the battery gives out.
| qingcharles wrote:
| If you carry 100L of petrol around in your car you must admit
| you are a very niche segment.
|
| I've driven in dozens of countries, sometimes very far from
| fuel stops, but I've never once had the need to carry any
| additional fuel inside my vehicle. I think the furthest I can
| ever remember being from a petrol station is about 120 miles.
| davewritescode wrote:
| There's no doubt in my mind that EVs are the future, it's just
| hard to fault people who don't want to pay more for an
| objectively worse overall product.
|
| For the record, I think within the next 10 years that will
| change but I don't think 5 ton EV trucks are the answer.
| starkparker wrote:
| I mean, the first combustion-engine cars had the same market
| reaction. A recollection of the late 19th century and early
| 20th, from 1930:
| https://www.saturdayeveningpost.com/2017/01/get-horse-
| americ...
|
| The whole story has salient parallels -- parts suppliers were
| either reticent or inexperienced, fuel was cheap but not
| widely available, motors were slow, investors put money in
| before the market was there, founders lamenting the state of
| the modern laborer, early adopters stuck needing parts for
| vehicles orphaned by suddenly defunct manufacturers, and the
| guy getting all the money and attention is a wealthy idiot
| making self-crashing death traps who relies on free advice
| from his witless fans to avoid failure and profit. There's
| even a cameo from early EV manufacturer Electric Vehicle
| Company in 1899.
|
| Tangentially, this is evocative:
|
| > In the uncertainty of what the public would want, a great
| many strange contraptions were put together. Joseph
| Barsaleaux, a blacksmith of Sandy Hill, New York, built a
| motor horse. In his device, the horse moved on a single wheel
| about two feet in diameter, with the wheel attached to the
| shafts just as was a live horse. Reins attached to the mouth
| of the horse served as a steering gear, because the machinery
| was inside the horse and had to be regulated some way. The
| contraption weighed about 550 pounds, had a cruising speed of
| six miles an hour, and attracted some serious attention.
|
| EV makers should probably stop trying to make mechanical
| horses -- EV motors and cars that aren't competitive with ICE
| equivalents -- and find a form factor that better suits both
| the market _and_ the current state of the technology. Class 2
| ebikes and small carts feel closer to that answer on short
| runs, but the long-haul equivalents are still missing.
|
| Hell, Winton in this story is a bicycle manufacturer who
| makes his first horseless carriage from bicycles.
| somerandomqaguy wrote:
| That doesn't disagree with what he's saying though; it's
| still in a transition phase. Range loss issues from cold
| weather and/or towing are still a concern, inability to
| charge at home is a concern, large upfront costs are still
| a concern, the weirdness of fast charging stations is still
| a concern. They're solvable issues and in time will be, but
| they're issues lot of people don't want to deal with while
| things are still in flux and don't see enough value in
| paying the cost of being an early adopter.
| jcgrillo wrote:
| I don't _disagree_ , but there's one major difference at
| play here. Those early horseless carriages--and maybe even
| the first ~9 decades of automobiles--were objectively
| simple, maintainable, rebuildable machines. Many examples
| from that early era are still running. None of them had
| proprietary computer systems, delicate plastic parts, etc.
|
| I think it's substantially less likely that there will be
| any vehicles from the first couple decades of this century
| running 100 years from now. And it's an important part of
| sustainability, cost of ownership, etc.
|
| It's hard to see the point in owning a vehicle from this
| century unless manufacturers start building them to be
| _good transportation tools_ instead of what they appear to
| have become--a means to sell a financial instrument (a car
| loan), an ads serving platform, and a data collection
| mechanism. For me personally that is really the biggest
| barrier to owning an EV.
| hinkley wrote:
| We had a friend end up with an ev rental they didn't ask for
| ans holy shit did that ruin her weekend. Technology
| Connections has been talking about it recently. Tesla is
| winning as a power delivery standard mostly because third
| party charging networks are such a giant clusterfuck.
| userbinator wrote:
| Let me guess, she forgot to charge it or wasn't aware of
| how long it takes?
| hinkley wrote:
| She couldn't find a charger that would charge in under
| six hours. She was only here for 3 days. 12 hours of
| charging is most of your waking hours.
|
| She plugged it into my house the first night. We realized
| the next morning it wouldn't hit 100% until after she was
| due to return the vehicle. She picked up the car at the
| next airport over and drove the scenic route to our
| house. All of the chargers on that route were adding
| miles slower than 1 per minute, which means one hour of
| charging per hour of driving. She barely got here before
| sunset.
| rootusrootus wrote:
| > objectively worse overall product
|
| ... except the EV is objectively better, not worse.
|
| Literally the only thing an ICEV can claim superiority on is
| refueling time. And even that comes with big caveats: it only
| applies to road trips, and even then it's unrealistic. Around
| town, refueling an EV takes essentially zero time, far less
| than an ICEV. On a road trip, the ICEV does refuel faster,
| but in real life road trip stops are typically 15-20 minutes
| anyway, and that's enough to refuel a modern EV.
|
| What's exciting is that while EVs are already objectively
| better, the underlying technology is still evolving quickly
| and the future is very bright. We're already able to do
| things with EVs that aren't even possible with an ICEV, and
| this is just the beginning.
| nomel wrote:
| Now, go live in a cold climate for a while, a little
| outside of a city.
|
| There's no single dimension of experience to rate these
| things on. I know several people who want an EV, but have
| been, fairly, dissuaded by their EV owning neighbors,
| especially when "per dollar" comes into play.
| slow_typist wrote:
| Nice job, now magnet free generators for windmills please.
| mannykannot wrote:
| The same technology should work for them, I believe.
| slow_typist wrote:
| Sure; the economic case might be trickier though.
| mannykannot wrote:
| The mismatch between a constrained rare earth supply and
| rising demand for motors and generators means that the case
| gets better as time passes.
| samtho wrote:
| This is not new, if you have a car with any fossil fuel motor,
| you likely already have a similar device: your alternator. By
| applying a voltage between 2 and 13 to the exciter coil, you can
| adjust how much is drawn from the primary winding.
| stephen_g wrote:
| A car alternator uses brushes or slip rings to get power to the
| excitation coils, which is a big part of what the motor in the
| article has been designed _not_ to use.
| userbinator wrote:
| There are brushless car alternators.
|
| https://www.delcoremy.com/alternators/find-by-model-
| family/3...
| rootusrootus wrote:
| It still boggles my mind how much power a modern electric motor
| gets from such a small package. I'm so used to big engines
| weighing hundreds of pounds making maybe a couple hundred
| horsepower. Now we have electric motors making quite a lot more
| (and not to mention insane torque) that I could easily pick up
| with my hands.
| hinkley wrote:
| There are motors with peak efficiency about 90%. The first one
| of those I ran into was fifteen years ago. Which means not only
| is it possible but the patents will have expired, if not now
| then soon.
|
| Power density has gone almost too far. There's one pancake
| motor I've seen recently where the shape of the enclosure is
| dictated by mounting concerns. You have to be able to mount the
| motor to something it can't tear apart. If they shrunk that
| motor another 20% then it would be half housing. I'm not sure
| where you go from there. Thinner? Motor per wheel?
| travisporter wrote:
| Motor per wheel sounds interesting. As I understand it's not
| ideal for handling because of unsprung weight. Maybe that
| will change? Would be very excited about the prospect of
| converting cars to purv (somehow)
| nomel wrote:
| Motor per wheel doesn't have to be in the wheel. Could be
| through a very compact axle, maybe with a fixed gear box to
| get the angle right.
| hamburglar wrote:
| What would be wild (and probably wildly impractical) is
| an inductive coupling between the motor (inboard,
| unsprung) and the wheel.
| FirmwareBurner wrote:
| Well, magnet-less separately exacted synchronous motors with the
| exact same architecture have existed since ... _checks notes_ ...
| over 100 years, so it took me a while to digest the whole
| marketing fluff where they use an entire page to explain how an
| electric motor works, and see what 's so special about this
| besides the claim that it's now "up to 90mm more compact
| axially".
|
| It seems like the big innovation here is that it doesn't use slip
| rings and brushes anymore, and the power to the rotor is now
| transferred via induction coils:
|
| _" energy is transferred inductively, i.e. without mechanical
| contact, into the rotor, generating a magnetic field by means of
| coils. Thus, the I2SM does not require any brush elements or slip
| rings. Furthermore, there is no longer any need to keep this area
| dry by means of seals. As with permanently magnetized synchronous
| motor, the rotor is efficiently cooled by circulating oil."_
|
| The good part is there's no more brushes to wear out and no dry
| seal needed so the motor can now be oil cooled from the inside as
| well, but to me it raises the big question about the power losses
| incurred by the energy that's transferred to the rotor via
| induction versus the previous direct contact via brushes and slip
| rings.
|
| Those coils seem to be quite far apart from one another, have a
| look at this moment in their video:
| https://press.zf.com/press/en/media/media_60352.html?kaltura...
| [deleted]
| baybal2 wrote:
| > The good part is there's no more brushes to wear out and no
| dry seal needed so the motor can now be oil cooled from the
| inside as well, but to me it raises the big question about the
| power losses incurred by the energy that's transferred to the
| rotor via induction versus the previous direct contact via
| brushes and slip rings.
|
| Slip ringed motors can be perfectly oil cooler as well. And you
| will need oil seals and drains in under any circumstances you
| use oil cooling.
| twobitshifter wrote:
| Brushes and slip rings seem like they would be more efficient,
| but they are adding friction and sparking that isn't part of
| this, and as they wear become less efficient. BLDC showed that
| induction wins through one conversion, but this is making 2.
|
| Simple napkin math: If you compare BLDC to Brushed efficiency.
| Best BLDC is 90% efficiency and best brushed is 80%. Even if
| the inductive rotor loses as much energy as the complete BLDC
| motor, it would still perform on par with a brushed motor.
| TaylorAlexander wrote:
| Well, BLDC doesn't really use induction at all. It just makes
| a magnetic field that pushes on magnets.
| [deleted]
| TaylorAlexander wrote:
| I don't understand why this is being downvoted? Is this a
| terminology thing? I design my own brushless motor
| controllers. A brushless motor operates by generating a
| magnetic field in fixed coils and using that magnetic field
| to directly act on magnets.
|
| Wikipedia defines magnetic induction thusly:
| "Electromagnetic or magnetic induction is the production of
| an electromotive force (emf) across an electrical conductor
| in a changing magnetic field."
|
| So basically using a changing magnetic field to create
| voltage in a conductor. While it is true that induction
| occurs in a brushless motor as a secondary effect (the
| rotating rotor induces back EMF on the stator coils), the
| primary mechanism of movement is a magnetic field
| physically acting on permanent magnets - no induction
| involved.
|
| This is distinct from an AC induction motor, about which
| Wikipedia says: "An induction motor or asynchronous motor
| is an AC electric motor in which the electric current in
| the rotor needed to produce torque is obtained by
| electromagnetic induction from the magnetic field of the
| stator winding."
|
| Basically in an induction motor, induction is a required
| effect for the operation of the motor, rather than a side
| effect as in a brushless motor.
|
| So while induction occurs in a brushless motor, if
| induction could be magically disabled the motor would still
| work. This is not true for an induction motor.
| rand0mx1 wrote:
| There will be large losses due to induction method.
| WJW wrote:
| "large" is meaningless unless you can compare it to the
| friction cost of the brushes they replace.
| ilyt wrote:
| Except you're competing with brushless motors using
| magnets, not other induction motors.
| Farmadupe wrote:
| Out of interest, what could make such a design better than a
| traditional inductive motor? Such motors already suffer
| inductive losses, and do not need slip rings or brushes, and
| presumably do not an additional set of windings to transfer
| power to excite the stator?
|
| Just could the two sets of coils be optimized for their own
| purposes?
| formerly_proven wrote:
| Inductive coupling in an ASM is at the drive frequency
| (hundreds of Hz), inductive coupling in an inductive
| electrically excited SM can work at an arbitrary frequency,
| e.g. 100 kHz. You can also see in the ZF release how small
| the coils for transferring the excitation current are
| compared to the main windings, they are the small rings on
| the left side.
| FirmwareBurner wrote:
| _> what could make such a design better than a traditional
| inductive motor_
|
| Traditional induction motors, compared to these with wound
| rotors, are heavier and bigger in size for the same power
| output, and have less efficiency especially at starting/low-
| speeds.
| sidewndr46 wrote:
| that is only true if you don't have a VFD. At that point
| you can basically get whatever you want out of them until
| they melt or blow out a bearing
| Loughla wrote:
| So then it comes down to cost? If this is cheaper than a
| motor and vfd, then it's still a win?
|
| Source: the one time I restored a massive JT Towsley
| jointer and had to get a vfd for the giant motor I had to
| put on it. In other words, I have no idea what I'm really
| talking about.
| sidewndr46 wrote:
| as others commented, this is not new tech. It's the
| result of the PR department needing to make a press
| release.
| franciscop wrote:
| Oh I was just going to comment that those looked like some sort
| of brushes and thus that would negate other advantages, but
| after reading your comment and carefully reading the notice
| yeah that is definitely great! Induction coils instead of
| brushes for the rotor current def seems like a key
| advantage/development.
| userbinator wrote:
| Brushless synchronous induction motors have also existed for a
| _long_ time.
| FirmwareBurner wrote:
| Yes, but these ones with externally excited wound rotors have
| the advantage of more torque and efficiency at compact
| packages but have had the disadvantage of brushes that would
| wear out, create carbon dust and electrical noise.
| fluxeb wrote:
| It's more than that.
|
| A great write-up by Tesla (2007) [1] In an
| ideal brushless drive, the strength of the magnetic field
| produced by the permanent magnets would be adjustable. When
| maximum torque is required, especially at low speeds, the
| magnetic field strength (B) should be maximum - so that
| inverter and motor currents are maintained at their lowest
| possible values. This minimizes the I2 R (current2 resistance)
| losses and thereby optimizes efficiency. Likewise, when torque
| levels are low, the B field should be reduced such that eddy
| and hysteresis losses due to B are also reduced. Ideally, B
| should be adjusted such that the sum of the eddy, hysteresis,
| and I2 losses is minimized. Unfortunately, there is no easy way
| of changing B with permanent magnets.
|
| Essentially, this new tech combines the best of Permanent
| Magnet Brushless DC and Induction motors. It allows you to
| change the magnetic field B without contact.
|
| The losses in the shaft coils are low when B is low so the
| gains in efficiency for an "eco mode" would be excellent as you
| modulate B for low torque and you would still retain the
| ability to crank up the power in a "sport mode" at the cost of
| efficiency.
|
| [1]https://www.tesla.com/blog/induction-versus-dc-brushless-
| mot...
| sitkack wrote:
| Exactly. The B field can be cranked up for short a duration
| to maximize torque. The rotor could also have much lower
| inertia.
|
| I sketched out this same topology, with inductively coupled
| coils for the rotor's magnetic field. If you don't need the
| fields to reverse (they wouldn't with a magnetic field). Then
| you could still have small PMs in the rotor with a coil to
| provide boost field for additional torque during
| acceleration.
| belter wrote:
| To be fair, is practically on one of the first lines of the
| press release: "...In contrast to the magnet-free concepts of
| so-called separately excited synchronous motors (SESM) already
| available today..."
| franciscop wrote:
| That's the normal/traditional advantage of "brushed" motors
| vs synchronous motors, but the brushed motors have the
| massive disadvantage of having a mechanical contact (the
| brushes) that wear off, need to be sealed, etc. The advantage
| here is that it behaves like a brushed motor, but without the
| brushes!
| londons_explore wrote:
| The animation seems to show that the rotor has a DC (ie.
| constant) field. That is easy to do with slip-rings and a DC
| current source, but with any induction mechanism, there must be
| a rectification stage on the rotor. They don't show any of
| that.
| Animats wrote:
| Hm. Do they have diodes in the rotor?
|
| It's common for large, power station sized, generators to
| have that. The field windings are on the rotor, and the heavy
| power comes out from the stationary armature windings. To
| power the field windings, there's a smaller generator as part
| of the machine, but it's the other way round - stationary
| field, rotating armature producing power. The output of the
| smaller generator is rectified by diodes on the rotor to
| provide DC power for the main rotating field. No commutators
| or slip rings. No wear, no arcing.
|
| Did someone just scale this down for motors?
| MayeulC wrote:
| I'm wondering if performance could be improved by controlling
| the polarity of the rotor coil fields, to push against the
| stator-induced ones. Since some semiconductor rectifiers are
| necessary in the stator, it doesn't sound much more complex
| to control the polarity. Part of the control logic could be
| handled before the inductive power transfer mechanism, by
| modulating the frequency, though it gets complex as you
| probably want to tune the resonant frequencies of the sender
| and receiver.
| Animats wrote:
| Wind turbines work that way. Early wind turbines had to
| mechanically rotate at a fixed speed to match the grid.
| With modern ones, the field is sometimes electrically
| rotated to adjust for rotor RPM. This can be done quickly
| as the wind changes. The range of control is not large,
| though. This is a quick adjustment made electronically
| until the blade pitch can slowly be changed by motors to
| re-tune the wind turbine for the current wind speed. Look
| up "doubly fed induction generator".
| qwertox wrote:
| So it's the `I2` from the `I2SM`-name which is the key part,
| referring to the induction of current into the outer coils, and
| then the magnetic induction to create the forces.
| userbinator wrote:
| It's just an inductively excited synchronous motor; this is a
| decades-old design being brought out again to satisfy the current
| trending buzzwords in the industry.
|
| https://patents.google.com/patent/US2969491A
|
| https://patents.google.com/patent/US3034035A
|
| https://patents.google.com/patent/US3667014
|
| (The most powerful motors have always been wound-field designs,
| since huge permanent magnets are extremely difficult to make and
| even more difficult to handle at all.)
| adrian_b wrote:
| All the inductively excited synchronous motors described in
| those patents work due to including semiconductor rectifiers in
| the rotor.
|
| It is likely that today this concept from more than a half of
| century ago can be revived at a much higher level of
| performance, due to the present ability of making optimized
| designs and due to the fact that now much better rectifiers are
| available, e.g. silicon carbide Schottky diodes.
| achr2 wrote:
| There might not be any diodes required if the driver uses a
| very high frequency DC chopper, the smoothing could be purely
| reactance + momentum.
| adrian_b wrote:
| It does not matter whether the driver generates AC or
| chopped DC, when passing through the gap between stator and
| rotor, any DC component is removed.
|
| To provide the DC component needed by the excitation
| current, a rectifier is required, or at least a nonlinear
| impedance, but the latter would have a lower efficiency,
| due to higher AC components that would cause losses without
| providing useful torque.
|
| A brushless synchronous motor which relies on an electric
| excitation current in the rotor (i.e. not on permanent
| magnets, hysteresis or variable reluctance) cannot generate
| the required excitation current when only linear circuit
| elements are present in the rotor.
| ARob109 wrote:
| I suspect this ZF motor is like what is described in this
| paper [1]. An air gapped transformer is used to transmit
| power to the rotor and diodes rectify it. See Figure 1.
|
| This [2] appears to give a good summary of PSM vs ASM vs
| EESM and introduces iEESM (i is for inductive excitation
| instead of brushes, sounds like the ZF motor) at slide 14.
|
| [1] Design of Inductive Power Transmission into the Rotor
| of an Externally Excited Synchronous Machine
|
| https://mediatum.ub.tum.de/doc/1226682/1226682.pdf
|
| [2] https://cdn.vector.com/cms/content/events/2018/vEMOB18/
| 01_In...
| promiseofbeans wrote:
| I saw a video recently of Tesla bragging that they had a new
| motor with only 3(?) powerful magnets in it. This makes me think
| that less magnets is a good thing - can anyone explain to me the
| reason to use less magnets in motors? (To me it just seems that
| less magnets would make it harder to spin with a magnetic field,
| but I'm no engineer).
| moffkalast wrote:
| I think it just dictates the number of poles the motor has? The
| fewer the poles the less torque it has, but higher RPM. Either
| way you have to gear it down for EV use, so I suppose it
| doesn't really matter much in the end, except if it makes the
| rotor less likely to explode.
|
| I would've expected very high pole counts to be more practical
| though, since a lower RPM is more manageable in terms of
| bearings wearing out. On the other hand, steppers have a high
| pole count and their efficiency is crap so maybe they can get
| more power out with fewer poles.
| rawicki wrote:
| Unless you want to chase Tesla with marketing numbers trading
| off torque for something else is almost always a good
| tradeoff.
|
| Modern electric motors are much stronger than most users
| need.
| Farmadupe wrote:
| Steppers are super optimized for being super precise and easy
| to controle while being (relatively) cheap to build.
|
| They have weird "trick" geometry that means you can move the
| rotor to many different angles (tens, hundreds) with far
| fewer stator windings.
|
| The cost of this is really low power and efficincy if you
| just want to spin them.
| mannykannot wrote:
| If having fewer magnets means less rare earth consumption for
| the same performance, then that's a benefit in itself - the
| same one as is being claimed for this motor.
|
| https://news.ycombinator.com/item?id=37454238
| moffkalast wrote:
| > In contrast to the magnet-free concepts of so-called separately
| excited synchronous motors (SESM) already available today, ZF's
| I2SM (In-Rotor Inductive-Excited Synchronous Motor) transmits the
| energy for the magnetic field via an inductive exciter inside the
| rotor shaft. This makes the motor uniquely compact with maximum
| power and torque density.
|
| Permanent-magnet-free would be more accurate, this is sort of
| like a BLDC motor, except that if I understand this correctly
| they use some kind of wireless charging to power coils on the
| rotor? Doesn't wireless charging have only like 70% efficiency?
| twobitshifter wrote:
| https://m.youtube.com/watch?v=43JMIuwVrY4&pp=ygUOSW4gcnVubmV...
|
| A regular BLDC motor is already using induction. See this
| video.
|
| The 70% number you are referring to is for a flat coil through
| a much greater distance than would be needed here. For the new
| design, I imagine another set of coils inside and separated
| from the rotor, and the magnets on the rotor replaced by a
| simple ring. The induction coils would need to be offset to
| produce torque on the ring. Yes, it would be less efficient
| because you are using power to produce the magnetic field.
| However, no rare earth metals are required.
| raverbashing wrote:
| This sounds like it's an induction motor where the inductors
| are on the spinning part (the rotor - or maybe in both?)
|
| People are downplaying this, but I'm not so sure (yes I know
| about synchronous motors, etc), but there sure it is covered in
| marketing fluff (which is not wrong per se - if tesla passes
| gas people would have been all over it)
| agumonkey wrote:
| Maybe compensated a bit by the lack of friction and the overall
| lifespan of the device ?
| Farmadupe wrote:
| I know press releases never describe anything that's actually
| novel, but it looks like they're just describing an asynchronous
| induction motor? I'm wondering if this release is implicitly
| pretending that some "low slip ratio" motor is "basically"
| synchronous
|
| Just guessing, does ZF mostly put out induction motors, and they
| need to make them look less unfashionable so that people choose
| them for new designs?
| westmeal wrote:
| ZF is generally known for gearboxes, a huge amount of
| manufacturers use their transmissions in their cars. New
| corvette uses a zf 10 speed I think, same with vw and BMW.
| [deleted]
| KingOfCoders wrote:
| ZF stands for "Gear Factory" and is owned by the Zeppelin
| Foundation (yes, that Zeppelin) which is onwed by the city of
| Friedrichshafen.
| omnibrain wrote:
| To nitpick a bit:
|
| Yes, it is that Zeppelin Foundation. 1947 the old militarist
| Zeppelin Foundation got dissolved and a new one got formed. It
| is not exactly ,,owned" by the city, but controlled by the city
| and the city is the benefactor, but not for the general budget,
| but for Science, Education, Art, Culture, Sports and some more.
|
| The foundation ownes another Company: Zeppelin GmbH with ~10000
| employees and a revenue of 3.7B. So also not exactly small.
| Zeppelin GmbH is the "real deal". They built the Zeppelins back
| in the day and with their daughter Zeppelin Luftschiffbau GmbH
| they are building the new Zeppelin NT. the 3 current "Goodyear
| Blimps" are not some generic Blimps, but modern Zeppelins.
| codethief wrote:
| And (to my surprise) they are not exactly small:
|
| > The Consolidated ZF Group is represented with 168 production
| locations in 32 countries as well as 19 main development
| locations in nine countries. In fiscal 2022, ZF reported sales
| of EUR43.8 billion with approximately 165,000 employees
| worldwide. The company spent 7,8 percent of its sales on
| research and development in 2022.
|
| https://www.zf.com/mobile/en/company/company.html
| slow_typist wrote:
| Not as big as Bosch but still a first tier automotive
| supplier.
| NovemberWhiskey wrote:
| Every European car I've ever owned has had a ZF transmission.
| windowsrookie wrote:
| And all Zf transmissions had a major design fault up until
| the current 8 Speed. Now they are pretty good. Not only
| European cars use them, many Chrysler/Dodge/Jeep/Ram cars
| have ZF 8 speeds in them.
| nomel wrote:
| > And all Zf transmissions had a major design fault up
| until the current 8 Speed
|
| Any reference or hint? Google brings up nothing obvious.
| userbinator wrote:
| Not sure if parent comment had this one in mind, but look
| up "ZF reverse only" and "no drive after revving engine
| briefly in Park".
| nunyabidnesses wrote:
| I work for zf. There are two large plants in south carolina.
| One that supplies the bmw plant here and another that makes
| transmissions for most of the major auto manufacturers and
| parts for tesla. We have a few thousand employees at the
| plant I work at. They are investing a fair amount of money
| and time in setting up more manufacturing here(US). Fun fact
| I get to ride a tricycle around the plant.
| finnjohnsen2 wrote:
| Germany doing it's thing making the parts everyone needs.
| userbinator wrote:
| Maybe their electric stuff will be better, but unfortunately my
| experiences with ZF transmissions have not been great.
| crazyjncsu wrote:
| Maybe not your experiences, but, to me, their transmissions:
|
| * hastened the inevitable transition away from manual
| gearboxes in cars
|
| * gave a bit of a "last hurrah" to ICE powertrains in general
|
| Quick-shifting, gobs of gears, lockup torque converters, and
| reliable to boot. I don't hear the word "slushbox" being
| thrown around like it was previously to describe automatic
| transmissions. And I credit it mostly to ZF.
| hamburglar wrote:
| As an owner of an M4 with the ZF 8 speed, I can attest that
| it's not a slushbox. It's completely changed my mind about
| how a manually-shifted auto transmission with a torque
| converter can behave, and I don't see any reason to ever go
| back to a true manual. My only real complaint is that 8 is
| too many gears so they are naturally narrower and the car
| ends up being designed around keeping your engine speed in
| a fairly small band, and low end torque suffers.
| scrlk wrote:
| Out of interest, what issues did you have? Most of the time
| when I read a car review, they seem to praise the ZF 8HP
| 8-speed.
| userbinator wrote:
| This is about their automatics, but parts availability
| (especially aftermarket) and service information is
| relatively scarce and expensive compared to e.g.
| GM/Allison. Their bus/truck transmissions also shift quite
| roughly, almost like a manual.
|
| ZF is what I'd consider very stereotypically German
| engineering: optimised for efficiency and cost, at the
| expense of longevity and serviceability, with very little
| margin for overload.
| ricardobeat wrote:
| > stereotypically German engineering: optimised for
| efficiency and cost, at the expense of longevity
|
| I thought German engineering had the exact opposite image
| worldwide?
| seabird wrote:
| There's a difference between what the layman has been led
| to believe by Big Deutschland, and the reality
| experienced by those who actually have to deal with
| German designs. A lot of them are interesting and
| "elegant" on paper, but the good experiences usually end
| there. It feels like the fun factor of the design process
| is what's prioritized most heavily, which is great for
| the designers (and I don't say this facetiously; the fun
| is the #1 reason to do it at all, and I'm glad they make
| a living off it), and not-so-great for the poor fucker
| that has to repair a VW.
|
| That's not to say that they always shit things up. I'll
| take Wago nuts over American style ones any day of the
| week. VW's VR6 engines are a simplification that would
| probably make my life a lot easier if I didn't have to
| buy them with the rest of the VW vehicle attached. There
| is so much more vision coming out of Germany in
| industrial controls than anywhere else it's outrageous.
| Life has its ups and downs, I guess.
| Freestyler_3 wrote:
| Same here.
| weinzierl wrote:
| The commenters saying that this is old news and that magnet-free
| brushless motors have existed for a long time miss the main
| point. ZF claims to have one that is competitive with traditional
| designs utilizing rare earth materials.
|
| Even ten to fifteen years ago the effort German automakers put
| into saving a milligram Dysprosium here and there - not only in
| the drive motor but _every_ electric motor in the vehicle - was
| insane. I 'm out of automotive for a couple of years now, but I
| can only imagine that this pains must have increased
| dramatically.
|
| Because of all this effort, a motor without rare earth metals
| would only have to be nearly as good as the competition to still
| be a huge deal.
| [deleted]
| mschuster91 wrote:
| > Because of all this effort, a motor without rare earth metals
| would only have to be nearly as good as the competition to
| still be a huge deal.
|
| Even if it were not as good, getting rid of the dependency on
| rare-earth materials and their dirty supply chain is worth it.
| hamburglar wrote:
| Indeed. Dirty, expensive, and bottlenecked.
| specialist wrote:
| IIRC, the proper KPI for (EV) vehicles is cost per km traveled.
| Right?
|
| Meaning balancing tradeoffs of performance, cost, weight, etc.
|
| (Not to mention mitigating risks, like sourcing and
| externalities.)
|
| It's fascinating to me, as a lurker, that misc EV OEMs are
| making different choices. Such exciting times.
|
| PS- Why'd you leave the automotive industry?
| weinzierl wrote:
| I always had a strong interest in security and that's the
| direction I developed even when still in automotive. When the
| opportunity came to work for a security company I switched.
| specialist wrote:
| Nice.
|
| The automotive industry needs security skills like yours,
| now more than ever. :)
| ouid wrote:
| [dead]
| adrian_b wrote:
| The most usual kind of motor with permanent magnets, is just a
| synchronous motor, where, in order to remove the power supply
| needed by the rotor windings, the rotor windings are replaced by
| permanent magnets.
|
| Here, in order to achieve the same brushless operation like when
| using permanent magnets, the rotor windings are kept, but the
| electrical current needed by them is transmitted to the rotor
| wirelessly.
|
| For this to work, I suppose that the rotor includes some kind of
| semiconductor rectifiers and the rotor current is induced at a
| frequency much higher than the rotation frequency.
|
| This should indeed have characteristics similar to the permanent
| magnet motors, except that it is not clear if the energy
| efficiency can be equally good.
|
| A permanent magnet rotor is equivalent with a rotor having
| superconducting windings, so it has no losses due to the
| electrical excitation currents (though it may have losses due to
| other causes, e.g. hysteresis and eddy currents).
|
| This motor will have extra losses in the copper windings of the
| rotor and in whatever kind of rectifiers it uses.
|
| Nevertheless, perhaps these extra losses are small, so the
| efficiency can be much higher than that of asynchronous motors
| (like initially used by Tesla) and only a little lower than that
| of the permanent magnet motors.
| londons_explore wrote:
| > except that it is not clear if the energy efficiency can be
| equally good.
|
| There are potentially ways energy efficiency can be better...
|
| It's possible to produce stronger (ie. more flux density)
| magnetic fields with electrical currents than with neodymium
| magnets. Those stronger fields mean flux paths can be shortened
| and (for the same mass of copper), wires can be shortened and
| resistive losses reduced.
|
| However, I haven't done the math to see if those effects are of
| a significant enough magnitude.
| hoc wrote:
| Hm. Can I just buy two of them plus drivers or do I have to order
| a fully custom designed series?
| larkinrichards wrote:
| What would be the impact of this style of motor on regenerative
| braking?
| matanyal wrote:
| Coolio!
| londons_explore wrote:
| Does anyone have a raw materials cost breakdown of motors? Are
| the neodymium magnets actually a big chunk of the cost? Or is it
| more of a "we'll get government grants for inventing a type of
| motor that doesn't require a material that China has strategic
| control over".
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