Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Electric motors with no rare earths

renaultgroup.com

Post reply on HN
Print view View original

61–70 of 231 posts

Re: Electric motors with no rare earths

#61

Post by xeonmc »

userbinator wrote: post #38

A historical pioneer in the complex technology of electric motors without magnets Those who know the history of electric machines will find the title and verbiage very amusing. Motors with no permanent magnets were the first practical ones, and at this point wound-rotor motors are over a century old. It's worth noting that some of the biggest motors have always been designed this way, because the size of magnets requ…

What advantage do permanent magnets provide that it isn't the case that all motors are made without them?

Re: Electric motors with no rare earths

#62

Post by fnord77 »

PedroBatista wrote: post #11
bgarbiak wrote: post #4

BMW also makes rare-earths-free motors for their EVs and - at this very moment - theirs are far more advanced. They offer almost twice the power (up to 300kW vs 160kW) and are on a 800v architecture.

The cheapest EV model Renault sells is around €20K, the cheapest BMW EV is around €65K. It's safe to say the companies are not in the market bracket, no?

same order of magnitude :)

Re: Electric motors with no rare earths

#64

Post by sitharus »

xeonmc wrote: post #61
userbinator wrote: post #38

A historical pioneer in the complex technology of electric motors without magnets Those who know the history of electric machines will find the title and verbiage very amusing. Motors with no permanent magnets were the first practical ones, and at this point wound-rotor motors are over a century old. It's worth noting that some of the biggest motors have always been designed this way, because the size of magnets requ…

What advantage do permanent magnets provide that it isn't the case that all motors are made without them?

A lack of wear components.

A permanent magnet motor uses permanent magnets on the rotor, but an electrically excited synchronous motor has an electromagnet on the rotor. This requires a rotating electrical contact which has normally been made with slip rings and carbon brushes. These wear over time and need replacement.

Most large electric generators are externally excited synchronous generators using carbon slip rings, so it's a well understood field.

This can be made contactless using inductive coupling and a rectifier - since inductive coupling needs AC but the excitation coil needs DC - at the expense of some efficiency.

You can see the efficiency difference - Renault claim 92% efficiency but permanent magnet motor EVs have touted efficiency over 95% in the motor.

Re: Electric motors with no rare earths

#65

Post by IlikeMadison »

alephnerd wrote: post #5

Mentioned in another HN thread [0]: They're also used by Nissan [1], BMW [2], and Indian EVs [3]. European firms like ZF, Valeo, MAHLE, and Schaffler along with British firms like AEM have been working with their Indian JVs as well as Indian players like Sona Comstar and Sterling for a couple years now to integrate supply chains for mass-producing EESMs. EESMs as well as the larger OEM story played a role in helping…

No, and it was mentioned by the consortium of European cars manufacturers after the joint press release with Der Leyen herself: the implementation of factories and research centers in India is solely to be able to sell on that market. It is the exact same process that happened with China in the past. The exact same also happened with Airbus.

You are also wrong on the market importance for Renault. For 2024, France was the biggest, followed by Italy, Turkey, Spain, Germany, Brazil, UK, Morocco, BENELUX, Romania, Poland, Netherlands and... #13 India with 0.9% market share...

Supply chains didn't change at all, in fact it did the opposite, and Europeans won't rely on anything Indian made for the near future, as local re-industrialization is already acted on and even accelerated since the pandemic.

Production numbers across all manufacturers even Volkswagen (which was unexpected) show the number of cars manufactured in Europe increased in the past 2 years.

Electric cars in Europe mostly come from China, the US and European brands. Nothing Indian-made, not even parts.

Re: Electric motors with no rare earths

#66

Post by IlikeMadison »

analogpixel wrote: post #22
alephnerd wrote: post #5

Mentioned in another HN thread [0]: They're also used by Nissan [1], BMW [2], and Indian EVs [3]. European firms like ZF, Valeo, MAHLE, and Schaffler along with British firms like AEM have been working with their Indian JVs as well as Indian players like Sona Comstar and Sterling for a couple years now to integrate supply chains for mass-producing EESMs. EESMs as well as the larger OEM story played a role in helping…

Not sure why this was voted down, it was the most useful comment here. does Nissan still use these motors, the car in the linked article has been discontinued, and then only real info I can find on their site about the leaf is about their ROCKIN' bose sound system/s

Because it's grossly untrue and backed with propaganda slop articles. I suspect this is a bot.

Re: Electric motors with no rare earths

#67

Post by Rapzid »

sitharus wrote: post #64
xeonmc wrote: post #61

Earlier quoted context omitted.

What advantage do permanent magnets provide that it isn't the case that all motors are made without them?

A lack of wear components. A permanent magnet motor uses permanent magnets on the rotor, but an electrically excited synchronous motor has an electromagnet on the rotor. This requires a rotating electrical contact which has normally been made with slip rings and carbon brushes. These wear over time and need replacement. Most large electric generators are externally excited synchronous generators using carbon slip rin…

To a layman that seems like a really small efficiency tax if you can't get your hands on the magnets for some reason.

Re: Electric motors with no rare earths

#68

Post by andwur »

Quarrel wrote: post #60
bgarbiak wrote: post #4

BMW also makes rare-earths-free motors for their EVs and - at this very moment - theirs are far more advanced. They offer almost twice the power (up to 300kW vs 160kW) and are on a 800v architecture.

Which is quite the contrast to Mercedes new axial flux electric motor, which goes all in on rare earths- the design relies on the highest end high-grade permanent magnets. Still, presumably Mercedes ambitions are for few motors than BMW or Renault.

Vastly different target market and/or features there. Mercedes are chasing maximum power density, minimum weight for high performance deployments, with seemingly little concern for cost or supply chain.

Renault is going after the consumer market with these motors, where minimising cost and maximising availability is more important than pushing past 95% efficiency or cramming a 700kW power output in a motor that is small and light enough to fit inside of a wheel hub.

Re: Electric motors with no rare earths

#69

Post by cyberax »

somat wrote: post #39
dmitrygr wrote: post #2

Seems to be: replace permanent Nd magnet with an electromagnet.

There is something... weird about this. this tech has existed.... a long time. And I am not familiar with what is common in electric cars so may be missing something obvious but thought this was already how it was done. let me explain my limited understanding. With ac motors electromagnets can be used in the rotor. there is even a super clever way to do it where the electromagnet in the rotor is driven wirelessly via…

AC motors are not magic. The core is essentially just a coil with one turn, so it can generate only a very limited magnetic field. So they have to be bulkier for a given power density and generally slightly less efficient.

Re: Electric motors with no rare earths

#70

Post by maxerickson »

ahartmetz wrote: post #49
isopede wrote: post #43

Does regenerative braking work with a motor like this?

After watching a Munro video about it, I see your point. In the motor shown, the rotor gets its magnetic field simply by inducing a current and a field in it in reaction to the stator's field. There are no electromagnets in the rotor like I expected. In that case, I'm not sure either... I'd say more likely than not but it's complicated since the stator basically needs to induce a field and at the same time recover en…

There are electromagnets in the rotor, it is directly energized.
Post reply on HN