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.
You can also make squirrel-cage rotors that are auto-inductive in the sense that they resist slip from the rotating field of the stator. This is also extremely simple to manufacture and doesn't require driving separate fields or anything similar.
This is mentioned in the parent page, where it is also mentioned that their disadvantage is a lower energy efficiency than either electrically-excited synchronous motors or permanent-magnet motors.
The lower efficiency means a lower range for the same battery, which is why the companies that have used them in the past, like Tesla, have abandoned them.
Permanent-magnet motors have the highest possible energy efficiency, followed by electrically-excited synchronous motors, than by the induction motors mentioned by you.
Both permanent-magnet motors and induction motors do not contain parts that need frequent maintenance, while this property is more difficult to achieve for electrically-excited synchronous motors.
I am a little surprised that Renault is only claiming a drive cycle efficiency of 92% (unclear for which drive cycle). It is possible to design EESM with brushless high frequency rotating transformers and rectifiers for WLPT drive cycles with greater than 94% almost 95% efficiency.
In most EVs motors are watercooled, so that energy can indeed be scavenged – problem is, during low-speed driving, the heat output is not high enough to get noticeably above ambient temperature.
Thermodynamically, heat is waste energy. EVs are so efficient that scavenging isn’t practical anymore; I’m not sure the temperature gets high enough to usefully extract the heat energy for heating. ICE cars obviously produce mostly heat so getting a radiator hot enough to heat the cabin is very easy
It's a small difference, but if you had a choice between "more efficient AND less maintenance" and "less efficient and more maintenance" then it's easy to see why the permanent-magnet solution is preferred.
The actual alternative is induction motors, which are just a bit less efficient than PMSM and otherwise basically the same. Except that the frequency fed to them isn't exactly proportional to speed.
They've been used to great success since we had the needed power electronics to drive the electric trains of Europe.
I often also wonders if ideological zealots ever thinks of this passage while pushing their agenda for control:
...and it was allowed to give breath to the image of the beast, so that the image of the beast could even speak and cause those who would not worship the image of the beast to be killed.
Also it causes all, both small and great, both rich and poor, both free and slave, to be marked on the right hand or the forehead,
so that no one can buy or sell who does not have the mark, that is, the name of the beast or the number of its name.
Those who would think of such a passage (or any biblical passage) and those who push for a total-control agenda are disjoint sets.
Communism and fascism were both fueled by atheism (either explicit or functional), not a Judeo-Christian worldview.
"Ohne Gott und Sonnenschein bringen wir die Ernte ein." (Without God and without sun, we will get the harvest done.) - the slogan of East Germany in 1975 when people were hungry and it kept raining during harvest.
that's not Christian though (in the sense that their beliefs are not scriptural and not subjected to scriptural review)... it's something else, and it's really ugly.
13 Let everyone be subject to the governing authorities, for there is no authority except that which God has established. The authorities that exist have been established by God. 2 Consequently, whoever rebels against the authority is rebelling against what God has instituted, and those who do so will bring judgment on themselves. 3 For rulers hold no terror for those who do right, but for those who do wrong. Do you want to be free from fear of the one in authority? Then do what is right and you will be commended. 4 For the one in authority is God’s servant for your good. But if you do wrong, be afraid, for rulers do not bear the sword for no reason. They are God’s servants, agents of wrath to bring punishment on the wrongdoer. 5 Therefore, it is necessary to submit to the authorities, not only because of possible punishment but also as a matter of conscience.
We also had Christian fascist governments, like my home country Spain. One of the official doctrines of Franco's government was deemed "National Catholicism" :/
Tuition assistance per kid isn't going to cut it. That doesn't solve any other problem of: unaffordable housing, unaffordable child care, a hustle culture that mandates people be productive and climb the career ladder to barely get ahead, the loss of complete freedom and free time, etc.
both parents having to work fulltime, and the severe hit to your career if you pause working while the children are young is the primary hindrance in my view.
Yeah the career thing is huge, and also just a general lack of flexibility at a lot of companies. Expectations to be in-office, butt in chair for 8 hours a day, etc.
When you have kids, you need the freedom to just get up and leave at any time to respond to things. School calls cause your kid is sick, emergencies, you name it. You gotta be there and be available for them, and we need a culture to where that doesn't become damaging to your career, and enough worker protections in place to where you cannot face disciplinary action for that.
they didn't just happen, they were expected and demanded. there was social pressure to have children. that's still true in china today. some not yet grandparents put a lot of pressure on their children to give them grandchildren (sometimes very violently too), and i remember a comment in an earlier thread where someone told about the experience of their parents or grandparents where the local pastor was having a concerned talk with a childless couple.
Is that enough though? Women change their entire bodies, sacrifice years of their lives, and go through considerable stress to have a baby. And at the end, the benefits of that ordeal are not clear.
Society would need to offer something to offset all those costs.
> Women change their entire bodies, sacrifice years of their lives, and go through considerable stress to have a baby.
"Humans extinct, women most affected"
Pretty amusing how it's always framed as some terrible burden on women to justify more gibs. As if they aren't also the beneficiaries of society thriving and men never make any sacrifices for society. Or that, well, women also "benefit" from reproducing in the Darwinian sense.
Because it will be very messy and involve a lot of suffering if unmanaged.
The population just doesn't disappear, it can pretty quickly shrink in just a generation or two leaving huge amounts of infrastructure unmaintained and falling apart with huge amounts of debt that will ensure what remains of society ends up in chaos.
That and the most likely part of the population to shrink is the ones we consider more stable and rational. Cults and religious breeding groups will increasing become the majority of the population leading to some 'interesting fun times'.
> like guaranteed tuition assistance per children born?
It needs to be a massive package of subsidies.
Children used to be a private good. Child-labor laws and the cost of raising kids flipped that. Children remain a public benefit, but that benefit is realized without paying for the cost. In essence, the cost of all prenatal, neonatal and pediatric healthcare; schooling; the opportunity cost in career and recreation the parents incur from having to raise kids; and the direct costs of feeding, clothing, nannying, et cetera children need to be directly subsidized, probably with a cash bonus on top.
In America this would probably be a ca. $50k/child benefit at the low end.
the reason we have been fighting teen pregnancy is because as a society we decided not to support young parents, and because teen pregnancy happens out of wedlock with the fathers usually disappearing. i believe historically this comes from the fact that mothers used to stay at home, so as soon as you had a child you would not go to school anymore.
we could decide otherwise and create structures where young people, still in highschool or studying, are at the same time able to live together and have children.
> because teen pregnancy happens out of wedlock with the fathers usually disappearing
Usually disappeared. Once DNA tests were invented, it became straighforward to go after them. Underrated breakthrough to support children and single mothers.
In the US, there is ~$115 billion worth of child support debt outstanding. Even with DNA testing, we’re not going after the folks who aren’t supporting their offspring, mostly because they are low income and have nothing to take to satisfy these debts.
> Yet, 2020–2022 data in the KIDS COUNT® Data Center reveal that just 23% of U.S. female-headed families reported receiving any amount of child support during the previous year (down from 26% in 2018–2020). Female-headed families refer to unmarried women living with one or more of their own children under age 18, which may include stepchildren and adopted children.
> One in three kids — nearly 24 million kids total — lives with a single parent, mostly single moms. In fact, according to 2022 Census Bureau data, of the 10.9 million one-parent families with children under age 18, 80% were headed by a mother. This makes women the more frequent custodial parent and the majority of those who need child support.
While fertility rates are down, roughly 40% of annual pregnancies in the US are unintended (per the Guttmacher Institute). There is still much work to do to drive down the rate of unwanted pregnancies.
yes, but what would be the point? they are still in school too, have no work and no income, so they are not going to pay child support either. the girl is better off without such a guy.
my point is to support couples who actually want to be together to build a family. getting pregnant from a guy you messed around with is not a family. the goal is to prevent unwanted pregnancies by making it easier to have wanted ones in a supportive environment. hunting down a guy who didn't mean to get you pregnant after it happens unintentionally doesn't accomplish that.
In some tribal societies, everyone fucks everyone, whatever children are born are born, and since nobody knows who the father is they all care for all of them collectively.
Is it possible this is actually a better model than the nuclear family?
Even if it is, there's never any guarantee that something which works at the scale of a tribe can be transplanted to a nation of millions.
To a limited extent, the school system itself is how we collectively care for the next generation. How far can it be pushed in the direction you ask about?
one idea is multi family homes. the idea is that instead if each family having having all their own space for themselves, you have a lot of shared spaces. consider that you need to be private, that's your bedroom and a bathroom. but you can share the kitchen, the living room, a play room, a reading room, a tv room. you don't have to share everything. there is a lot of flexibility in how you arrange the space, but the overall idea is that you have multiple families together, and because you share some things you also get to know each other better and kids can run around and feel at home everywhere. if you need a babysitter because you want to go out, you can simply check in with one of the other families if they are at home, and ask if it is ok if you go out.
the two main benefits are that parents get to know each other better, just like they would in a village, instead of being anonymous like we are most of the time, barely knowing who our neighbors are. and the sharing of resources. my dad loved books and music. i basically grew up in a library. it was nice when i had to make a school report that required some research, but it would not have hurt if those books would have been shared with a lot more people. ok, we have public libraries too, but you get the idea. by sharing resources you are able to get a lot more things that you would not be able to get if you lived alone.
I've lived in a few things such as you describe and… it's variable. We kinda need a culture that fits them, as people right now are all over the place in terms of responsibility for shared spaces.
Not saying it can't be done, only that this is harder than the Nike slogan (just do it).
you won't get an argument on that from me. it certainly takes work, good will and a desire for harmony. it takes a close community. that's why my life focus is on community building.
can you share more about the spaces where you lived?
> can you share more about the spaces where you lived?
The first few places were all at university: shared kitchen, shared laundry facilities, etc. and most had shared showers.
After I graduated, one of my partners was living in a HMO, I can't find any pics, but if you imagine a dozen big private rooms surrounding a central living area, a bunch of normal sized shower rooms also attached to it, and also a big communal kitchen with enough cupboard space for everyone to have their own.
More recently, though still 8 years ago, an older family member got Alzheimer's and both I and my brother wanted to help look after her, which ended up overcrowding the place with a normal UK semi-detached home having me, them, and my brother's whole family living in it while the builders slowly converted the garage into a granny annex for her, with its own min-kitchen and bathroom; by the time the annex was ready, we were all too stressed out and I made the move to Germany that I'd delayed in order to help look after her.
> saluton... ;-)
Ankaŭ Saluton! Mi ĝojas, ke iu legas mian uzantoprofilon ^_^;
Yes I wonder why. Teen pregnancy sounds so amazing and inconsequential for individuals and societies alike that teens should just be inoculated as a rite of passage or something...
compared to the alternative, it definitely is. The problems with it are mostly artificial ones our society created. If you were God and redesigned human society from scratch, why wouldn't you have them procreate in their most healthy, fertile, and horny years?
Because teenagers are not known for having the best judgement? Because parenting comes with commitments and obligations that, early in life, conflict with other things that are seen as desirable for a well functioning society (education, equality, opportunities)? Having more experience in life generally makes you a better/better-prepared parent?
Don't read me wrong, I'm not stating that the current economic/social pressure is good at producing healthy/happy parents/families, it just doesn't seem good either to turn teenagers into parents. The "sweet spot" probably lies in between, and what you say is very much an appeal to extremes.
Why did people want to have them in the past, and what shifts do you think could undo industrialization enough to return to that?
The economic value of kids and the relative surety that kids will provide for you in your old age are I think very hard to reclaim now, and that was a pretty strong motivator for most of history. You could end all retirement funds and pension systems and so on, maybe?
Most people are biologically wired to want children. "Survive and reproduce" is pretty much the driving motivation of all living things. Most children weren't conceived as a carefully planned retirement strategy. No cost/benefit calculation is required to convince most people to have children, but you can certainly force them into a position where they have to start thinking in those terms. We've just hit a point where societal and environmental factors are discouraging people from doing what they'd normally do.
Hard wired to want children and hard wired to want sex are two very different things.
When given the choice there are plenty of people putting the latter over the former, and the number of women stuck at home while their husband went out to have affairs suggests the reality of kids doesn't actually interest most people. Plenty of folks just want a status symbol, not the responsibility of raising a child.
I think just about everyone wants more sex than children. That said, many people would love the responsibility of raising a child but don't feel like they can afford it.
I don't mean it as a cost benefit thing, but people thinking that family is important, that they want and need family there for them in their old age, and so on.
The need for all of that is considerably different in modernity and more people choose to live without their family close by, and certainly don't depend on them for housing and care as often?
how about making your pension depend on the number of kids? take an average pension now: X=100%, take half of it as a base, and then add a quarter or one fifth per child. so a childless person gets half the current pension, 1 child gives you 75% or 70%, 2 children 100% or 90%, 3 children 125% or 110%, etc...
Sounds good, until you start arbitrarily punishing people who, for one reason or another, just can't have kids (reasons can be many, for one, biology is a bitch).
that's a defeatist attitude. it's not like we can't make exceptions. or arrange for other ways to earn your pension. besides, if you don't have children you get more time to work, so you pay more, which means, the benefit for parents is actually offsetting lost work time.
which is another approach. how about for each child you get automatically accounted a number of years of payments as if you had earned money. if it takes 30 years of work to earn enough for a decent pension, and every child counts for 5 years then 3 children would allow you to get the same pension with only 15 years of work. how is that?
btw, the global infertility rate is 5%. the global disability rate is 10%. those people are also affected by not being able to work. in other words, 15% of the population are unable to fully contribute to pension funds. where a full contribution means work and having children. but making children a pension contribution actually helps a number of disabled who are still able to have children. so now they are able to contribute more than they would if we ignored children as a contribution.
seriously, this constant shooting down of ideas just because it appears that one group is disadvantaged is tiring. try thinking a bit more creatively and help come up with a solution.
in germany education is free, and some places also offer free childcare. parents get $300 per child per month in financial support regardless of income. and yet all that is still not enough.
well, i did say it's not enough, but i disagree, if you assume free childcare, then the real cost according to statistics is not much higher than that because the bulk of the cost in those statistics comes from expensive childcare, yet, even free childcare does not help to motivate people to have more children.
https://www.youtube.com/watch?v=5E7kBOH9owI
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