191–200 of 231 posts
Earlier quoted context omitted.
25% every journey, or 25% over the lifetime of the car? Neither seems really believable but I don't understand how else you would measure this.
25% of cars. It was... not good.
This technology does show that you should never give up on industry, research, development and building on shore.
Unfortunately, their Web page does not say a single word about the important problems of their motors. The electrically excited synchronous motors have been known forever, but they had not been used in EVs because of 2 disadvantages. The first is that traditional EESMs require brushes, i.e. sliding electrical contacts, which are worn out by friction, so such motors require frequent maintenance for changing the brushe…
Not sure how familiar you are with Renault, but “maintenance problems” pretty much sums up a lot of older Renaults.
I think if we take french cars (Renault/Peugeot/Citroen) in general, most major reliability issues have been on diesel cars exhaust gas recirculation systems due to strict european emissions and they are far from the only brands suffering from that.
German cars were known for their great reliability in the early 90's but in later decades had all sort of electronical gremlins.
Also I think regardless of their actual current reliability, some brands or models attract on average different kind of owners which impact how actual services are followed, if the car is stored inside or outside, if the owner take care or not of warming up the engine in the morning or floor it while cold, and the general care they apply to it.
Earlier quoted context omitted.
> so such motors require frequent maintenance for changing the brushes. Define frequent. I maintain machinery with brushes so I have a decent idea of what life span should be depending on the environment. If the housing for the slip ring setup is well protected from dirt and the slip rings aren't cleaned by a cave man you can get a few years of life from the brushes.
If the desired location for this is a car, then a few years of life that requires half disassembly of a motor isn’t going to work.
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only replying to the first link: isn't sourcing (buying or manufacturing locally) parts for Chinese cars made in Europe a good thing?
It is, but the PRC has been pushing back against sourcing from within Europe and only intends to use CDKs to assemble EVs. This is what the EU is pushing back against. What EU states are now lobbying for is if BYD wants to sell an EV in the EU, it should include European originated parts. Just assembling a knockdown kit in Hungary whose parts were all manufactured in China is not "Made in Europe". If BYD or MG wants…
Can you share any details on this? Is something I've rarely seen discussed
Unfortunately, their Web page does not say a single word about the important problems of their motors. The electrically excited synchronous motors have been known forever, but they had not been used in EVs because of 2 disadvantages. The first is that traditional EESMs require brushes, i.e. sliding electrical contacts, which are worn out by friction, so such motors require frequent maintenance for changing the brushe…
> such motors require frequent maintenance for changing the brushes. "Frequent" is all relative. The Renault Zoe, 10y ago, was already using a synchronous engine with wired rotor. And most were going over 150kkm without any issues nor brush changes. > because the electrical currents that circulate through the rotor windings must generate heat Currently stator heat in wired synchronous engine is less a problem than in…
Unfortunately, their Web page does not say a single word about the important problems of their motors. The electrically excited synchronous motors have been known forever, but they had not been used in EVs because of 2 disadvantages. The first is that traditional EESMs require brushes, i.e. sliding electrical contacts, which are worn out by friction, so such motors require frequent maintenance for changing the brushe…
It depends.
With PM motors if you exceed the Curie temperature, the magnets lose their magnetism. Also one can control the rotor excitation current on EESMs so core saturation is less of an issue compared to PMSMs.
The brushes are also quite long lasting and easy to change on a good design so maintenance is not as a big of an issue.
ASMs are even more robust but they have lower power density and efficiency but are better for coasting.
There is also the SynRM which uses an unwound rotor with flux barriers (cutouts) that aligns with the stator flux, no magnets needed. It's basically as robust as the ASM but without its lower efficiency disadvantages and also no brushes, at the cost of more complex power electronics and lower speed noise.
Earlier quoted context omitted.
> so such motors require frequent maintenance for changing the brushes. Define frequent. I maintain machinery with brushes so I have a decent idea of what life span should be depending on the environment. If the housing for the slip ring setup is well protected from dirt and the slip rings aren't cleaned by a cave man you can get a few years of life from the brushes.
If the desired location for this is a car, then a few years of life that requires half disassembly of a motor isn’t going to work.
Broader point is this: Middle East created oil crisis back in 70s. Since then US economy has grown enormously while it's still using pretty much same amount of oil, imported or otherwise. They shot themselves in their foot. Iran is doing this now, telling the world to avoid Hormuz. They will learn to do that. China is doing that by blackmailing countries with rare earth. Answers will be found. Especially as some of f…
Germany spent enough on solar to have nuclear power for winter heating and instead they get nearly nothing from it when energy (note I said Energy not Electricity) demand is the highest: winter heating.
Now, if they had put that solar in North Africa and ran cables, sure, but they didn't. Or if they did Drake's landing solar storage, that would also work. But they spent a fortune only to still be completely dependent on fossil fuels and are destroying the economic base because of the cost.
Unfortunately, their Web page does not say a single word about the important problems of their motors. The electrically excited synchronous motors have been known forever, but they had not been used in EVs because of 2 disadvantages. The first is that traditional EESMs require brushes, i.e. sliding electrical contacts, which are worn out by friction, so such motors require frequent maintenance for changing the brushe…
Munro took apart a Nissan Ariya which has this exact kind of motor. The maintenance is basically removing a tiny cover and replacing the tiny and cheap carbon brushes every 100k km or more. It's basically cabin filter level maintenance. And they said that PMSM motors are more efficient at low RPM, but their coils get saturated at higher RPMs meaning they lose efficiency at highway speeds (which actually affect the ra…
This seems like a big disadvantage. Highway is exactly where EVs fare worst compared to ICE cars.
I wonder if this could be solved by introducing a gearbox?
I know the new Mercedes CLA (EV) has two gears, the second gear being optimized for highway speeds. But I don't know whether it's related to this.