polluting electric car?

[gildas]

This article is a little abusive, it is not necessarily necessary to have permanent magnets for the electric motors of cars ..

Synchronous motor
Synchronous motors present zero slip. They are the ones manufacturers are now facing: with better torque / weight ratios and power density and higher yields, they are divided into two categories: coils and permanent magnets.
While the coils have a magnetic rotor with currents, the permanent magnet synchronous motors do not need rotor coils. They are therefore lighter and have no longer joule losses to the rotor, the losses to the stator being easy to evacuate.
The latter type of engine may therefore seem superior, but since permanent magnets are, like many rare earths, a material whose supply depends very much on the conditions of economic exchange with China, it is necessary to discuss between the performance of the engine and the volatility of its price ...
While PSA and Toyota are moving towards this technology with respectively Ion and Prius, Renault-Nissan and Bolloré prefer the wound rotor.

https://www.industrie-techno.com/les-se ... ques.42249

[chatelot16]

pleased to see that some manufacturers prefer the coiled exitation, proof that the permanent magnet is not necessarily the best solution

the exitation to magnet seems to save the power of exitation ... but in a well made motor the power of exitation is very weak ... the wound exitation has a big advantage: we can adapt the excitement to speed and to the couple: at high speed the constant exitation of the magnet produces too much loss in the motor: a reduction of the exitation reduces the losses

a varaible exitation widens the range of use of the engine: strong exitation for large torque at low speed ... low excitement for low loss at high speed

the asynchronous motor has a bad reputation because the slip is a loss of power: the 50Hz motor is a big slip because it is optimized to have a big couple of demarage, in direct connection on 50Hz ... but with an electronic variator which adapts the frequency during start-up it is possible to optimize the motor to reduce the slip and one obtains the same output as a wound excitation, with simplicity in addition ... therefore the asynchronous motor remains a good solution

[Leo Maximus]

glad to see that some builder prefer wound exitation

And the use of broom as in the case of the R75 engine of the Renault ZOE ...

Premature wear, ozone production, etc ... not necessarily progress.

[chatelot16]

do not confuse brushes of DC motors that make all the power of the motor, and in addition make switching

in a synchronous motor with coiled exitation the coals only transmit the power of exitation, and in addition there is no commutation, it is rings continuous, and it is used much less ... of course nothing is eternal but alternator energies or synchronous motors are not a weak point

but coal is not the only solution: the asynchronous motor can be seen as replacing the power of exitation transmitted by coal, by a power of exitation produced by the slip ... a quality of realization equal the power of exitation of a synchronous motor is roughly equal to the power lost by slip of the asynchronous motor

we rarely mention the asynchronous motor in the futuristic project because it has the bad reputation of inefficient engine found in 50Hz ... so we speak rather of brushless which says nothing at all about what it is exactly

[Gaston]

And the use of broom as in the case of the R75 engine of the Renault ZOE ...

Premature wear, ozone production, etc ... not necessarily progress.

One should not confuse the "universal" motors (used for example in the majority of vacuum cleaners) which have a blade collector on which brushes rub and which tend to produce sparks as the blades pass, sparks which are effectively a source of brush wear and ozone production, with "wound rotor synchronous" motors where the brushes make contact with uniform rings all around the rotor and without breaking.
In the latter, the brushes wear out very little (in the electric vehicles using them, like the Zoe, the brushes can greatly exceed the 100 200 000 km) and do not produce ozone.

[Leo Maximus]

Very good.

On the forums of exchanges, breakdowns linked to the Zoe's brooms are not uncommon, well before 100 or 200000 km.

And Renault has developed a brush wear evaluation system to prevent breakdowns by ... limiting the power available! See the patent WO2017046502A1. In practice, the eventual failure should occur after the expiration of the warranty. Good idea Renault.

A few years ago, I was thinking of buying a Zoé, but it was mainly the cost per kilometer of the battery rental that dissuaded me.

[chatelot16]

when I see that the game of 4 coal of a big tractor starter costs less than 10 euro, the charcoal of an electric car engine should be smaller and cheaper ... except that I am wary of car manufacturer, well able to invent something too complicated

[Gaston]

On the forums of exchanges, breakdowns linked to the Zoe's brooms are not uncommon, well before 100 or 200000 km.

There was a series of engines with a defective seal that caused oil leakage (from the gearbox) to the motor rotor quite quickly which damaged the brushes (or caused problems with the brush ring contact? ).
In this case, it is not the brooms that have been replaced, but the entire engine.

For me, it does not question the relevance of technology used (which is also used for large electrical machines capable of operating for tens of thousands of hours without exchange of brooms).

A few years ago, I was thinking of buying a Zoé, but it was mainly the cost per kilometer of the battery rental that dissuaded me.

There, however, I fully agree. You have to drive a lot to "make profitable" the rental of battery.

[Leo Maximus]

Toyota invents neodymium-light magnets to advance the electric
Sea 21 / 02 / 2018 - With less rare earths ....

It is a tendency that is accentuated, we go towards magnets high performance without rare earths: https://en.tdk.eu/tdk-en/373562/tech-li ... nce/373504

Between the 2004 Prius II and the 2010 Prius III, the mass of the magnets has already been reduced by 40%, from 1,232 kg to 0,768 kg, while the power increased from 50 to 60 kW.

Toyota hybrids magnets.jpg (107.96 KIO) Viewed 3431 times

source: http://ecee.colorado.edu/~ecen5017/note ... 0Prius.pdf

So mass reduction, increased power and less and less rare earths. The right path.

[Janic]

So mass reduction, increased power and less and less rare earths. The right path.

In appearance, because more cars can switch to electric and more demand will be strong regardless of the technique used and we still turn around. More maintaining, or even increasing the demand for nuclear power mainly with all its dangers. Do not be fooled the race for energy moves only at all polluting immediately by fossil fuels at all nuclear pollutant for the next generations.