Formula E

[Tim.Wright]

Direct drive does not make full use of the electrical system.

In what way? This doesn't make sense. Of course it does/can.

Direct drive runs the engine through all of the motor's operating range - including parts where you are not at you peak power output.

Adding gears allows you to stay in that "sweet spot" where power is at its maximum.

For a road car, staying in the peak power range is of dubious importance. For a race car it's obviously essential.

Here is an (unverified) engine curve I found on the Tesla which shows the disadvantage of direct drive:

From here: http://www.teslamotorsclub.com

[mzso]

Direct drive does not make full use of the electrical system.

In what way? This doesn't make sense. Of course it does/can.

Direct drive runs the engine through all of the motor's operating range - including parts where you are not at you peak power output.

Adding gears allows you to stay in that "sweet spot" where power is at its maximum.

For a road car, staying in the peak power range is of dubious importance. For a race car it's obviously essential.

Here is an (unverified) engine curve I found on the Tesla which shows the disadvantage of direct drive:
http://www.teslamotorsclub.com/attachme ... 1370283832
From here: http://www.teslamotorsclub.com

I understand why torque drops (it's basically power / rpm). But why does power drop above some rpm?

(I also never could understand why can't motors be efficient in a broad range at low rev/power/torque levels too)

[Tim.Wright]

I have a basic knowledge of electric motor fundamentals - so I will have a crack at answering.

It all comes from the way the torque is created in the motor. The torque is more or less proportional to the current in the windings (via the motor torque constant in Nm/Amp) and the current is more or less proportional to voltage applied to the windings. However, of the voltage which arrives from the power supply, not all of it makes its way across the windings because of the back emf of the motor. The back emf is a voltage which is proportional to rotor speed via the back emf constant in V/RPM and subtracts from the supply voltage.

So as the RPM increase, the back emf increases until it completely cancels out the supply voltage and you get zero current therefore zero torque. At the other end of the scale, at zero RPM, you have zero back emf and theoretically the full motor voltage and therefore torque is available.

So the theoretical torque/speed curve is a downward sloping line that starts at the peak torque (coming from having 100% of the supply voltage creating current) down to a point of zero torque at the speed which corresponds to the speed at which the back emf equals the supply voltage.

In practice there is a limit to the maximum current the motor can support which comes down to the thermal capacity of the windings. For this reason the theoretical peak torque can't be reached because the required current would be so high that the stator will weld itself to itself.

So what you see in the end (nicely demonstrated in the tesla plot) is a constant torque (corresponding to the winding rated current) which then drops off at high speed as the emf starts cancelling out your winding voltage.

[Sombrero]

https://www.youtube.com/watch?v=C3mQYghHmAU

Fantastic racing - really !

[bdr529]

https://www.youtube.com/watch?v=C3mQYghHmAU

Fantastic racing - really !

It's funny I don't mind watching the races, I just find qualifying lacking something, maybe it's the absents of engine noise

[Andres125sx]

It has always shocked me when I read comments like that.... Even when I also enjoied V10 sound, sound is just that, sound, racing is a lot more than that so when I read some comment like that of people saying they don´t watch because of the sound, I can´t stop myself thinking if that person really like racing.


Also, I like that electric sound more and more each time I watch it, it´s the sound of the future, no screaming, no deafening... just a ´technological´ sound if that makes any sense. And btw, it allow you to hear a lot more interesting sounds, like tires, wich show you the driver style. Engine sound is monotonous, always the same, and tell you nothing about the driver or driving style. I much prefer hearing the tires, wich tell you a lot about the driver and his driving style

[bdr529]

It has always shocked me when I read comments like that.... Even when I also enjoied V10 sound, sound is just that, sound, racing is a lot more than that so when I read some comment like that of people saying they don´t watch because of the sound, I can´t stop myself thinking if that person really like racing.


Also, I like that electric sound more and more each time I watch it, it´s the sound of the future, no screaming, no deafening... just a ´technological´ sound if that makes any sense. And btw, it allow you to hear a lot more interesting sounds, like tires, wich show you the driver style. Engine sound is monotonous, always the same, and tell you nothing about the driver or driving style. I much prefer hearing the tires, wich tell you a lot about the driver and his driving style

What's shocking ? that I was honest in my opinion.
This makes you think I don't like racing even though I did say I watch the races,
I just said that I felt that "qualifying was lacking something for me, and maybe it's the absents of engine noise"

Instead of asking why. You go off on one of your "electric is the wave of the future" diatribes,
while at the same time using these phrases "I much prefer" and "I like that" both of which are opinion based phrases

It's a shame, in a 21 word post in which I said I watch the races you only read absents of engine noise
and then equated that to "I don´t watch because of the sound " and thus "I don't like racing"

That's the true essence of closed-mindedness

[Andres125sx]

It has always shocked me when I read comments like that.... Even when I also enjoied V10 sound, sound is just that, sound, racing is a lot more than that so when I read some comment like that of people saying they don´t watch because of the sound, I can´t stop myself thinking if that person really like racing.


Also, I like that electric sound more and more each time I watch it, it´s the sound of the future, no screaming, no deafening... just a ´technological´ sound if that makes any sense. And btw, it allow you to hear a lot more interesting sounds, like tires, wich show you the driver style. Engine sound is monotonous, always the same, and tell you nothing about the driver or driving style. I much prefer hearing the tires, wich tell you a lot about the driver and his driving style

What's shocking ? that I was honest in my opinion.
This makes you think I don't like racing even though I did say I watch the races,
I just said that I felt that "qualifying was lacking something for me, and maybe it's the absents of engine noise"

Instead of asking why. You go off ....

No, you provided your opinion, and I provided mine, that´s all

No shame if I understand you said FE is lacking sound. That´s what you said, and I disagree. Where´s the problem? That´s the point of forums, isn´t it?

[bdr529]

My problem is what you said "I don´t watch because of the sound " and thus "I don't like racing"

This is my initial quote, Where does it say I wont watch Formula E because there is no sound

It's funny I don't mind watching the races, I just find qualifying lacking something, maybe it's the absents of engine noise

[Andres125sx]

I got "I don´t mind watching the races" as if you can watch it, but don´t enjoy it too much because of the absence of noise. If that was not what you were refering to, then excuse me, I misunderstood it

[ChrisF1]

When I am watching a really good battle, my mind becomes oblivious to noise and I go purely visual.

[bdr529]

ChrisF1 has brought up a good point and I would tend to think that's maybe the reason,
I do seem to notice how bumpy the street courses are during qualifying, and don't seem to notice it during the races
That's why I used the word maybe because I don't know exactly why

This is not a slight on Formula E, I feel the same way about other forms of motorsports when it comes to qualifying
I will catch almost every NASCAR race on tv this year baring other commitments, but I know I will not watch one second of NASCAR qualifying because I find it boring
The same thing when F1 had single car qualifying. I didn't find it very exciting to watch one F1 car driving around by itself and so I didn't make a big point of getting up early to watch it, I would just tape it and speed though it for highlights later,
But I still got up early every Sunday to watch the race live.

To clarify my first post, It's just qualifying and only qualifying that I think is lacking something. Not the race

[Andres125sx]

I loved that qualifying, it was the only chance to watch the slow cars, and it was great to compare different cars and drivers

Add to that it was a lot more exciting because a mistake had tough consequences for the grid position, unlike now that they have at least two attempts so there´s no tension

[FW17]

Formula E is riding on the green tag finding promoters to fund expensive city races around the world

Any idea of the cost of a race that FE charges to promoters?

It is sad that FE manages to go around the world but Indycar cannot manage even a road trip outside US borders.

[scarbs]

Official FE tech video. I had a small part in this, hopefully they'll do lots more, if it's seen as a success.

https://youtu.be/8XMVJ3fjOGg