pyrlix wrote:Which is totally wrong
Electric engines dont have constant torque - they have constant power. A 3kW electric asynchronous engine always has 3kW, and the most used type of electric engine is the asynchronous 3-phase AC induction motor. Its the one with the best torque curve - the reason they have constant torque in cars is that induction motors have a kinda high starting torque that can rip the gearbox apart - it can be 3x higher than the normally rated torque.
I think the Tesla S 60 uses a max 225kW Engine - thats the power it has from 5000-8000RPM - which is the maximum power the engine has. As i already said, AC motors have constant power... and 225kW@2000RPM results in... 1070Nm Torque! And at a normal "idle" it would be twice as high, so do you really want to construct a gearbox that can withstand the massive torque, or just take a way cheaper power limiting unit ? Trust me, its easier to take a frequency converter that has a power limiting feature instead of a normal frequency converter and a ultra-durable gearbox.
Cheers
Indeed. Continuing with the Tesla example (uh oh, you got me started on Tesla!), what people constantly make a mistake about is that they think that the car has max horsepower from 0 RPM, whereas it actually has max torque from 0 RPM. If you look at the dino run they did of a P85+ here (
https://www.youtube.com/watch?v=xVmdr5nUArQ), by looking at the chart you can see how the horsepower builds continuously. Torque is not displayed, but I believe it is at maximum from 0-5200 RPM.
Also, fun fact about these Tesla cars (Roadster and Model S): Both were supposed to have a two speed rather than one (which would massively increase the top speed), but the instant torque kept breaking the gearbox.