Electric motor characteristics and curves

[Jozeph]

Hi! I've been looking for proper full-load curves for Tesla Model S and I've found that at the speed of 40 mph (approximately 64 km/h) car almost gains full power. This looks pretty strange to me, because speed continues to rise. As I know, there is no gearbox on Model S and the ratio in the gear unit is constant. So, why do we see increase of speed as the power and torque go down? As I see it, you can only do it by changing electric motor rpm. So, how does Tesla changes them? Do we have any curves (like rpm/power/torque) that describe it?

 

[arnis]

To reach gentleman agreement top speed 250kmh or 155mph vehicle like Model S and BMW 5-series need around 160kW of constant power. Vehicles with more drag need more - less drag need less. So some Teslas car reach gentlemen top speed agreement speed. At least for a short period as RWD model rotor will overheat. AWD should be able continue for longer.

Motor RPM can be calculated as we know reduction gear ratios and tire diameters.

 

[jkn]

Hi! I've been looking for proper full-load curves for Tesla Model S and I've found that at the speed of 40 mph (approximately 64 km/h) car almost gains full power. This looks pretty strange to me, because speed continues to rise. As I know, there is no gearbox on Model S and the ratio in the gear unit is constant. So, why do we see increase of speed as the power and torque go down? As I see it, you can only do it by changing electric motor rpm. So, how does Tesla changes them? Do we have any curves (like rpm/power/torque) that describe it?View attachment 220188

From 0 to 40 mph acceleration is limited by traction, so car cannot use full power. Above 40 mph acceleration is limited by available power. Above 73 mph (M SP above) acceleration is limited by available torque and power goes down. When power is low enough car cannot accelerate more.

Motor RPM is almost 30* frequency of 3 phase AC into motor. (Almost, because there is some slip.)

 

[arnis]

Actually from 0-40mph it is not just the traction. People have used super sticky tires.
Even though Tesla is magnificent, it is not limitless. There is a maximum torque value set to protect drivetrain.
And also maximum amps battery can support. And also maximum amps inverter can invert.

AFAIK OEM tires are near the maximum grip they need to have for maximum acceleration.
With supersticky ones acceleration gets only marginally better from 0-30.

 

[mariusciclistu]

teslasp600nm_webinfo
Hello. I think that if you study the above simulation you will understand that torque is everything and as long as the resulting traction force is bigger than the air friction forcez the car will continue to accelerate. Power is just dust in our eyes. Ignore it.

 

[mariusciclistu]

teslasp600nm_webinfo
Hello. I think that if you study the above simulation you will understand that torque is everything and as long as the resulting traction force is bigger than the air friction forcez the car will continue to accelerate. Power is just dust in our eyes. Ignore it.

teslasp600nm_webinfo Sorry. This is the autoloading url in english.