max_p0wer t1_j1i5pps wrote
Internal combustion engine horsepower numbers a little bit misleading. The numbers they tell you are actually "peak" horsepower. A 2022 Corvette makes peak 490 horsepower at 6,450rpm. This means it makes less horsepower at every other rpm, most notoriously at low rpm's.
An electric motor makes its peak power ALL the time.
Red_AtNight t1_j1igtfx wrote
Not exactly. In a rotating engine, power is engine torque multiplied by rotations per minute. Electric motors don’t produce peak power at all engine speeds, because in order to do that, they’d have to produce peak torque at 1 rpm and then have the amount of torque produced gradually decrease as the engine speeds up.
What electric motors do is produce consistent torque at all engine speeds. They still have a power curve, it just looks a bit different than an ICE.
With an ICE, you only get peak torque at a certain engine speed, and you actually get less torque when the engine is going too fast.
max_p0wer t1_j1itpka wrote
Do a google search for Tesla dyno graphs. You’ll see the power is virtually flat while the torque decreases steadily. It’s constant power output, not constant torque.
A1phaBetaGamma t1_j1je8vl wrote
I think the person you're replying to is thinking of DC motors
Cheben t1_j1igtpj wrote
They have basically constant torque (up to a point), but not power. Power output grow with rotational speed (power is torque times speed) , so the rated HP for electric vehicles can be extracted just before the torque drops of. A ICE also has low torque at low speeds, which is why they feel more sluggish to drive.
Electric peak power is at about 2900RPM there
max_p0wer t1_j1ish12 wrote
Any “constant torque” would be due to the fact that at low speeds you’re traction limited so only a fraction of the cars power can be used.
Once you’re no longer traction limited, the torque will steadily decrease and power output will be flat.
This is a Tesla S P85D on a dyno. Notice the torque peaks (at 864 ft-lb!!!!) then steadily decreases. The power is nearly perfectly level just above 400hp for the entire second half of the run.
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