Any motor experts here who could explain how carbon sleeving allows higher power to be held to higher rpm?
I don't think the sleeve itself did it...
To touch on the first post,
I thought peak power happens on a P100D around 45 MPH, and that it was limited to battery output.
There is a maximum power the pack can supply; however, the power the motor can put out rolls off at higher speed due to back EMF (voltage) proportional to RPM which reduces the effective voltage across the motor windings which reduces the current in the motor which reduces power.
Two ways to shift the roll off point: one is to boost the pack voltage, this is unlikely to maintain supercharger compatibility (you can divide the pack in half and switch from parallel to series, but that adds complexity). The other is to change the RPM versus voltage ratio by altering the motor windings or construction.
Decreasing the windings proportionally decreases the back EMF but it also reduces the torque you get for a fixed amount of current. However, at low speeds, the drive electronics are limiting torque anyway, so no biggie.
At least, those are the normal ways...
Tesla did something a little different, Plaid is tri-motor, so the rear drive unit went from one motor to two. That means each motor only needs to put out half the power, meaning half the torque for a given RPM. Less torque is less current and needs less voltage across the motor meaning the point where back-EMF limits power shifts upward by a bunch. At the same time, the low end max torque output is cut in half per motor, so you can rewind the motor with say half the windings, and keep the same drive electronics. This winding change also halves the back-EMF pushing the power reduction region even higher. Net result: no motor induced power roll off within the operating range.
Or something like that
The carbon part may be for strength due to shinking the rotors to fit two in the samish volume. Less diameter means less torque for the same current, so they may have boosted the max RPM to compensate. Or maybe mass reduction.