Motor-

Speed-

Torque-

Power-

Efficiency-

-- fps

stator rotating field

rotor magnet field

A B C coil current

Drag: orbit · Wheel / pinch: zoom · Slow motion keeps the pole count and the slip honest, only the clock is stretched

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EV Motor Lab: Torque–Speed Curve, Field Weakening and Permanent-Magnet vs Induction

A generic traction motor in the dq frame. Push the speed up and watch the operating point leave the current circle's torque plateau and squeeze through the shrinking voltage ellipse.

Drive and motor

DC bus voltage400 V

Current limit (peak)500 A

Motor speed1500 rpm

Torque request100 %

Optimal control: MTPA + field weakening (off: i_d = 0 only)

Stories (presets)

Live readout

copperironinverterfriction/windage

Current plane (i_d, i_q)

Torque and power vs speed

Green: constant-torque region. Blue: constant-power region (field weakening). Grey: past the knee. Dashed line: analytic base speed.

Efficiency map

Vehicle: gear ratio and 0–100 km/h

Gear ratio9.0

Vehicle mass1800 kg

The drawing shows a fixed 18:54 and 17:51 spur pair (9.0:1); the slider changes the maths and the road-speed readouts, the picture keeps its 9:1 teeth so the gears still mesh.

Experiments: simulation vs analytic

A. Base speed (where the voltage ellipse first touches the peak-torque point)

B. How flat is the power above base speed?

View, animation and quality

Animation speed1.0x

The science

Made with 🟠 Blender · Three.js