Evals / Motor sim
LEGO motor spinning a gear — live DC-motor model
A Powered Up medium motor (part 21980) drives an 8t pinion meshing a 24t gear (3:1 reduction). The spin is computed each frame from a first-order DC motor model — torque-speed line + rotor dynamics — not a looped animation: drop the voltage and it slows, load the brake past stall torque and it stops.
Controls
Telemetry
0 rpm
motor speed
0 rpm
output speed (÷3)
0.0 N·cm
torque at 24t
off
state
Torque-speed line (operating point)
The red dot is the motor's live operating point sliding on τ(ω) = τ_stall·(V/9) − (τ_stall/ω_nl)·ω. This same curve becomes the joint-actuator model in the physics bridge (gate G3).