inertia match √(Jload/Jmotor) fastest move at move time there
load accelerationhow quickly the move finishes (higher is quicker)Through a ratio N, the motor's torque grows N times at the load but its own inertia grows N² times. So acceleration rises with N, peaks where the motor's reflected inertia equals the load's (N = √(J_load/J_motor)), then falls. Top speed at the load is the motor's top speed ÷ N. Fastest-move ratio is where both limits balance, and it's usually below the inertia match.