How does an inertia type rolling road work?
The majority of rolling roads used to determine power figures in the US are inertia dynamometers. Inertia dynos do not directly measure the force on the dyno rollers to determine power figures. Instead, these systems calculate the force on the rollers using the formula: F = ma Where F is force; m is mass; a is acceleration The mass and system inertia of the dyno rollers is known. In order to calculate the force applied, inertia dynos measure acceleration of the rollers by measuring the increase in current and voltage production when the dyno’s eddy-current retarders are used as a power generator instead of a power absorber (as used to hold the dyno load when mapping engines). Force on the rollers is therefore the roller mass multiplied by the acceleration determined by the voltage output. This force is multiplied by the radius of the roller itself to give torque at the wheels using the following equation: T = Fr Where T is torque; F is force; r is radius of application Power is determi
