Inertia ratio
The inertia ratio describes the relationship between a mass and its inertia. While the mass provides information about the weight of a body, the mass inertia (J) provides additional information about the geometry. For drive systems, it is important that a certain ration between load mass inertia and rotor mass inertia of the motor is not exceeded. This mass inertia ratio is referred to as lambda (λ).
The following table shows typical inertia ratio limit values.
Application | Inertia ratio |
|---|---|
High-end servo drives for maximum accuracy with maximum dynamics | λ ~ 1 |
Typical servo drives in machine tools | 1 < λ ≤ 3 |
Handling systems with high dynamics | 3 < λ ≤ 10 |
Direct drives with rigid coupling between motor and load, simple applications without specific demands in terms of positioning accuracy and dynamics | 10 < λ |