Load Inertia - Starting Frequency Characteristics
These characteristics show the change in starting frequency due to load inertia.
The stepper motor’s rotor itself and the load have inertia, which causes delays and advances in the motor shaft during instantaneous starting and stopping. This value varies depending on the pulse speed, but if it exceeds a certain value, the motor will not be able to follow the pulse speed and will go out of step (misstep).
The pulse speed just before the system goes out of step is called the starting frequency.
The variation of the maximum starting frequency with respect to the load inertia can be approximated by the following formula.
\(\begin{align}f=\frac{f_S}{\sqrt{1+\frac{J_L}{J_O}}}\ [\mathrm{Hz}]\end{align}\)
- fS
- Maximum starting frequency of motor alone [HZ]
- f
- Maximum starting frequency with load inertia [HZ]
- JO
- Rotor Inertia [kg·m2]
- JL
- Load Inertia [kg·m2]