[MikeGM]

Thank you very much for the detailed responses.

I think I will take your advice regarding the targeted accelerations and axis speeds, as well as designing using the rated torque. I will also take a look at the TinyG, thanks for the tip.
I have been looking into the rotor inertia figures of various motors that appear to be suitable for my application and the figures vary wildly. I have, for example, downloaded a catalogue for leadshine ac servos (no idea of prices) which publishes the inertia figures of the motors in the "[kgm2*10-4]" units. here is a screenshot of some of the figures:



I note the 1.8kw model reports 30.15 kgm2*10-4. Figures for a 750w model from the same manufacturer indicated only 1.56 kgm2*10-4.

On the DMM site the 1.8kw model is advertised as "23.8kg-cm^2" and the 750w model is advertised as "2.45kg-cm^2" almost a factor of 10 difference. I think you may have placed the decimal point in the wrong place in your conversion; should it not have been 23.8 x 10^-4 kgm^2? I have 1cm^2 as equal to 0.0001m^2 - and scientific notation as 1 x 10^-4 m^2, unless I have missed something.

If I input the figures for the aforementioned 1.8kw leadshine or the DMM into the calculation you did for me earlier in the thread, would the motor inertia not then become by far the largest component of inertia in the system?

Am I missing something?

Kind regards,

Mike