DavecUK A DC motor will draw whatever wattage it needs to, only limited by the resistance of the windings (which isn’t that high). It’s why the main control board in the Niche such (as it is) has a a self resetting cut out, if too much current is drawn in too short a time (protecting the motor windings). So it really doesn’t make any sense to talk about maximum motor power consumption in W.
I agree with all of the above, and understand the design. But this design begs the question of why a cut out would be necessary if a motor is spec’ed that’s powerful enough to grind coffee beans to espresso sizes with a given burr size.
And just to address the issue of different burrs of the same size requiring different amounts of power, burr geometry may play a role in how much power is needed for a given burr, but the burr size itself is probably the major factor. In addition, the number of third-party burrs is a pretty well known quantity, and basic engineering for this issue would probably include something like “The most power hungry burr in this size needs X watts, so let’s spec a motor that’s X+15% watts”, or something like that.
I’ll mention again that every other grinder manufacturer I can find seems to have no problem giving some sort of idea of how powerful the motor is. It’s sort of like MPG for cars – your actual mileage will differ from the stated MG depending on your driving habits, but the MPG ratings allow some sort of comparison between one car and another.