Mel Knight wrote:
....

What's the "effective" difference in function of a dual-voltage grinder
if it's set up at 115 versus 220? Anything meaningful?
....
Only meaningful difference is that the supply current is halved as said.
Makes supply voltage drop/losses smaller and avoids potential for
circuit overload/trip on smaller (15A) circuits.

Other than that, the difference is inconsequential.

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