Lynn Coffelt wrote:

Actually, most (maybe all) DC, conventionally commutated motors have
brushes wide enough, and commutator segment spacing narrow enough that that
they work, as some say, "make before break". Otherwise,
there would be many rotor positions where the motor would not start. (we all
have experienced that with burned commutators, no?)

Good point. I think the earliest of the DC motors were electrically
noisy, to the point that early stereos had trouble. Doing it the way you
say would reduce the RFI.