You are right about that, each magnent has a north and a south pole, the best example for me to explain it to you, is for instanse, on a two mags motor on one magnet's north faces the can and south faces the other's north face, I know you've got to know this! it all depends on how they are cut and glued to the can. you could have two exact looking mags and one has its north facing one direction and the other north on the other magnet faces the other way, so the armature is right in between the magnetic field, right in between north and south.