/diy/ - Do It Yourself

im fixing some industrial equipment. the problem is the switch controlling a motor doesnt work when switch is placed to position "3".
i found pic related regarding the switch (T0-6-158). im well beyond retarded when it comes to ac, three-phase motors and have no fucking clue what im looking at. i managed to decipher the table with crosses (if i understand correctly, this shows which contacts are energized in which position), but ive got no fucking clue what "0-(B)delta-(A)Y-(B)-YY" is supposed to mean. i understand that these are different ac motor configurations, what why are there 5 of them? the switch has 4 unique positions. why second to last is simply (B) without configuration?