This attachment takes 50% of the automaton's current HP and gives the automaton a 30 sec refresh. Each tick of 3 seconds gives 10% of the converted HP as MP. Only works with Stormwaker body (Harlequin body has the HP/MP of a PLD, Stormwaker the HP/MP of a RDM)
So at 800HP, it does a 400HP convert, which gives 40MP back each 3 seconds for 30 seconds. Usually the automaton uses some of this MP to cast a Cure IV, or the PUP uses Repair with Automaton Oil +1 (20HP regen for 400HP total)