Hello I have a miller matic 252 its a 230 460 575 machine i got it from a guy at work who had it in a shop its set up for 460 and has a 30 a 480 v plug 3 phase I wana change plug to a 3 prong for 220 in my garage I see it has a jumper but what steps do I need to take to switch this over any help greatly appreciate of