I am looking to power up my mill but discovered it has a bigger motor in it than it is supposed to have. The mill is supposed to have a 15 hp motor but instead has a 20 hp. My dilema is that there is a 30 horse phase converter for sale that is a third of the new listed price. I have been told that the phase converter needs to be twice the size of the main motor on the mill, so it would have to be 40 hp phase to start the oversized 20 hp on the mill. Is that accurate advice or do you think i could get by with the 30 hp phase converter?