For some applications there are indeed 2 grounds, a neutral ground and
a machine ground. There is some reason the phase may be out if not
wired correctly (no im not an electrician) It is the difference
between 3 and 4 wire 220. Same voltage with different configuration...

Do yourself a favor, check with a professional or your local township
for codes...110 can kill you, but 220 likely WILL kill you if wired
wrong...