Found this for sale ( with cooler, $ 500 ) , owner has no other info other than it has supposedly been converted from 440 to 220. The 3 pole breaker in the top right corner looks like it is a 3 phase unit.
The Hobart site does not list this welder in the manual section.
Edit, found some info, on on E bay, looks like a DC only machine
Hobart Bros. Porta-Tig Welding Power Source.
specs: rating: 3 phas-1phase,
duty cycle: 60%,
amps: 21.5 A-1PH, 20 A-3 Phase,
spec # 409483-2
Where to Buy
Service & Support