Anyone know if thats an arc welder or large battery charger on the right?
I don't "know" but here's my opinion. The coiled wire and plug on the large cabinet on the right look too small to be a welder. Arc welders back then had big, thick wires and a heavy plug like you see on an electric stove or clothes dryer. Usually, arc welders had controls and output cable connections on the front face of the cabinet.
So I'm thinking the large cabinet on the right is a battery charger. It has a newer, compact charger sitting on top.