A very large old spot welder. Water cooled, pneumatic plunger, controlled weld timing. 400V AC supply, which means it runs the single phase weld transformer across 2 phases of 3 phase 415V.
Another restoration project. Surprisingly it actually contains some electronics. 'Solid State' they proudly boast, which gives an idea of the vintage.
It's home now, but I still have to get it off the trailer. Plan involves a large improvised timber tripod and a chain hoist. Tomorrow.
The thing is immensely heavy. I don't even know if my 1000Kg chain hoist will be adequate. Might have to buy a bigger one.