440v 3-phase TO 220v single-phase welder

Dick there are two diff kinds of 3-phase, one w/ central com and one without. The one with a com should give ya 3 x 220 v . However, 50 amp is quite a load and so you should first check with your Cap

https://www.belden.com/blog/data-centers/3-phase-power-wye-it-matters

So Tric, what'd he say

don't take my word as you would a professional, from what I understand a three phase is Black Red Blue meaning circuit/breaker 1 is blck, 2 is red, 3 is blue, 4 is blck….., so each color or number is a single phase hence three phase. high voltage which 440 is considered if I remember correct is Brown Orange Yellow. so in theory you would have to hit one color twice to use that same phase. You cant technically do this since your double pole breaker could be one piece it would have to be separated by the following two phase breakers.

I read that you could run a distribution panel off of one phase and from there put a double pole50 a breaker
they make 3 phase step down transformers