It's unlikely that you will get an answer here, as we mostly talk about vintage domestic machines. Be aware that industrial machines do all kinds of things and are often single purpose machines. What I mean by that is they may be a machine made specifically for hemming pants, putting in zippers or making curtains, etc.
I personally wouldn't consider buying an industrial machine unless you are somewhat familiar with them. Parts may be hard to find as well as finding a repairman.
The place I would ask is on
VSS. They may have some information or know where to go for information.
bk