yep, just over heated and shut off they do..
especially if you use a long extension cord....they shut off for a minute.
I have the lincoln 125 weld pack, been using it for a year and a half with no issues once I bought a 6 gauge extension cord from harbor freight, thing works really good for what it is.
I can't see buying any lincoln or miller below the Lincoln 125 unit, unless all you ever weld up is wheel barrows.