Most often they have a larger pump that feeds water several of these pivots. Then each pivot has a long run of underground that comes from the pumps electrical panel. I ran across one that was over 1,500 ft away. As far as how many amps they draw depends on how long the pivot it. Each set of wheels has an electric motor. A farmer once told me how many horsepower each motor was but I forgot. I think they are like 1/3hp or something. They can’t really draw too much because that 1,500 ft run was a #4 copper stranded. So max is 85 amps per leg of the 3 phase.