Workers pose in front of revolving field for GE generator at Boulder Dam. Wound revolving field (with lifting beam suspended from 2 cranes in place) for 1 of 2 General Electric vertical alternating-current generators, 82,500 KVA, 180 RPM, 16,500 Volts, 60 Cycles, Type ATI-W, 40-pole (Unit no. 5) side view, in hydroelectric power station at Boulder Dam, for U.S. Department of Interior Bureau of Reclamation.