Hey Ken! Thanks. Yep that spec (dated 6 October 1959) says: 4.1.1 A-c power. The a-c power system shall be a 3-phase, 4-wire “Y” system, having a nominal volta

Hey Ken! Thanks. Yep that spec (dated 6 October 1959) says: 4.1.1 A-c power. The a-c power system shall be a 3-phase, 4-wire “Y” system, having a nominal voltage of 115/200 and a nominal frequency of 400 cps. The neutral point of the source of power is connected to ground (see 3.2), and the ground is considered the fourth conductor. and 5.1.5 Steady-state frequency. The a-c power systems frequency shall be maintained at 400 ± 20 cps for steady-state operation.