... 2.Coupled with Stamford,Marathon alternator Gas Generator SetLand use,prime output :20-250kw Specifications:1) Output range: ... optional 8) 230 / 400V AC, 50Hz / 60Hz, 0.8pF three-phase and four wires alternating current output9) Frequency: <3% 10) Frequency ... and over current b) Operation display: i) Unit voltage, tri-phase load current and frequency display ii) Water temperature, oil pressure ...