Tr1 and Tr2 more or less the same, Tr3 half of them.
TR1,TR2 and TR3 provide a continuous output load of 75 Amps (normal)with forced cooling or 50 amps with convective cooling.
Does the GND PWR setting on the Electric Panel have an Amp rating or not?
The overhead panel only displays DC voltage and output frequency for the Ground power,same for Stby power and inverter.