A towed agricultural machine includes a converter, configured to convert a first voltage potential generated by a generator to a second voltage potential. The second voltage potential powers a component of the towed agricultural machine. Further, the towed agricultural machine also includes a switch that senses the absence of the second voltage potential from the converter and switches to powering the subcomponent with a second voltage potential received from a source external to the towed agricultural machine. The second voltage potential output by the converter can also be combined, on a power bus, with the second voltage potential from the external source or another source.