To carry this a little farther, all three of the units have been hybridized in various ways. In other words each one has unique features, such that you can't be sure when comparing wiring on one unit, that markings and terminations will be the same or even close to the same on similar systems on the other units. SP5103 and I worked on the HEP on one of the units to replace the voltage regulator. It was an after market replacement, not the actual Newage part, so again it took some sorting out. Once the new part was in place, we were ready for the smoke test when the air starter failed for the HEP unit. Sorry not something you can run to NAPA for. Oh, we hadn't mentioned air starters on all engines and HEP units? Not too many track side air compressors in remote canyon country. Maybe this is the case with all RDC's, but the air compressors for the brake systems and starting the engines are powered by electric motors ran off the HEP generator. You would think that the HEP engines would at least have conventional electric starters, otherwise an airless RDC ain't going anywhere. SP5103, how many different electrical voltages did we count on one of these? 480V 3 phase, 120/240 1 phase if I recall correctly, 64Volt DC and 12Volt DC as well. I was privileged to work with my two friends on these units a few times, and can say I am not a fan of the RDC. As they were originally constructed with parts still serviced by the original manufactures,they were probably a terrific idea.