I am unsure if the onan 5500 or 7500 LP models have the internal windings on the stator/communtator to generate a 120/240 V. By specifications from cummins/onan it is 120V only and that is all I have to go on.
In order to get 240V you have to double and have separate windings on the commutator.
This is why the RV 30 Amp plug comes into play. Most home generators have a 30 Amp twist lock connection. The 30 home vs RV are differrent so you can not screw it up. RV 30 is single leg of 30/120V. Home is 4 wire 30 Amp/leg 240V between both legs or 120V each leg to Neutral.
With that being said. The RV generators only run at 1800 rpm. To increase the windings and spacing for a 240 circuit and maintain a compact space. The generator would have to operate at 3600 rpm. Double what the RV gen set operates and much louder. Go to a nascar race and you can do the comparison and contrast for noise. Most tracks limit the operational hours for generators just for this reason.
You can get the 240V at 1800 rpm by increasing the size of the # winding's which results in a larger physical size or 1/2 the current rating / leg for the same physical size.
If there is a service outlet, normal duplex outlet at the gen set which only supplies 120V then it is on the same leg anyway and the splitter you mention is redundant. Where this device comes in handy is if you are connected to the 30 plug @ at a campground and need more power. Because they are separate in the CG circuit breaker box but you can not tell if they were wired to the same leg or not.
So you could still fry your electronics if miss wired unless you just use an extension cord from that duplex outlet. Safe or sorry. I would not go that route.
In my unit. The 50 only supplies the Washer Dryer closet and if I had a second AC Unit. I've only used it for convenience or to plug in a space heater in the bed shower area into electrical socket closet because I have the the not equiped W/D.
If you have 2 honda's with a parallel kit and connect via the 30Amp plug it still is only 33 Amps @ max load.
Air conditioner soft start units. The original ones were nothing more than a larger capacitor to supply surge current upon start up. Newer ones may use a charge pump / limited current boost, circuit to perform the same or similar function.
They have been around for at least 30 yrs and we have used them on difficult problematic ac unit compressors. Wiring is pretty straight forward if you are comfortable with this type of work. Amazon has them also, otherwise if not online. Then it is off to an electrical distributor FYI: may require a license for purchase.
https://www.google.com/search?q=soft...w=1622&bih=854
I just checked this is a home depot item now. Maybe be order only or on the shelves.
http://www.homedepot.com/p/SUPCO-120...SPP6/203566183
Chris