Hi,
I don't understand why you would need two adapters for the Hughes.
I use an autoformer partly because my RV is 30 amp. I always check polarity and voltage under load before I plug in my unit.
I do have an inverter/charger that does load support--but that doesn't mean it does voltage support.
There are autoformers from Mexico that can support 50 amp. I have the Sola Basic (4000 VA) which both boosts and bucks voltage.
The Hughes folks do have a 50 amp autoformer, which supports both legs of a 50 amp RV. To use it with 30 amp shore power, a 30 amp to 50 amp dogbone adapter would be needed. This would be a good item to own.
The reason for having an ems, on 50 amp, is the risk of having an open neutral. That can present up to 240 volts on one leg, causing damaged to most of the 120 volt devices on that leg. The EMS would disconnect, or prevent current flowing when plugging in.
Or, alternately it would be quite possible to have 140 volts on one leg, and just 100 volts on the other. If an air conditioner were run on the 100 volt leg, it may be permanently damaged, what's even worse, is, the damage can 'sneak up' on you, as the damage is cumulative.
Get a top of the line EMS from Progressive Industries.
There is much lower risk with a 30 amp RV and I have superior surge repression on the RV. I do most often run with the Sola Basic autoformer as low voltage damages a lot more RV's than high voltage.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.
