Hughes Autoformer 50 AMP Regulator/PT50-C

[bncinwv]

The Autoformer does provide some protection, but not much if you compare the joule ratings of the two units. We use the autoformer to boost low park voltage since we have stayed at some older parks with power supply problems. The Autoformer will let us use the rig in those circumstances. The EMS serves a completely different purpose, it is for protection of the higher end electronics in the rig at low voltage conditions that the autoformer cannot correct, overvoltage conditions, spikes, etc. It may be overkill, but as an engineer I wanted to be sure I had as many bases covered as possible and feel that I have done that. In my book the EMS (or at a minimum a surge guard type device) is mandatory and the autoformer is an added luxury because of specific circumstances that we have experienced. It may well be overkill, but I justified it in my mind and most important of all had DW's blessing!! Others may have different reasons.
Bingo
On edit: My understanding of the the Hughes autoformer is that it does not "turn off" at 118 volts, rather it lowers it's "boost" to 2% instead of the 10% "boost", it supplies at lower voltages. If the voltage at the feed is 128 volts, it will still provide a 2% boost and this added "boost" will cause the EMS to shut off power to the rig. I have experienced this at some high voltage connections and have to take the Autoformer out of the feed loop to the rig (I installed mine to be removable for this situation as well as if it fails I can still have power to the rig). As a disclaimer, my use of the word "boost" is to keep from having to go into the Ohm's law end of things (for those who will chime in with electrical specifics) that are really not necessary for most peoples' knowledge and application.