EMS is a TLA with a double meaning.
Energy Management Systems by Intelletec are called EMS, these are load shedders. if you have this system you have a 50 amp RV and on your control panel (House controls) is a display that shows AMPS when you are plugged into 30 amps WITH AN Adapter.. it will be dark on 50 amps.
Energy Monitor Systems by Progressive Industries are also called Surge Guards and protect your RV against low/high voltage/frequency and other things.
HOw to tell.
Turn one A/C to fan.. or plug a trouble light into any outlet and hang it where you can see it as you plug into the park power.
Turn off park breaker and plug in
Turn ON park breaker.. Does light or fan come on RIGHT NOW. or is there like a 15 second (or longer) delay
NO Delay = NO EMS of the PI type.
PI's HW-30/50 c EMS units have eithe ra 15 second or nearly 3 minute (I'd choose the longer) delay between TURN on of the breaker and delivery of power. Same for TRC's only the longer time is differnt by a few seconds.
WHY this is important.. Two reasons (And why I choose the longer setting).
For 3 years I was stuck in one spot due to mechnicial issues.. During that time we had several power fails.. Some were days long some hours long, some one second long.
IN all cases when the power is restored there is a short period were every Air Conditioner in the park (And sometimes beyond) is trying to start. .I do not even want to think about the voltage dips and surges while this is happening.. My box is going 1-2-3~~~~~170-171-172 CLUNK power
By the time it gets to CLUNK, power is stable.
The second, for the one second "Blinks" my A/C is running, pressure built up in the cooling lines. now the Compressor is going to re-start with a full head of pressure (Stalled rotor conditoin over heat, damage, tripped thermal breaker (self resetting) may take 2 or 3 tries before it starts)
NO, 1-2-3~~~~170-171-172.. The Pressure will bleed off and by the time CLUNK power on happens the compressor is re-starting with balanced lines just like it is designed to do. NO damage, No overheat, And I'm happy.