Well, this is a motorhome thread and I don't have one.
The way I understand AC power generators (NOT A EXPERT!), there are two ways of governing (controlling the speed) in order for the output to remain at 60 cycles per second and it depends on the type of inverter you have.
A solid state inverter can take varying cyclic input (rpm of the alternator) and still output 60 hertz. These generators are easily identified by the "ECON" setting which allows the ROM to ramp up and down depending on load. They are very fuel efficient in ECON, but are slow to react to rapid demands on current (like an Air Conditioner starting up). If you are going to run an AC off these generators, the manual recommends "NORMAL."
A "contractor" type conventional generator that uses a rotating (mechanical) inverter and they MUST run at a constant 3600 RPMs regardless of load in order to produce 60 cycle AC. As load increases, the RPMs start to slow down, (like a lawn mower getting into tall grass) and the mechanical governor increases fuel to keep the RPMs constant.
This must be the type of generator you have.
Conventional vs. Inverter Portable Generators - Cabin Life Magazine
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW