Generators come in 3 flavors.
Contractor's models. Open frame, Noisy but you can easily get 3500 or 4500 (3600 is 30 amps) however I've seen the power out displayed on a 'scope and some of them can be................. Scary These the engine usually runs at 3600 RPM
RV type (Onan or Genrac) also whole house fixed generators.. Not really designed to be portasble but the RV types are "installed" Not nearly as noisy either to the ear or to the electronics. Much cleaner output Generally the enginre runs at 3600/N (1200 or 1800)
Inverter: Very quiet, Very efficient fuel wise, VERY VERY Clean.. BUT
Generally the model number is the PEAK power. BUT you can parallel them A Pair of Honda EU-2000i, in parallel (or one regular and one companion, they make two models) can provide a solid 30 amps.. A 3,000 can not.
Makes: I cited only Onan, Generac and Honda but there are others in all categories, At one time some of the "Knockoff" Inverter models had some serious issues with regulation but far as I know they have addressed most of them and today they all compete. HONDA has the best service network should you need service. YAHAMA is #2, others you may have issues indi9ng service if needed. (in the inverter class) ONAN and GENERAC also have good service networks.
Finally some generic stufr.. Generator Exhaust can kill you, Make sure the Generator is not blowing exhaust into the RV or house,
Generators like to run.. A new generator (portable) OTHER THAN THE INVERTER types you may want to run a tank o gas tyhrough it with only a resistive load (lights or heaters) before hooking electronics to it (Story ollows) Inverter modelds this "Break in" is not needed.
:Run the Generator 1/2 Hour under at least 1/2 load (heaters work well) every month.
The story
I own a Generac 1000, Traditional generator, ullyu enclosded, grew legs and walked o (Got stolen) but when I first powered it up an APC UPS complained, Both Frequency and voltage were good (per a meter) dso the only thing left weas waveform.
After the first tank of gas.. APC was happy.. Some electronics need to be "Conditioned" and the half hour a month does that.
Finally a word about HONDA inverter models.. They have a genuine FUEL PUMP (Most are gravity feed) so they can suck gas out of an eternal tank.. Called an Extended Run Tank.