Here’s the deal on inverter generators...
On a regular generator, the frequency (60hz) is determined by the RPM of the engine. That RPM is either 1800 RPM for a 4 pole generator, or 3600 RPM for a 2 pole generator.
This speed must be maintained regardless of the load, and those speeds are not necessarily the speeds that give you the most fuel economy.
An inverter generator usually has a three phase AC alternator (similar to the one in your car or truck) which is rectified to produce a high DC voltage. This DC voltage feeds an inverter (like the ones you can by at Harbor Freight) and the inverter synthesizes the 60 HZ sine wave on the output.
This not only frees the engine to run at a speed that matches the horsepower to the load, but it also fixes power factor issues you have with generators.
The article doesn’t mention this, but some of the most expensive generators are inverter generators, but also some of the cheapest ones are inverter generators.
All of the (cheap) small, light 2 stroke generators are inverter generators. This is because 2 stroke engines are terribly inefficient at 3600 RPM.
Just curious - I had always thought the store-bought inverters produced ‘AC’ that was more square wave and less-so smooth sine wave.
referencing your remark “the inverter synthesizes the 60 HZ sine wave on the output”
Be nice if they did produce smooth sine wave. I don’t know; what say you?
Thanks for that information.