Generator or Inverter?

okrobie wrote:
Thank you all for straightening that out for me.

I know that "Quality" Generators have low THD (Total Harmonic Distortion) The ones with low THD can run sensitive electronics and have a prettier shaped sine wave output.

Is there a way to determine the THD of a generator before you buy it. I haven't seen the THD listed in the specs of most generators.

Is it safe to run a refrigerator on a plain old contractor grade generator?

Thanks for your help.

Regards, Jim

Jim,

THD is a term used in the audio (HiFi) industry. what you really care about is the Decible(DB) level. Often you will see the DB rating of a generator. portable non-inverter style generators are generally very inexpensive, and very noisy. The newer inverter style generators are relatively quiet and are available up to about 3500 watts.

I believe all traditional (fixed speed) generators deliver exactly the same kind of power your house has (assuming they are tuned right).
But I don't think anybody will like contractor-grade generator run next to RV.
As already explained, inverter generators use DC alternators and then inverter converts it to 120V AC. Depends on the electronics in inverter the sine can be cleaner more or less.
The advantage of inverter generators is that they can deliver high power when needed for AC start, but once the amps are not needed they lower the speed to actual use, lowering the noise and fuel consumption.
The most popular Honda generators also do have advanced mufflers what makes them extremely quiet. I have Generac inverter generator that is not that quiet, but still beats older (pretty loud) RV Generacs and I like the fuel savings.
My older 4000W Generac was using honest 1 gall of gasoline per hr.
Honda EU3000 will ran 5 hr on the same fuel and load.

Thank you all for straightening that out for me.

I know that "Quality" Generators have low THD (Total Harmonic Distortion) The ones with low THD can run sensitive electronics and have a prettier shaped sine wave output.

Is there a way to determine the THD of a generator before you buy it. I haven't seen the THD listed in the specs of most generators.

Is it safe to run a refrigerator on a plain old contractor grade generator?

Thanks for your help.

Regards, Jim

The presence of a 12v output has nothing to do with it.
If someone honestly doesn't know if they're selling an inverter gen. or not then they're likely not.
I'm not aware of any inverter gen. larger than about 3,000 watts except Honda and Yamaha. Most inverter generators tend to look all "closed up"; that is, they have side panels and look a lot like a box. The regular type generators are often referred to as open frame. They have a frame with the components mounted to them with lots of room in between where you can "see thru" the machine.
Your best bet is to simply get the model number and look it up online. Any seller that can't give you the model number is not someone I would deal with.

The main function of a generator is to generate power, usually 120vac. Some of them also generate 12vdc to charge a battery.

Inverters change the power, usually, in the RV world, change 12vdc to 120vac. Inverters do not make (generate) power, just change the voltage.

okrobie wrote:
I'm shopping the "used" market (Craigslist) for a generator or inverter. I'm finding that often, sellers don't know what they have. And, more often I don't know how to distinguish between an inverter and a generator.

For example I looked at a 4KW Briggs & Stratton which had a DC output connector 12V 10 Amp. Does the presence of DC output prove that it is an inverter type?

Thanks, Jim

are you talking about an inverter generator?
or just an inverter?:h

there are inverters, that aren't generators
there are regular NOISY generators
and there are QUIET inverter generators

I think you are trying to distinguish between a conventional generator and an inverter generator. A conventional gen is a single speed engine that drives a mechanical style generator. An inverter generator is a variable speed engine that drives an alternator which then has an electronic package that "inverts" the DC output of the alternator to AC.

Many conventional gens as the B&S you talk about also have a small DC output to charge external batteries. They are not "inverter generators".

I would expect anyone who has an "inverter generator" to know it(they cost a lot more); if they don't know you can assume they have a conventional gen.

Doug