Generator caveat emptor

[Kurtsara]

Originally Posted by HISSSSS

Yep, just about every group has their own MLAs (Multiple Letter Acronyms) to keep typing down to a minimum and this inadvertently also acts as a confusion factor for those that haven't learned what they mean. You can always use a web site that provides acronym lists to get up to speed, most of the time: S&B and DW didn't pop up on the ones I tried so eventually I figured out what they are to the RV forums.

To me it’s just people getting lazy, like I always see prolly instead of probably

[followingsea]

Originally Posted by followingsea

...
So could I get 1200 watts? ....

The first risk damaging my old $100 HF genny. .... Of course buyers should beware when they are paying a premium price.

Ran a test last time I was boondocking. The most I could get with the engine is 1000 watts.

Earlier in the year found a deal on a Powerhouse 2100/2200W rated inverter generator that I could not pass up. Based on customer reviews I should have been able to run a 15k BTU A/C.

Tested it beside son's house in Las Vegas and the 4.35hp / 125cc engine could start and run the A/C.

The limiting factor when I boondock is propane because that is what the Onan in my MH runs on. with a few gallons of gas I can extend my stay until my black tank is full.

No longer worried about damaging the HF generator, I replaced the overload protection with a higher rating and and adjusted the speed regulator until the engine could produce no more power. After the test I finished using the gallon of gas with no apparent damage to the HF cheapy.

The bottom line is that a generator can only produce as much power as the engine delivers.

[cavie]

Originally Posted by followingsea

Ran a test last time I was boondocking. The most I could get with the engine is 1000 watts.

Earlier in the year found a deal on a Powerhouse 2100/2200W rated inverter generator that I could not pass up. Based on customer reviews I should have been able to run a 15k BTU A/C.

Tested it beside son's house in Las Vegas and the 4.35hp / 125cc engine could start and run the A/C.

The limiting factor when I boondock is propane because that is what the Onan in my MH runs on. with a few gallons of gas I can extend my stay until my black tank is full.

No longer worried about damaging the HF generator, I replaced the overload protection with a higher rating and and adjusted the speed regulator until the engine could produce no more power. After the test I finished using the gallon of gas with no apparent damage to the HF cheapy.

The bottom line is that a generator can only produce as much power as the engine delivers.

The generator has 2 basic parts. The generatotor and the motor. The generator can produce no more power the the generator section is designed to produce. Not limited by the motor.

[followingsea]

Originally Posted by cavie

The generator has 2 basic parts. The generatotor and the motor. The generator can produce no more power the the generator section is designed to produce. Not limited by the motor.

You are not correct. My test showed that. Since you are a 'master electrician' I can understand your confusion.

A generator is turned by a mechanical device device such as a internal combustion engine or a steam turbine. Good design practice is too design generators, turbines, and nuclear reactors to exceed nameplate specification.

My first job after being a navy nuke was as a test engineer for GE. If GE turbines, generators, or reactors limited power productions, then lawyers got involved.

Later when the power plant demonstrated contractual performance, companies would sell services to 'uprate' rated power.

When it comes to small generators for RVs, the buyer should be skeptical of claims made by sellers.

My $88 generator purchased at Harbor Freight produced rated power. I measured it. Power produced was limited by the overload device.

When I saw the same generator advertised as a 1200 watt generator at a higher price, I was skeptical.

I replaced the overload device with one that would limit it to 1200 watts. By manually adjusting the speed I was able to get 200 more watts or a 1000 watts.

It is reasonable to assume that the generator can be rated for 1200 watts because it can supply the corresponding current without damaging the generator. However, if the engine is under sized it will not produce rated power.

Bottom line, when looking to buy a generator make sure the engine is not underpowered for the electrical rating.

[Goodspike]

Originally Posted by cavie

The generator has 2 basic parts. The generatotor and the motor. The generator can produce no more power the the generator section is designed to produce. Not limited by the motor.

It's limited by both, which is why a generator running on propane generally produces fewer watts. They typically balance the power of the motor on gas with the generator electronics. But the engine produces less power on propane, so it puts out fewer watts.

You could attach a 455 V8 to drive the electrical generator of a 2,000 watt generator and it would still only produce 2,000 watts (but because that engine is so powerful it would do so even on propane!)

[followingsea]

Originally Posted by Goodspike

It's limited by both, which is why a generator running on propane generally produces fewer watts. .....

Yes and no. I think you intended to say my Onan generator RATED for 7000 watts is derated to 6500 when fuel by propane.

My generator produces the same number of watts when the A/C is running because load determines watts produced not fuel source.

The size and weight of a portable generator is important because it is most likely the limiting factor if you want to load a generator.

For me I need to be able to lift it and put it in a storage compartment.

One of the misconceptions about about motors and generators is how much current they can draw or produce. I have seen a control system failure with concurrent multiple overload protection failures. The inspection found no damage.

[Goodspike]

Originally Posted by followingsea

Yes and no. I think you intended to say my Onan generator RATED for 7000 watts is derated to 6500 when fuel by propane.

My generator produces the same number of watts when the A/C is running because load determines watts produced not fuel source.

The size and weight of a portable generator is important because it is most likely the limiting factor if you want to load a generator.

Well I didn't know the specifics of your generator, but yes that's the sort of difference I was getting at.

But of course a generator only produces what the demand requires--but that's up to its limits. I don't see how that's relevant to the discussion. But if you want to add that in sure.