3000W Chinese Gensets Info.

crackshot wrote:
You are right. My mistake for not reading manual correctly.
I did get a twist lock last night and did run the A/C no problem.
When the compressor kicked in, there was a load where it revved up the engine for a couple seconds.
Now what my manual says is that I have 4 110v household outlets.
One of the outlets is 1800 watts 15 amps. The other outlet is 2800 watts 20 amp.
So I should be able to run my A/C from the outlet that puts out the 20 amps and not need the twist lock adapter since the twist lock outlet specs the same.

Oh-my-gosh, not another one of those beasts! :S I thought they were all extinct by now. :h

Several years back another well know Chinese genny builder did the same thing. A few of us "old timers" on this thread questioned the wisdom of putting a 20 amp breaker on one winding and a 15 on the second. Soon thereafter it was discontinued.

The problems with one winding potentially loaded more than the other at 120 volts were asking for a fried winding dinner along with a significant amount of harmonic distortion appearing on the output waveform. The manufacturers were "assuming" that this design pattern would only be used for 240 VAC operation and both windings would NEVER be loaded to the max at the same time when drawing 120 VAC. Obviously, they did not know much about the RV crowd. Our group needs 240 about as often as often as a flat tire. What we needed was a 120 volt genset that could provide a balanced load across both 180 degree opposed output windings. Such an animal would give less so called “dirty power” than a center tapped 240 volt arrangement and maintain the total wattage generated at 240 volts while directing it to a single 120 VAC outlet.

It did not take long for the design of most gennys coming from China to comply with a RV’ers needs along with the ability to select series or parallel from a front panel switch and direct power to a single 30 Amp TT outlet.

BTW – the major difference in a L14-20 and a L14-30 twist lock outlet is the design of the locks. Just raising the physical maximum current rating on the outlet does not mean the genny will put out that much power – but I will have to admit it does look more powerful with a 30 amp rated outlet than a 20 amp rated outlet. You know, sort of like the implication of putting a coffee can size exhaust tip on a little 4 cylinder foreign car.

Now to the wattage thing.... (remember, wattage is a measure of power and thus work that can be done). 15 amps worth of electron flow (breaker limited) will produce a maximum of 1,800 watts at 120 volts of pressure. If we increase the current limitation to 20 amps, the maximum wattage will increase to 2,400 watts. Unless the "new math" has returned, this is a difference of 600 watts, not the 1,000 watts you reference. If that is indeed what your manual states, the Chinese are much worse at math than I originally suspected.

Anyway……. Those ratings are the MAXIMUM for extremely short periods of time. Operation at those loads for sustained periods will cause a rapid rise in alternator core temperature that will soon let all the smoke out of your generator head. As we all know, the magic ingredient of smoke cannot be put back into the windings and a new genny will soon be needed. Additionally, we have not even discussed how much of this energy is wasted as heat in the conductors that make up the alternator and related wiring while voltage drop increases due to heat induced resistance changes from a higher electron flow.

Regardless of what the big numbers say on the box, ads or manual, you have a 2,800 watt generator capable of providing a combined total of 23 amps of reliable current over an extended period of time at 120 volts without major concern of damage to the generator. In short, the box it cam in LIES!

As an old E.E. and college professor who has spent much of my life closely associated with the miracles of electricity and electronics along with the clear understanding of our inability to neither create nor destroy energy (only change forms) I have come to believe you will never get more power out of a gasoline engine driven generator than you put into it - unless it is momentarily assisted by a bolt of lightning.

Put the mythology books away and believe what Mr. Watt and Mr. Ohm have written.

If your desire is to run a 13,500 to 15,000 BTU recreational vehicle air conditioner with one of these 3,000 watt class Chinese generators you need to have parallel alternator windings rather than series – even if one of the series windings might manage to get it started.

But, I guess if Joe’s uncle’s brother’s cousin knows someone that says otherwise then the Wizard and I must be all wet with our constant admonishments to their professed wisdom.

Make it parallel or you will be confronted with a series of problems. (Pun intended)