Dual Generators (not dual fuel, but two generators)

irollman wrote:
BearAK,
Slight thread-drift, I'm thinking this may also be how they get electricity from multiple windmills in a windmill farm? That's something that always bothered me too. Along with, how the heck do they "switch the grid" and maintain phase polarity? But I digress, and that's a discussion waaaaay beyond this one

Yes, also Solar installations, including home solar installs. They send DC to a device (inverter) that has the ability to sync up before it puts out.. and once it's connected assorted things keep it in sync.

I'm not fully up on everything that is going on but during startup it basically senses if there is power and "locks to the phase" how it stays there. I do not know.. But then I've not fully researched it.

Linked (synchronous) generators. Which is a string of paralleled AC generators, need to have individual unit load sharing control devices. A generator lagging in speed will be "dragged" up to 60 Hz by the other generating devices. VARS calculation is needed so windmill farms are computer controlled. Voltage, amperage and Hz alarm and shutdown.

The Pacific Intertie System operting on 500,000 DIRECT CURRENT volts is a three thousand two hundred MEGAwatt transmission line: It's architecture is fascinating.

The point being, the same principle used in th tiniest inverter generator is the same as a DC intertie line. Keep reading :)

The grounding system ("chassis negative") consists of 1,067 cast iron anodes buried in a two-foot trench of petroleum coke, which behaves as an electrode, arranged in a ring of 3,255 m (2.02 mi) circumference at Rice Flats (near Rice, Oregon), which is 10.6 km (6.6 mi) SSE of Celilo. It is connected to the converter station by two aerial 644 mm2 ACSR (aluminum conductor, steel reinforced) conductors, which end at a "dead-end" tower.

Fascinating: Yes/No

From the EU2000i shop manual:



- - -
I work for Honda, but the preceding is my opinion alone.
Robert@Honda

I have run the Honda EU3000 and paired EU2000s.
My strong preference is for the pair of 2000s. They make more power, if fitted with a simple portable outboard boat motor gas tank they run longer than a 3000, and you only ever have to lift 50 pounds.
If you need help making up your mind, go to your local dealer and try to lift an EU2000. Then try to lift an EU3000. Decision made!!
Plus the twins give you the option of running just one when that's all you need, or using them elsewhere for other things.
The 3000 weighs 140 pounds.

If cost is a factor, which I figure into everything it seems, two Honda 2000s are cheaper than one 3000. Add the extended run gas caps and a 6 gallon portable marine gas tank, and it is still cheaper if you shop around. I didn't shop very much either. The advantage to running one 2000 as opposed to one 1000 is the coffee maker. Or the toaster. Or the microwave. All of these are handled by one 2000, but the Dometic microwave will prove to be all it can handle.
As far as fuel consumption, according to the Honda dealer I bought my first 2000 from, the 2000 is actually cheaper to run at comparable watts, say 500. That is half a load to the 1000, but loafing for the 2000.

If I want to run my AC, I hook up my parallel cable, start the first 2000, then start the second 2000. I then turn off the eco idle on both and power up the A/C. After it has run for a little while, I turn on the eco idle, and they idle down as needed, and easily start the compressor when it needs to start. I have tried a few different times, and one of my Honda 2000s will not run my A/C, but the two of them handle it easily. I do leave my A/C fan on continuously, so that may help, but I like the white noise.

TheBearAK wrote:

The reason to run AC anywhere is because you can transmit the power with lower losses. High voltage and lower amps = smaller wires.

I left that unsaid in my earlier post so as not to confuse things. After all, if we're running a generator and DC, it's only short distances. Even longer distances, like for low voltage yard lights, are OK.

This is the reason why Westinghouse won the argument over Edison.

I don't want to hi-jack the thread, but Wind generators depend on the type of generator at the top. Some are DC right out, but the big ones are AC.

From what I understand, there are two basic methods to phase them. One is to convert to DC and run through a large inverter, and the other is to have the alternator speed controlled and separated from the propeller speeds. Much like a CV transmission. The props can be spinning fast, but all they do is produce more torque. The alternator stays a constant speed. The second method is cheaper to do, but requires more maintenance.

Almost all of the smaller home ones are alternators (AC) and get converted to DC to charge batteries. Then batteries feed an inverter.


The reason to run AC anywhere is because you can transmit the power with lower losses. High voltage and lower amps = smaller wires.

BearAK,

Yours is one of the more "engineer-like" explanations that I've seen, as well as wa8xym's. This appeals to the engineer in me, and makes sense. Now I understand how they do this.

Slight thread-drift, I'm thinking this may also be how they get electricity from multiple windmills in a windmill farm? That's something that always bothered me too. Along with, how the heck do they "switch the grid" and maintain phase polarity? But I digress, and that's a discussion waaaaay beyond this one.

I'll be sharing this thread with the GF's parents and will give them my opinions as appropriate. One of the wiser opinions here is to get them out using their RV, that way they'll figure out firsthand how it's used and what they'll need, just like we-all have. What's right for me may not be for them.

Funny thing about these inverter generators, the signal coming out of the power source is AC, it then gets converted to DC, then back to AC.

Why? This way you can run the generator at any RPM. The AC coming out is variable in the frequency, typically fairly high. Often the same speed as the RPM. (i.e., 900 RPM = 900 Hz).

They convert that to a DC signal, and then back to a AC through the inverter. Inverter puts out a steady 50/60hz signal. often a modified square wave.

Anyway, if it were me and I planned on camping a lot, I'd probably get two, but I'd get the 3000watt and then get a smaller one, like a 1000 (or 2000). Run the smaller one when you don't need AC. It can charge the batteries and run all the lights just fine. It is smaller, easier to handle and can last up to 14 hours on a tank of gas. Run the 3000 watt only when you need AC or run the Microwave.

Hassling with a Y cable and having two generators running just seems like too much.

We too often judge others by our experience.
We camp mostly in California Sierras, where at 4000' elevation we never need AC.
Even in San Francisco -East Bay area as of now (end of June) the nights are in 50's so our house gets cooled down at night and doesn't need AC when 90's in the afternoon hit.
But few years ago I did travel with my truck into Phoenix.
It was about 110F and base on my CA experience I planed to sleep in truck cabin.
It did cool down at 10 PM to 98F.
I had a choice of running engine with AC overnight, but calculated the fuel at the time at over $3/gal and hotel come cheaper.
Rare occurrence in other states, but happen.
So calculate generator running time into you decision.
Would suck to get up every 2 hr to refuel.