Guy, could you clarify or expound on your statement, "For example, the 7500W capacity of our modified Honda EU6500is Inverter Generator can........" The Honda technical specifications state that the EU6500is is rated for full load (6500w) for 30 minutes or less, 5500w continuously. What modifications to the engine/generator/inverter have you made to produce the additional 1000w, without burning out the windings?
We are not just providing an additional 1000W, but 2000 more watts because the 7500 Watt load we put on our modified Honda EU6500is is a continuous load. How we modify the generator is proprietary information. What I can say is that our Transformer/Distro is able to provide 7500 Watts in a single 60A circuit because the capacity is already built into the machine by Honda. In order to understand how it is possible to get 7500W of continuous power in a single 120V circuit out of a Honda EU6500is generator, one must first appreciate three things about the continuous load ratings given for generators.
First, the factors generator manufacturers use to derive load ratings include not only the mechanical components (engine & alternator), and the electrical components (circuitry & wiring), but also the market for which it is intended (how it will be used) and the brand image of the manufacturer (life expectancy of the product.) A quick survey of the wide range of continuous load ratings (5000W-7000W) of generators, by manufacturers other than Honda, using the same Honda GX390 engine as the EU6500is supports this fact. Second, when Honda engineered the EU6500is it was not only for the North American market. Like a car, Honda engineered a base model for the world market that they then customize for the different national markets. The difference between the various national models is primarily in the power output panel, which is configured according to the electrical system and prevailing standards used in the national market in which the generator will be used. The 120V power output panel on the North American EU6500is is under-rated for the actual generating capacity of the machine. Finally, the continuous load rating of generators is what you can reasonably expect to get at the business end of the power panel allowing for all the vagaries associated with the load put on the generator. That is, the same engine and generator components will carry different continuous load ratings depending on its' intended use or the type of load (resistive, inductive, capacitive) that will be put on it. I would like to explain each of these in more detail.
When you compare how Honda outfits the base model of the EU6500is generator for the European and UK markets, where the standard circuit for domestic power is 230/240 Volts and 13 and 16 Amps, to how Honda outfits the same generator for the North American Market, where the standard circuit is 120 Volts and 15 or 20 Amps, one realizes that the continuous power rating of 5500w for the North American Model of the generator is under-rated. Where England and Ireland have not entirely conformed to the European Union Standard of 230 Volts, but still generate 240V power, Honda has engineered the base model to support a version of this generator for the UK market (the EU65i) with two 240V/16A circuits (3840 Watts/circuit). To support the UK market, the base model must be designed to generate at least 7680 Watts (2x3840W/circuit = 7680W). It is beyond the scope of this post to go into more details (those interested should contact me off list for a detailed side by side analysis of the wiring schematics of the two generators) but simple math (16A x 240V = 3840 W/circuit x 2 circuits = 7680 Watts) clearly demonstrates that it the base model must be designed to generate at least 7680 Watts.
To empirically test how much generating capacity the base model is capable of, we tapped an EU6500is in a similar fashion to the UK model, the EU65is, and used a step-down transformer to convert the 240 Volt output to a single 120 Volt circuit. We then used the generator's overload sensor to empirically test its' capacity with a load bank following the parameters as set forth in the manual:
"If the generator is overloaded, or if the inverter is overheated, the red overload indicator will go ON. When an electric motor is started, the red overload indicator may come on. This is normal if the red overload indicator goes off after about five seconds. When the generator is operating overloaded, the red overload indicator will stay ON and, after about five seconds, current . will shut offî
What we discovered about our modified EU6500is was startling. We found that we could power a continuous load (more than 30 minutes) of up to 7650 Watts without the overload indicator coming on. When we exceeded 7650 Watts, the red indicator blinked intermittently. When we exceeded 7800 Watts the red indicator came on continuously and power was cut off to the receptacles. Since, according to the Honda Manuel it is normal for the overload indicator to come on for short front-end loads, like electric motors starting, our results suggest that the continuous load capacity of the base model, or the EU6500is after our modification, is actually 7650 watts. And, when you consider that electric motors require up to three times more power to start than is required to keep them running, it suggests that the peak rating is actually well above 7650W.
Suspecting that it was not just coincidental that the actual continuous load capacity of 7650 Watts is the equivalent of two standard household circuits in the UK, we confirmed with Honda Motors USA that in fact the base model of the EU6500is generator is engineered to generate the equivalent of two UK circuits and has a continuous load capacity of 7650Watts. And, that when Honda configures the base model for the North American market with 120V circuits, it is not fully utilizing the power generating capacity they have built into the machine for the worldwide market. Since I am out of space, I will have to explain the second reason it is possible to run a continuous 7500W load on our modified EU6500is in my next post.
Guy Holt, Gaffer, [url="http://www.screenlightandgrip.com""] ScreenLight & Grip [/url], Boston