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Friday, June 24, 2011

Induction Generator Load Test

Original Article

As promised on the no-load vid of this induction generator, here is a video of the first load test. I have both a 120 volt and 220 volt connection; the 120 is powering the light bulb (which is 100 watts; these will soon be outlawed so stock up) and the 220 is powering a heating element from an oven. As you can see and hear, the single belt and lack of a belt tensioner is the limiting factor. When I switch on the heating element, the voltage drops to 160 or so, with a corresponding dimming of the light bulb. But when I shove the 2x4 in there to tension the belt, the bulb brightens again and the high voltage rises to about 210 volts. At this voltage, the current into the heating element is about 7 amps, which equates to a bit under 1500 watts. Add the 100 watt light bulb and you get almost 1600 watts, with no sign of any problems.
I ran this setup with both loads connected for about 20 minutes. The water was boiling, but that's ok. I didn't want to run it any longer without a larger cooling hopper, though.
One thing I neglected to check during filming was the frequency. I remembered to check it after I had put the camera away but while the generator was still running, and I found that it was only 54 Hertz. So I increased the speed of the engine, reaching 58 cycles and 218 volts under load into the heating element. Because I was checking the frequency with the same meter I had been using to monitor the amps, I didn't get a current reading at that voltage. But it was definitely increasing its power output, because I could not reach 60 cycles. When I increased the speed beyond the 58 cycle setting, the single belt reached its limit and started slipping even though I had pounded a short chunk of 4x4 between the motor and generator so it would hold tension.
So why am I out here messing with this thing in 100 degree weather (literally. I was gonna say something like it wasn't really that hot, it was only 98 degrees; then I went and looked at the thermometer to get an accurate reading, and it is 102 degrees outside)?
Because the electricity was off when I was shooting this. It was off when I woke up this morning, then it came back on for about an hour, then went back off again. Typical day here. So I really need to put this engine on the 7.5 KW generator that is sitting beside it, because I need a generator that can run the air conditioner, refrigerator, deep freeze and all that stuff, and the engine that is currently (no pun intended) on the generator needs a rebuild. So I needed to get this experiment out of the way to free up that engine. Don't worry though; I am sufficiently pleased with the outcome of this test to want to do some further testing and use it for some practical applications as well; just with a different engine. I have a little 6.5 hp Kubota diesel engine that is not currently employed...