Well, since we've been without power going on the sixth day now, I have had plenty of time to really get to know my generating capacity. Like many of you guys, my mind never, ever stops turning and yes I have laid awake in bed listen to a twenty HP Onan suck down $2.75/gal 87 Octane at the average rate of 1gal/hour which equates to roughly $75/day to run SSS's mini power grid.
So... I was thinking.......
Here's my idea and and you tech guys (and Miller Engineers...please) chime in and let me know what you think. My idea is for vastly improving the fuel effeciency of an engine drive when used in an AC generation setting. It involves marrying three established technologies into one unit. To begin with, basic prime mover power rotating magnetic field AC generation is a very established and mature technology. It has been around for roughly a century now. The problem is that in the case of my Bobcat and any other traditional gen set is that it has to sit there and run at 3600RPM (or 1800, depending on the unit, but a set RPM nonetheless) to provide standard 60 Cycle (or Hertz...don't want to take credit away, now do we!) power. This is the case whether I need 100 watts or all 10K. On the other end of the spectrum is the little Honda EU2000 inverter style gen set that I also use. It litterally sips fuel. This is because it has a variable idle on a small engine that turns a DC alternator. This power is then sent through an inverter to produce the 60 cycle power. The beauty of this design is that because the DC alternator can run at a varible RPM and still produce it's power (higher RPM equates higher amperage, but the voltage can be maintained at any reasonable speed). The little inverter has two throttle settings. One for full power and one for demand varied auto idle. The biggest draw back to the auto idle is it's lacking ability to handle inductive load starts. As we all know, inductive loads basically look like a dead short to a supply when the are energized and then taper off as the load comes up to speed, hence the term "motor starting capacity". So my idea is to take those two ideas and put them in a compactor along with my UPS from the computers and hopfully this is what will come out:
Take the DC/CV ability of an engine drive and couple that with a 10KW inverter, but.....between the two put either a very large capacitor bank (think of a filter bank on an AC to DC regulated power supply that filters the post rectifier bridge, pulsating DC to usuable straight DC) or a small battery bank that would handle the brief spike in current so that the throttle could compensate and take up the load. This way you have the efficency and cleanliness of the inverter coupled with the effiecency of a variable RPM DC generator. Of course the mechnical governor would be best replaced with an electronic one, but that technology is readily available. That would give the ability to run the prime mover at the RPM just enough to produce the power being consumed.
Ok, that's my idea
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Thread: New Generator Design
12-15-2007, 09:26 AM #1
New Generator Design
Last edited by SkidSteerSteve; 12-15-2007 at 09:33 AM.Bobcat 250, MM 210, Syncrowave 180, Spectrum 375
Cat 242B Skid Steer, Challenger (Cat/Agco) MT275
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