Building a series hybrid generator

Here (http://www.autopartswarehouse.com/d...QQNSAQQAlternatorQQ20002004QQUSALT-1805A.html) is the kind of thing I'd be looking at. I'd go grab one from an junked truck in a pick-n-pull actually.

130A x 14V or so --> ~2000W. I'd expect that at higher voltages the current wouldn't drop as fast as the voltage, just like the current rating of a wire doesn't depend on the voltage. So maybe at 140V we could still get 50A out --> ~7000W. Almost 10 HP, just the range I'm looking for. Throw a 15 HP small engine on and you're there. The torque on the shaft and the load on the bearings would need to be considered.

I'm not sure how fast it would need to spin. I'd want to figure out the most efficient speed for the engine and the alternator and just use pulleys. I'm not sure how much power you can put across a serpentine belt. Might need larger pulleys on the engine and the alternator to get enough contact area and low enough tension on the belt.

I understand that it is trivial to hook up two or more alternators in parallel and control all of the field currents coils together. Then it would just be adding as many alternators as needed. Better cooling then.

You are correct, wire size cares more about amperage than voltage, and the wire insulation cares about voltage and temperature. Keep in mind how automotive people rate things, unless they specify a period of time or say "continuous" you have to assume they rated it in peak power. How long would the alternator produce 130A before cooking something? The web site did not give a weight but I think it is less weight than a 2KW generator head which is also rated in peak unless specified. Based on mass alone I don't think 130A continuous would be true.

You can increase field current to raise output to higher voltage but you would need to know the max current allowed for the field. With higher voltage you might be able to squeeze some extra watts out of it.

Parallel is no problem, you would use diode rectifiers on the outputs which would block outputs from interfering with other outputs. Adjust fields individually to match outputs. If you start to string a lot of them together you would want to look at a single larger generator. For a single alternator see if you could couple the engine shaft to the alternator. Engine speed may not be compatible with this but that is where the research on alternator RPM vs. power out comes in.

iss407 said:

Anyone have any ideas?

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I have a couple,

Look in http://www.surpluscenter.com They usually have lots of engines and generators.

Your talking about building your own, I've seen it done and the major problem with them is they are all NOISY and they VIBRATE. And when you are done, well . . . they are home built. Don't get me wrong I have lots of home built stuff. But sitting in a car for a number of hours listening to a generator run.

I think the best alternative is to shop for a used RV genset. Onan is one good one. They are silent, compact and well insulated for vibration. they are desigbed for remote starting. Many hav 220 volt taps. 3,000, 5000 to 10,000 watts are not uncommon. Voltage is clean and stable. There are diesel ones as well. They are made to fit into a confined space and just run and run (quitely). They are current and common so parts are available. Every time I've looked on ebay I have seen one or two.

I know that you can scrounge and shop and make up something cheap, but then you have a cheap generator

Just my thoughts.

Jim

CPLTECH said:

Here are some gen heads:
http://www.northerntool.com/webapp/wcs/stores/servlet/category_6970_36+182379

$350 - $690

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I bought a 5.5KW gen head. It has two 100W 15amp outlets with a 220W - 20Amp three prong twist plug. I says it is for belt drive however it is a keyed 3/4" shaft that mates perfectly with the 3/4" shaft of the 20 HP D&D systems motor I have for it. I am going to use it as a temporary energy supply for our well when we lose power (Which can occur a lot up where we live!) to power our well pump. I will be running it off 6 - 6V 229amp batteries for the battery pack along with an Alltrax AXE controller etc. and an Optima Yellowtop D31A for the contactor coil. I can use my initial 72VDC charger to charge the pack when it is not in use. Like I said it is only for emergency water so it is not a long term power station.
I got it for about (US$)580.
Am seriously thinking about the 10KW head... My idea is this: a hybrid pack. Take one nice sized engine of like 22HP (a Kohler horizontal also available at Northern...) the 10KW... and a nice sized AC motor... of about the 18hp size (40 peak)... I imagine if you have to pay for gas, you could effectively, with the right configuration of controller, contactor, etc., get a vast reduction in waste and perhaps get an equivalence of say 60-70 miles per gallon or more with a small car using a standard transmission/transaxle... or if you were to try something like an older Toyota or Mitsubishi van... use a 310VDC battery pack as well for alternate power with this system... at least this is the theory at the present time... I'm a-schemin'
P.S. the use of the gas engine could be very easily effected by using ones imagination and having some sheetmetal skills... think out of the box!