Generator from a gas engine?

[biac]

generator

I am just starting,I hope to have some pics of the hardware I have now,but after reading on this board,i think i want to use some type of pic chip for the controller.

I have no idea where to start,any good reading i should start from? i want to use a servo from a R/C car/aircraft for thottle control.

 

[DigiTan]

Okay, thanks guys. Yes I rechecked the rating, which is 1/8 not 8 HP. (Didn't seem plausable to get thousands of watts from it really). So then it looks like my best bet is to maybe a pushmower or go-cart engine then? Is it likely for a salvage yard to have one? I don't exactly know how things work there.

 

[Dean Huster]

DigiTan, most of the Briggs & Stratton electric-start engines made in the U.S. have two "generator" windings: one for the charging circuit, a simple arrangement of a rectifier in series with the battery and a second winding for the lights, which is why most of the riding mower lights only work with the engine running. The original International Harvester Cub Cadet made in the 1960s used a 7hp Kohler engine with a standard Delco DC generator, regulator and battery for a standard 12-volt system like a car and the lights ran right from the battery while the generator charged the battery. The generator was then used in reverse as the starter motor.

I owned a model of that Cub Cadet and used it with a York automotive air conditioning compressor. With the built-in clutch, pressure switch and pressure storage tank, it made a wonderful compressor and I could easily develop 165 psi withe the thing. Trouble with using the auto compressors is that the lubricating oil that is normally maintained withing the Freon system is suddenly open to the world and if you don't watch it, you'll soon be throwing a rod. Been there and done that!

I don't particularly like most 2-cycle engines. Most don't come in larger horsepower, all are dirtier on the environment than 4-cycle engines and they need the gas/oil mix which is a pain. They're well-suited to their original uses on chain saws, line trimmers and leaf blowers where you need small size and weight. In the U.S., they're starting to mandate the elimination of the 2-cycle engines because of the emissions problem and we're starting to see 4-cycle weed trimmers on the market. It also seems to me that 2-cycles engines are harder to muffle and quiet down than their 4-cycle cousins.

Dean

 

[B-o-b]

induction motor Generator

Ok-- If I'm not mistaken, I'm assuming that yer wanting an AC power source/generator using a gasoline motor to drive it with; this can be done. I havent yet made 1, but it's cetainly do-able. From what I've gathered so far, this is how it's done:

Using induction motors as generators is a very cost effective way of providing a generator. The induction motor, is driven at 50 RPM over its rated speed and the motor becomes a generator. Induction generators are much less expensive than other types of generators, but require some kind of excitation to operate. It is possible to utilize induction motors as generators in stand alone applications, utilizing the residual magnetism in the windings, as well connecting capacitors to supply continual excitation.

Once, there was a really nice web page that explained how to make 1 using a lawn mower engine and an AC motor, but sad to say, that site is no longer with us. However, I grabbed the schematic of how it's made and have attached it here... Hope this helps.

Bob

 

[DigiTan]

Thanks guys. Those last posts really clear up a lot of things there. So far, I haven't really decided on AC or DC yet. DC sounds nice for now, but I have a few safety conserns about that may sway the project. I'll check for all these components and hopefully try to estimate what kind of power I can expect here.

Anyway, this week I'm in the process of trying to locate the 1-8HP engine. From the sound of the thread so far, my best options are lawn mowers and go-carts; then I should only try weed-eater engines if I'm absolutely desparate. I'm having some trouble figuring out where to get this stuff. My only certainty is that I don't want to buy anything new (cost). Beside garage sales, does anyone recommend other places to look? Salvage yards maybe?

 

[williB]

people round here throw lawnmowers out all the time..
other than that a salvage yard is probably your best bet ..
find one where you can just walk in , and look around..

 

[DigiTan]

Alright, that sounds like a winner to me. So exactly how do these places work? I just cart it off and haggle over the price I'm guessing. I'm mostly trying not to get myself ripped off here. And should I take any tools with me?

 

[williB]

every place is a little different , the one by me was great , they would have piles, huge piles! of "stuff".. it was amazing really..they would have everything from pumps to pistons, industrial stuff to household stuff,like lawnmowers..i saw another one today that someone threw out ,a really nice one , but i dont have the room to store anything like a lawnmower in..

Abridged version..yes bring tools ..
you bring the engine up to the office plop it on the counter , and say ' How much?' if it is more than you wanted to spend , say ' thats a little steep'
or ' thats more than i wanted to spend '.. nobody is gonna force you to buy it.. right..? its just like anything else..
put on work clothes , you are gonna get dirty..and ' When in Rome'

 

[DigiTan]

Well here's something weird.

I went to Fleet Maintanance of Texas today and they told me it is usually cheaper to get a brand-new mower than just a mower engine. The engine in the showroom was $300, while an equivalent mower would be closer to $100. :? Looks like I'll be sticking to garage sells and salvage yards then.

 

[Oznog]

I so dig Honda's inverter generator (several others out there). Since the freq is fixed by the inverter, not tied to generator rpm, it can throttle down to the quietest and most fuel efficient RPM that won't stall the engine.

Plus it's just a remarkably small and quiet 4-stroke to begin with. Got a little exhaust muffler, intake muffler, and even the plastic housing is part of its noise attenuation.

I only wish it had a starter, because I would love to be able to start and stop it remotely. I had ideas of building it into a compartment too. They make a bigger one with electric start but it's much more expensive.

I wondered if the generator could be powered externally and turned as a motor. I assume it's a permanent magnet motor so that's not too unreasonable. I wish I could afford a second one to take apart.

 

[DigiTan]

So about how much efficency should I expect from a generator/alternator? I've heard people suggest it might be as low 50%. Is a reasonable guess?

 

[tinkerbean]

if its engines your looking for, well.....i have had times when i wish i had a motor with just the right specifications that i needed and couldnt find a one....other times i have had far too many lawn mower engines and weed whacker engines then could find a place for.

people just give there old crap to me because they know i can tinker with it till it either works the way its intended to, or gets the 'mad scientist' treatment and transforms into something completly different.

i too have been thinking about a SMALL portable generator, something like a weed whacker engine that turns an automotive alternator - i live in hurricane country down here in NC and i also have a pet snake that requires a heat lamp and 80 degreese as much as possible...but if the electric goes out for 3 or 4 days - i need to think of something else (letting the snake die is not an option).

if your search gets to the point where you run into some money and your tired of fixing junk..

www.northentool.com

they sell new gas engines of just about every kind and they also sell generator heads...kinda pricy but you dont have to wait for the awesome parts to just fall in your lap.

.....ironically, i just put a new(rebuilt) alternator in my truck and traded the old one in for a lousy $5 core......kickin myself for THAT one because i have a 2 cycle leaf blower and an inverter - (hopefully that would run the snake heat lamp for quite some time) also i wouldnt mind having a 12volt neg ground portable power source for running a CB radio in case the hurricanes get REAL bad.

 

[tcmtech]

Your only about 5 years late on being helpful.

As long as they dont freeze reptiles can live just fine without heat and many can even freeze without problems too.

 

[tinkerbean]

heh, not goin to lie, did a google search about weed whacker engine generators....


guess i need to pay attention to the date posted......sorry bout that


also, thanks, im new to this snake game - this awesome pet kinda fell into my lap and im still learning