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252034913 6Be89A71B8
Anne writes – “Here’s a home-made generator, using an old lawn mower engine and alternator… Being a practical fellow, he built a generator for himself with items lying about the house. This is the whole thing. It features an old lawn-mower engine, alternator (fitted inside base), storage space for string lights etc, and an operator panel. The base is made of MDF, treated with oil to make it somewhat weather proof. “Link.


  • obm

    I wouldn’t like to be near that thing, as it will be emitting RF radiation even more than a vacuum cleaner.

    For those who don’t know, vacuum cleaners are the strongest source of RF radiation in a house, considerably more than a cell phone or TV set.

    Where is my Al hat?

  • gear_head

    Did the authour reduce the ‘at load’ speed of the engine I wonder? Seems to me that an engine like that would run a bit fast for this application. I’d be interested to know what the petrol consumption is for this generator as I’d be quite interested in making one myself.

  • nap70

    Having seem the flickr archive of the finish product, I feel ready to put one of these together myself. Thanks, make!

  • wsuverkropp

    - To gear_head: To the best of my knowledge, there’s no tinkering with the engine. Most lawn mower type engines are governor controlled at 1750rpm or so, with a few running at 3000 rpm (or so). That’s well within the range of a normal car engine running. And like in a normal car, the pulley on the engine is a little bigger than on the generator.
    Fuel consumption is unknown. This thing is not quiet (think of it: it’s a lawnmower!), so I have no intention of running it under full load for an hour to find out. It does work, however.

    – To obm:
    As the construction suggests, this unit was not built for elegance, but rather it’s a good example of using available materials to solve a ‘problem’. Having said that, the installation is no different from that in a car. The little engine generates electrical noise of course, but nothing excessive.
    The alternator is from a car…and most cars generate some RF noise, but nothing excessive either (otherwise, your car radio or cellphone would not work).

    Vacuum cleaner motors can spark like crazy, which indicates the brushes need to be replaced. A bit of maintenance goes a long way.

  • Pekar

    http://theepicenter.com/tow082099.html
    here are some directions.

  • JaneQPublic

    So what? Line the box with aluminum foil (or metal screen) to make a Faraday cage, and ground it. No more RF, for maybe a dollar expense.

    My concerns are over different issues. For one thing, the output of a typical lawnmower engine is MASSIVE overkill for turning an alternator. I think one would be better off using a fractional-horsepower engine, from a weed-whacker for example, rather than a 2.5 to 5.0 or so horsepower engine from a lawnmower.

    As for noise, better mufflers — even tuned mufflers — are not usually that difficult to build.

  • JaneQPublic

    Line the inside with foil or screen and ground it. No more RF! For about a dollar.

    However, this is overkill — inefficient — for driving an alternator. Rather than a multiple-horspower engine, I would use a fractional-horsepower engine, like for an edger or weed-wacker.

    Mufflers — even tuned mufflers — are not that difficult to build. In a pinch, route the exhaust through a wooden labyrinth lined (but not filled) with fiberglass insulation, glass side in.

  • KHG1000

    I made one out of a 3.5HP motor. With my 2000W inverter the motor isn’t strong enough to keep up with it. I used a 4 hp motor and seemed to be maxed out with the refrig plugged into the inverter. I was looking to use a 6.5 HP motor and 2 alternators in tandum. Have not aquired a 6-8 HP motor to test yet.
    khg1000

  • carbon740

    why is everyone always gotta be a hypocrit. I think what you did was quite impressive. I look forward to building my own. As to put my two cents in. When I get a chance to build one, which my idea is similar to yours. I would like to look for an engine that will give me ample feul efficiency, And I also thought about multiple alternaters.

  • P.

    If you would go and read the instructions from the site that Pekar posted, then you would see that you can use a 2.5 horse engine with a 2000 watt inverter, by changing the “gear ration” via different sized pulleys. Hope this help.

  • imon_fire

    I just started making one like this but im going to use a toro 2 stroke 4hp engine instead of a 4 stroke engine.I think it will give me more rpm and more power.

  • imon_fire

    I just started making one like this but im going to use a toro 2 stroke 4hp engine instead of a 4 stroke engine.I think it will give me more rpm and more power but i dont know just yet.

  • dsae

    hgh

  • Jarod

    According to Balmar, a high end alternator manufacturer, an alternator will use about one horsepower per 25 amps of output. To determine wattage output, Watts = Amps x Volts
    Thus, 2000 watts will require 166 amp minimum in theory.

    I would recommend a 200 amp alternator or multiple alternators. A minimum 8hp engine, 10 to give extra headroom would be advisable. An additional benefit is a deep cycle battery which can act as a buffer allowing higher outputs for short periods of time.

    Happy building!

  • Loren

    someone give me directions on how to make this

    http://www.myspace.com/omfg_tator_tots

  • Richard

    Efficiency wasn’t the issue. The issue was saving by using existing materials that were just lying around doing nothing. With that said, great ideas guys!

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