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OT - Adjusting Voltage on a Small Generator

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  • OT - Adjusting Voltage on a Small Generator

    I just purchased a little 800 watt, 2-stroke generator:




    http://www.harborfreight.com/800-rat...tor-66619.html


    The frequency holds well at 59-60hz, both loaded and unloaded, and I believe the freq can easily be altered by adjusting the rpm. The problem is that I am getting about 112 volt unloaded and 107 loaded.

    Is there anything I can reasonably do to improve this?
    I won’t be running any electronic devices from this generator, but how close does the voltage have to be before I will start causing problems with, say, a refrigerator?

    I have run it for a couple of hours with a halogen light for a load and it is quiet and seems to run quite well. Curiously, they recommend a 25 hour break-in at 50% load, which seems more likely closer to the ‘breaking’ period.
    Location: North Central Texas

  • #2
    Unless your fridge is a mini bar fridge, It won't run on that generator. the startup inrush will likey kill the generator.

    Same with any sizable motor load really.

    100v even should'nt really damage anything to be honest, might just underproform a little bit.

    Easyest way to change its voltage... Return it for a new one? :P

    Or buy an "AVR" automatic voltage regulator.. they have a multitap transformer to boost/buck voltage, and relays to alter the taps used as needed.
    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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    • #3
      Most everything is rated at least +/-10%. And anything electronic is almost always 100v-240v input.

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      • #4
        It just needs a 9/64 exhaust and it's ready to go.

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        • #5
          The voltage at your normal wall socket will move around as much as your generator. Even more now that the EPA is forcing the shutdown of diesel generators. It's a good time to buy a "Brown Out Special" home generator. I'm looking for a natural gas version.

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          • #6
            The voltage is not going to be an issue.

            But as BM already said...you will never be able to start a regular house sized fridge with that generator.

            Starting wattage on reactive loads like a fridge typically run up to 3 times of what it uses while running.
            Home, down in the valley behind the Red Angus
            Bad Decisions Make Good Stories​

            Location: British Columbia

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            • #7
              Here's what a quick google search turned up for starting loads:

              http://www.generatorjoe.net/html/startingload.html

              Using this for a typical reefer:
              Refrigerator (frost-free, 16 cubic feet) = 725W

              You probably won't get there. But - you can get a 1500kw APC that you can keep charged from your genny and which will handle the starting load of the reefer. Once the reefer is running the APC cuts off and you run on the genny.

              I buy used APC (tm) battery backups in the 1.5kw range for $5 - $15 at a local PC recycling shop and buy replacement batteries at Fries Electronics for a song.

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              • #8
                Originally posted by dp
                The voltage at your normal wall socket will move around as much as your generator. Even more now that the EPA is forcing the shutdown of diesel generators. It's a good time to buy a "Brown Out Special" home generator. I'm looking for a natural gas version.
                EPA is doing what? I know the listeroids are nat allowed in the country, but if you ever saw one running first hand you would see why.

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                • #9
                  Don't consider this to be the word down from God - take it as a trail head and follow the idea on Google to as many sites as you need to get the drift:

                  http://www.thenewamerican.com/tech-m...-energy-prices

                  CO2 is now a poison, according to the EPA, to be regulated like bovine farts and dichlorodifluoromethane. The linked site has enough keywords to keep you busy until your head explodes.

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                  • #10
                    And.... how are you measuring? The waveform from the small generators is anything but a sine wave. Unless your meter is reading true rms, it may be way off.

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                    • #11
                      Originally posted by lakeside53
                      And.... how are you measuring? The waveform from the small generators is anything but a sine wave. Unless your meter is reading true rms, it may be way off.

                      Who says the outputs are not sine waves? Where did this snippet come from/

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                      • #12
                        Hmm, I think that site might just be a touch biased. As much as I dislike the federal government getting into our lives their notion of just eliminating the EPA is nuts. EPA has been a double sided sword, business and industry has shown over and over that left to their own devices they will do no more than they have to limit and control their pollution. On the other hand EPA has grown more and more power hungry, this whole carbon scheme has got to go.

                        lakeside, they are sine-ish. No where as clean as utility. That can be enough to throw off cheap multimeters.

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                        • #13
                          I was under the impression that even simple alternators produce a good sine way and in fact it is not easy to build an alternator that produces anything else!

                          Utility mains are not perfectly clean as they have to contend with all manner of switching spikes and goodness knows what else.


                          Whatever the problems might be with small alternators I would be suprised if wave form is a major issue.

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                          • #14
                            I take it that the output voltage is not something I can easily change then. I suspect with a full load the voltage will drop further.

                            So, no worries at this point, but at what level should I be concerned about possible damage or reduced lifespan of the load?
                            And yes, am using a true RMS VOM. I absentmindedly grabbed the cheap VOM I keep laying around the shop first, which failed to give a meaningful reading.

                            I should have added this to my original questions:
                            What would be the simplest way to add a 12v outlet?


                            Thanks a bunch for the help guys.
                            Last edited by Joel; 08-27-2011, 05:35 AM.
                            Location: North Central Texas

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                            • #15
                              Adding a 12V outlet. I've bought 2 things off Ebay for $1.70/Delv each that plug in the wall & have a lighter style power port. They work great.
                              "Let me recommend the best medicine in the
                              world: a long journey, at a mild season, through a pleasant
                              country, in easy stages."
                              ~ James Madison

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