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Hydro powered mini saw

Discussion in 'Renewable Energy' started by SexySmart, Sep 30, 2015.

  1. SexySmart

    SexySmart New Member

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    Hi, I’m extremely new to this world of electronics and mechanical systems. But, I still would like to go more green so I’m testing the waters here. Speaking of water I have this idea of basically a miniature hydro powered saw and would like to know if its practical or even possible. The saw itself would be about 3 inches in diameter and strong enough to cut through an apple (not wood or anything). I was inspired by watching a youtube video where I saw this scientist make a mini wind turbine that could power a cell phone. So my thoughts are to replace the wind with a flow of water and replace the cell phone with a lithium battery to power the saw. Ok, so this might be a completely stupid question for you all but is it possible to have water turning the motor to generate power to charge the battery that powers the saw all while getting wet? LOL! Or is this just completely wrong? Any thoughts? Thanks!
     
  2. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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    What the intended application of an apple saw, making apple sauce?

    John
     
  3. SexySmart

    SexySmart New Member

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    I was using the apple as an example of something semi soft to cut but yes kind of like a smoothie maker triggered by running liquid. The saw doesn't need to be powerful enough to cut wood. Everything has to be small which limits it's power correct? Everything has to fit within the 3 diameters.
     
    Last edited: Sep 30, 2015
  4. dave

    Dave New Member

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  5. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    You're thinking too 'electrically' - use the hydro power to directly feed the saw blade - this was a VERY, VERY common technique back in the water powered mills days.
     
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  6. alec_t

    alec_t Well-Known Member Most Helpful Member

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    That would be wasting available energy. Use the water flow to power a water-wheel which drives the saw directly .... as it was done a few centuries ago ;).
     
  7. SexySmart

    SexySmart New Member

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    The water flow is only as strong as what would come out of a kitchen faucet. I'm not sure if that would be strong enough for the saw to cut through an apple. I was thinking it might be strong enough to keep the battery somewhat charged so that the battery can power the saw. Or at least make the battery last a lot longer.
     
  8. SexySmart

    SexySmart New Member

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    The water flow is about as much as a toilet flush. I'm not sure if thats enough to power the saw on its own.
     
  9. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    You're just wasting energy doing the multiple conversions - if you're OK with charging the battery for a long time, and then powering the saw from it for a short time - why not just store the water and discharge that more rapidly to run the saw?, no wasteful conversions required.
     
  10. SexySmart

    SexySmart New Member

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    I’m needing more of a closed system that’s automated and all you need to do is change the battery every few months. So for our go green apple sauce making machine, it fits at the bottom of a large glass and there is kind of a water turbine head on a small generator (dc motor I guess). The consumer puts an apple in the glass and runs water from the faucet in the cup. The running water turns the water turbine and generates electricity to charge a battery. The battery is connected to the motor with a saw head and chops up the apple mixing it with the water.


    Ok, so that’s the idea but you’re saying I’m wasting energy. So given that the water stream a lone probably isn’t enough to power the saw enough to cut through an apple, is my idea not possible? Should I skip thinking about the whole water power all together and just use the battery? If so, what would be the best kind of battery that can last several months powering a saw for a few seconds 2-3 times a day?
     
  11. Dr_Doggy

    Dr_Doggy Well-Known Member

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    Ein = Eout, efficiency says cut out the middle men hence why they say to just hook saw direct to water wheel,

    furst you would need to determine saw power * time , then a water generator powerful enough * time, then power it with the water required. plus volt conversion devices if the two arn't compatible,

    more efficiency = less middle men

    basically you need to know saw power consumption before you can energize it

    personally this is what i would do!:

    crazy Russians!
     
  12. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    May as well just use a battery, as the charging cycle is much too small to do anything worthwhile - running it for a few seconds isn't going to provide any charge worth mentioning.
     
  13. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    Use the rule of 1500 for figuring things out dealing with water and mechanical power.

    1 horsepower (746 watts) = 1500 gallons per minute @ 1 PSI
    Or 1 horsepower (746 watts) - 1 Gallon per minute @ 1500 PSI
    Or any combinations of the two that multiply out to 1500.

    Also figure the typical human can produce ~ 1/10 of a horsepower continuously.

    Given all of that if you are really going green on applesauce just mash and process the damn things by hand. You will be power, time and money ahead in the end.
     
  14. Miho

    Miho New Member

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    It, probably, for girls ;) (or for one little finger?)
    ~200W, I think. Well, human weak beast.

    Super green idea: wife+exercise bike+wasted servo from work. Yet I received a slap from his wife 4 this idea :troll:
    although wind turbines more dangerous.
     
  15. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    Contrary to the vast majority of people's thinking and egos human power output is a well-studied science and the overall numbers say that the average person is good for ~75 watts continuous duty or about 1/10th of a HP. https://en.wikipedia.org/wiki/Human_power

    Also with real horses just as humans they have peak capacity well above their continuous capacity. A good workhorse can top 15 HP equivalent outputs for short periods but for a long haul full days work they are the defining standard for 1 HP in the end.
     
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  16. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    I've always described it as 'able to run a 60W bulb' - but that's probably because you don't get 75W bulbs :p
     

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