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home windmill reconfiguration questions

Discussion in 'General Electronics Discussion' started by desertmac2000, Oct 8, 2019.

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  1. desertmac2000


    Oct 8, 2019
    Hi all,
    First of all, thank you to the site admin for making signing up easy! Five forums I've tried to sign up to today and this is the first one I was successful with!

    I know next to nothing about electronics, so if you reply to me, please keep it in layman terms. I have an idea that I think is far too obvious to not have been thought before, but I know of no one effecting it, so maybe you guys can tell me why.

    I want to buy a home windmill (actually two, but let's just detail one for now) and reconfigure (or machine/make the blades myself) the blades to face flat so I can attach thin canoe-shaped aerodynamic cups to the end of each blade so that making the blades spin requires a wind source from the side instead of from the front facing the windmill. Then I will mount the turbine to a fixed platform at ground level with a small turbo house fan (like the little Honeywell turbo fan) positioned right at the bottom of the blade spans so it blows directly into the canoe scoops and spins the turbine at a constant speed-- which can be calibrated/adjusted to make the turbine spin at optimum rpm for generating closest to the rated output without stressing the turbine.

    As I mentioned in parentheses above, I plan to buy 2 and mount them facing each other so that they would be spun by the same fan, in a relatively open but protected enclosure. What I THINK I would additionally need would be: an inverter (duh), a controller able to shut down each turbine at different times to give them a rest each day IF that is necessary--- and that is one of my main questions for you guys--- and a second fan to likewise shut down periodically to give each turbo fan a rest. I also want to grid-tie my system so I can sell excess power back to the grid. That also means I don't have to charge batteries-- because I'm generating 24/7, with both turbines spinning most of the day or all day if I don't actually need to give the turbines a rest each day.

    So, can anyone tell me if this is practical? If it is, why does no one DO it? The principle I'm operating on here is that a small turbo fan uses a very small amount of power to spin two turbines that will generate many times the power used by the fan, while never being subject to weather or variable wind speeds.

    I really appreciate any info anyone can give me on this.
  2. Nanren888


    Nov 8, 2015
    Short answer: Sorry, not going to work. Output cannot exceed input.

    Electrical power in to fan
    some losses in fan motor
    Fan converts electrical power to rotation of vanes which moves air
    some looses in conversion to wind
    Your windmill vanes pick up a proportion of this wind energy
    some losses to wind that misses the vanes
    Vanes turning converted to electrical energy in the generator
    Some electrical losses in conversion
    So far we've only lost power, that is we get out less than we put in.
    Net effect is loss.
    So, sorry, but disconnect the input power source and connect output to input and rather than perpetual motion it will stop.
    Generally we can convert energy, but we always loose a little, or a lot, in the conversion.
    Wind turbines gain by using a small proportion of the surroundiing power from the wind that they don't have to produce.
    Hydro generation uses, usually, falling water raised up high by the sun and accelerated downwards by gravity.
    They all have a source of energy greater than that they produce. They all convert, transform, with some loss.
    Any time that you seem to be getting something out for nothing going in, look for something else going in, or where the misunderstanding or scam is.
    That thing known as "perpetual motion" of getting even continuous motion (no output power used) without an energy input can't be done.
    You could consider mounting the wind generator outside in the wind. Wind is basically a free source of energy.
    duke37 likes this.
  3. duke37


    Jan 9, 2011
    You will only capture energy if the wind is blowing. Too little wind means the turbine will not turn, too much and the turbine will disintegrate.
    Most tubines have horizontal shafts but some have vertical shafts to use wind from any direction.
    You could try cutting a 40 gallon oil drum down to make two scoops fitted to a vertical axis.
  4. desertmac2000


    Oct 8, 2019

    Hey Nanren888,
    Thanks for replying. Let me clarify: I had no illusions this was a perpetual motion scenario. And let me give more detail:
    This windmill on Amazon generates 2000 watts+
    Low wind speed rated wind turbine for home, business, or remote use with the Freedom II Permanent Magnet Generator (PMG) - 2000 Watts plus potential power! Raptor Generation 4 carbon fiber blades self regulate their speed in high winds and are aerodynamically tapered blades for maximum output (also available in 7 and 9 blade or our Falcon 4 80" blade models).
    Our newest innovation in power generation! Freedom Permanent II Magnet Generator (PMG) - This is our highest amp model - Up to 2000 watts of output! NO COGGING - Cut in wind speed of 6 MPH
    NEW for June 2018! Our Freedom I and Freedom II PMGs are now designed with a keyed shaft and hub stabilizer as well as includes a self-tightening cam-lock washer to prevent the blade set from ever spinning on the shaft.

    I plan to replace the blades with flat ones with the canoe-shaped scoops on the ends I described earlier (I have experience fabricating, so I can make uniform blades)

    And the fan I'll use is:
    Vent vp-25 air mover contains a 3-speed 1/4 HP enclosed motor and pulls only 2.1 Amp on high, great for placing carpet blowers for those hard to reach places
    Carpet drying fan with daisy chain capability enable users to connect to 5 air movers while using just 1 outlet, this allows to operate more equipment while creating a dynamic drying vortex
    Durable long-lasting roto-molded housing that is ETL certified and listed reliable air mover, we stand by our product with a 5-year housing warranty
    Motor 1/4 HP, Amp L 1.7 Amp/M 1.8 Amp/H 2.1 Amp
    Maximum air volume: 900 CFM, speeds 3
    Certification: C-ETL-US stackable: 5 units, daisy chain: yes
    Voltage 115-Volt cycle 60 Hz maximum static pressure:1.3 in.
    Size: 12.8 in. L x 12.4 in. W x 13.3 in. H wheel speed L 1060 RPM/M 1370 RPM/H 1600 RPM, attached cord 10 ft. 14 AWG
    Stackable: 5 units
    Daisy chain: yes
    Voltage: 115-Volt
    Cycle 60 Hz
    Maximum static pressure: 1.3 in.
    Weight net/gross: 11.3 lbs. / 12.6 lbs.
    Size: 12.8 in. L x 12.4 in. W x 13.3 in. H
    Wheel speed (RPM): L 1060/M 1370/H 1600

    I will mount the fan, which is a carpet dryer, designed to concentrate the flow down to a (roughly) 1,1/2" x 5" opening, and build an attached wind tunnel to further focus the output on the blade scoops.

    If the fan is using only 2.1 Amp on high (I don't know what that translates in watts) and it's driving a turbine that produces 2000 watts+ at optimum speed, I don't see how this could possibly be a wash in output.
  5. Nanren888


    Nov 8, 2015
    Sorry, I think a typo or auto-correct got your last line.
    The energy out is never going to exceed the total energy in.
    Any generator rating will be spec'ed at an input sufficient to create that output.
    If a generator is spec'ed at 2000 watts at optimum speed, then it's going to take more than 2000 watts to get it to running at optimum speed and producing that output.
    I've tried to clear up that useful output is always less than input. It's a physical law you can't really get round.
    Sorry, if I have not explained that well or convinced you. Wouldn't like to see you waste too much time or money on trying.
    I'm afraid this thread is probably not going anywhere useful. This forum is reasonably active and well moderated. I'd expect relegation of this thread to a different category in the forum relatively soon.
  6. duke37


    Jan 9, 2011
    1/4 hp = 136W out
    115*2.1= 231W in and there is fan inefficiency (30%?) to take unto account.
    I suggest you do some sums.
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