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Hydro turbin troubles

Discussion in 'Renewable Energy' started by Kenny P., Nov 19, 2017.

  1. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    Fortunately for you a few basic internet search for topics related to alternating current power generation should give you such an overwhelming amount of information to read though you will busy with it for days. Keywords to use are 'How does' followed by whatever topic you are looking for ending with 'Work?'. The rest is just reading and watching videos.

    Also, his forum, https://forum.allaboutcircuits.com would be a good place to start given they have a excellent archive of study guides and educational reference material.

    Personally if I was you I would take a look at how common automotive alternators are converted to permanent magnet units. Many of the DIY tutorials on that conversion give a pretty good explanation of how three phase power is generated and are very relevant to the DIY home built generator design concepts.
     
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  2. Kenny P.

    Kenny P. New Member

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    I'm on it all for few weeks now, could turn your ceiling fan into a WWII german panzer tank, but still can get juice out of my settings.
    Anyway, all i have with me actually and the few next weeks is the laptop and my turbine, and a part of my workshop.

    Reading some electrotechnique schoolbooks, trying to learn more.

    I got most of the principes, what remains is to fit my settings so i can have a signifiant reading. I'll buy some "scrap automotive" and DC house electronics to play with and get in touch with the subject.
     
  3. Kenny P.

    Kenny P. New Member

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    Here it is, tryed everthing you guy's told me, no power at all and unsignifiant current gets out of a single coil, nothing gets out of a single phase setting and i don't have to tell you i only get a ugly carroussel.

    The problem seems to be that sadly popular homebrew design, i think the power just change direction as the magnetic flux pass over the coil, making 2 power flux hitting each other in the coils and end into nothing out. Made a little wind turbin using a ceiling fan, positioning permanent magnets on the case sides around the soft iron cored coils, i guess that design would work better. What do you think about it?
     
  4. dave

    Dave New Member

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  5. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    If you are running with mis matched phasing and magnetic field polarity plus positions they you won't get anything. As has been commented on earlier generators are not something you can just throw together with random configurations of magnets and coil sets, especially a multi phase output system. To me the #1 issue I see is the mismatch between having a 8 pole rotor and a 6 pole multi phase stator coil set. Geometrically and electrical phasing wise nothing matches properly and thus nothing useful gets done.

    Over the years I have looked t many of the home brew generators system and I have yet to ever see any that I felt were much more than 'got lucky' designs and all of them were far less efficient than most any basic mass produced unit that could have easily been repurposed to work in the applications the homemade one were in.

    Too me coils of magnet wire buried in epoxy attached to plywood or old brake rotors are not good generators. Especially given the time, effort and money spent building them that could have easily purchased good pulleys bearings and proper alternators or DC generators that would have yielded as much output power if not more for the overall effort and work put into them.
     
  6. Pommie

    Pommie Well-Known Member Most Helpful Member

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    The idea that one rotor can be loose and be dragged round by the magnetic field sounds wrong. To produce any power the rotors have to provide torque - your "floating" rotor can't do this.

    Mike.
     
  7. Kenny P.

    Kenny P. New Member

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    You're absolutely right, got more results replacing dc motors electromagnets by permanent magnets and that hydro turbin will probably ends in the creek running a car alternator or a strong low rpm dc motor, anyway. Machined cores helps a lot getting the flux where it's needed.
    I still want to win against this axial flux dynamo,so i study a bit each day and i rewinded the 6 coils with a more flat and larger design. Forget about the 8 poles rotors as it never get aligned with a phase, 12 would be great but 8 inch rotors makes it so close one to another that a coil just eat too many different poles. Wanna get rid of it as soon as possible but i cant throw 100$ oh magnetic wire away so easily!
     
  8. Kenny P.

    Kenny P. New Member

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    ««the loose rotor is to get a perfect rotor alignment, when i'll get a little AC v i'll tight the nut :p
     
  9. Pommie

    Pommie Well-Known Member Most Helpful Member

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    To produce ANY electricity requires work to be done. You cannot do any work without torque and you can't apply torque to a disk that isn't fixed to the axle.

    Mike.
     
  10. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    Then redo the permanent magnet part to have 6 poles that match the coils. Until the geometry of the stator and rotor poles match nothing is going to work properly.
     
  11. Pommie

    Pommie Well-Known Member Most Helpful Member

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    If you have the same number of coils and magnets then all coils will produce the same voltage and you will have a single phase generator and severe cogging. Using 4 magnets to every three coils will produce 3 phase. So 6 coils and 8 magnets is good.

    Mike.
     
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  12. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    Until he can get single phase output to work I wouldn't be all that concerned about doing three phase using a mismatch of things.

    As is, either his geometry is way off or
    the magnets are way too weak or
    the rotor is moving too slow or
    the gap between the magnets and coils is too wide or
    a combination of any number of these issues is in play.

    My guess is the magnets are either too far away from the coils or too weak to generate any workable power given free hanging magnets and air core coils make for a very poor field coupling and thus very poor power production and I think that part of the problem.
     
  13. bryan1

    bryan1 Well-Known Member

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    As this hotch botch of a generator is basically a axial flux arrangement in order to work how many turns are needed a one turn coil is used then measure the voltage produced. Then work out how many turns are need to produce the required voltage.
     
  14. Kenny P.

    Kenny P. New Member

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    I begin to hate axial flux as i get no readings on a single 120 turns coil or even on a 1 turn coil. Last time i had a signifiant reading was on my first 9 coils 12 rectangle ceramic magnets settings. This turbin will ends filled with manufactured motor or alternator coils.
     
  15. Pommie

    Pommie Well-Known Member Most Helpful Member

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    Can you try fixing your "floating" rotor and then just try with one coil. If that doesn't produce some AC then something is very wrong.

    Mike.
     
  16. Kenny P.

    Kenny P. New Member

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    I'm on it for a last "dual 12 magnets rotors, 6 - 19 gauge/120 turns flat coils" on single phase wiring test .

    I'll fix the floating rotor :p
     
  17. Pommie

    Pommie Well-Known Member Most Helpful Member

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    BTW, are your magnets on a metal disc? The metal is required to form part of the magnet circuit.

    Mike.
     
  18. Kenny P.

    Kenny P. New Member

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    Wow! Almost reached 1 volt AC, first reading with those settings. The tork trick did it but i want much more!
     
  19. Kenny P.

    Kenny P. New Member

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    Yes they are on a tin circle of betty crocker oven plate. Maybe i could do better :p
     
  20. Kenny P.

    Kenny P. New Member

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    Test result - 1 volt ac using the drill at high speed. Already reaching 4 volts with the ceiling fan, and much more amps.
     
  21. Pommie

    Pommie Well-Known Member Most Helpful Member

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    The backing metal needs to be substantial which is why people use metal disc brakes. If you only have thin metal then your magnetic field will be very weak and will not generate much voltage at all.

    Mike.
     

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