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Coil with iron core as a generator

Discussion in 'General Electronics Discussion' started by Perun, Nov 30, 2015.

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  1. Perun

    Perun

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    Nov 30, 2015
  2. dorke

    dorke

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    Jun 20, 2015
    Generally, for a given coil shape:
    the factor that matters is the magnetic permeability of the core μ.
    The larger the μ, the larger the induced voltage.
    You should use iron core, and you can make it yourself.
     
    Last edited by a moderator: Dec 8, 2015
  3. Perun

    Perun

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    Nov 30, 2015
    Thank you on a answer.
    Just one more question, would be better to do coils like this on picture below, from one piece of magnet wire or individual coils wold be better (seperate coils are easier to replace,that is obvious) im interested in power production.
    Sorry im newbie in electronics at least in magnetic field theory so i need some help :)
    WP_20151207_22_27_11_Pro.jpg
     
    Last edited by a moderator: Dec 8, 2015
  4. dorke

    dorke

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    Jun 20, 2015
    What do you mean when saying "power production."
    Are you looking at a bicycles or something else?
     
  5. Perun

    Perun

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    Nov 30, 2015
    Well i would like to get the most power out of the device.
    I plan to power front and back light on bike all LED, and maybe a smartphone charger.
    So i wanna be sure ill get enough of watts, when i filter out current.
     
    Last edited by a moderator: Dec 8, 2015
  6. Alec_t

    Alec_t

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    Jul 7, 2015
    Individual coils will be far easier to wind. Core pole piece geometry and positioning as close to the magnet path as possible will be critical for maximum efficiency.
    I'd forget about the phone charger if I were you. It will take a month of Sundays to fully charge a phone by pedalling ;).
     
  7. Perun

    Perun

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    Nov 30, 2015
    No phone charger even if lights are off?
    Would be nice to have some power output estimation etc...
    But that depends on many things...number of coils,coil design,positioning on the wheel,magnets used...
    Thanks on answers.
     
  8. Alec_t

    Alec_t

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    Jul 7, 2015
    Given that the average power output of an average human over a working day might be only 100W, most of that would be used in propelling your bike. Let's say you have a spare 10W or so for powering your generator, and the generator efficiency is 10% (including conversion to a steady 5V for charging a phone), that means you could pump 1W into the phone. A typical 1500mAh battery at 3.7V stores 5.6Wh of energy, so even with 100% charging efficiency would take 5.6 hours to fully charge from empty. Admittedly not quite a month of Sundays :). Your mileage may vary.
     
    Perun likes this.
  9. Perun

    Perun

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    Nov 30, 2015
    Thanks Alec on nice anwers :D.
    Well maybe its better that way, with lights only, if i could get more power i would probably end in shield system and a phasor gun :D
    But for a bicycle lights this is almost perfect,most bicyiclers hate battery powered ligths and dynamos are last option.
     
  10. dorke

    dorke

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    Jun 20, 2015
    Perun,

    Some notes:
    1)Your drawing at reply #3 may suggest you plan to put the coils on the spokes of the wheel.
    That is obviously not the way to go:
    The Magnet(s) go on the spokes (moving)
    The Coil(s) go on the Nave(stationary).

    2)Use a filter electrolytic capacitor on the output of the bridge to eliminate the flicker of the front white LED(s).
    On the rear red LED(s) the flicker may be desirable.

    3)If more than one LED is used connect the LEDs in series,in any case use a series resistor.
    The value of the resistor should be calculated according to the DC voltage on the Cap and the specs of the LEDs you use.

    4) The drawing shows the use of schottky diodes(better efficency),but the guy build it with regular Si diode bridge.

    5)Experiment with the number of coils and Magnets to get your optimum design.

    Here is a modified diagram:


    FrictionLessDynamoSchematic.JPG
     

    Attached Files:

  11. Perun

    Perun

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    Nov 30, 2015
    Thanks,i know all that you enumerated except for a 4th thanks on reminder :).
    Im having the most difficulties with the generator itself,i cant find on web anything similar,except traditional generators/motors,
    at least usefull in my case.
    In short i know quite enough about DC,AC, i stopped my hobbyst education at magnetic fields and motors/generators beacuse it was to much time consuming for me ( mathematics especially,triple integrals are scary and most of diffirential equations :D ).
    On my drawing above it is as you say the bottom disc is holder for magnets which is static on the frame on bicycle.
    P.S I like this app for online circuits,it is nice and simple: http://www.falstad.com/circuit/
     
    Last edited: Dec 9, 2015
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