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Are there any generators that produce little or no counter torque?

Discussion in 'General Electronics Chat' started by Njguy, Feb 11, 2018 at 5:15 PM.

  1. Njguy

    Njguy Member

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    Maybe a silly question,

    I understand that when an electrical load is placed on a generator, the generator produces a counter torque, thus requiring more power to maintain the rpm. I was just wondering are there any electrical generator designs that produce little or even no counter torque, or would this be considered an impossibility? Doesn't matter if AC or DC generator. Thanks guys.
     
    Last edited: Feb 11, 2018 at 5:23 PM
  2. dknguyen

    dknguyen Well-Known Member

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    No, because then your input RPM and torque (aka input power) are independent of the load (aka a perpetual motion machine).
     
  3. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    No. The production of "counter-torque' is the effect of the transfer of rotational energy from one part of they system to another that's receiving it.

    No free lunch in power and energy transfers and conversions.
     
  4. dave

    Dave New Member

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  5. ronsimpson

    ronsimpson Well-Known Member Most Helpful Member

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    The internet is full of people with free lunch machines. also pills that make certain body parts longer. and roots that cure all kinds of sickness.
     
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  6. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    You found some of my Ex wifes browser history , didn't you? :p

    but what do I know? According to her, at one point, I was a multi thousand year old human-alien hybrid being that was the only logical explanation she could come up with for me being smarter than her, given by her estimates, she was one of the smartest people in the world to have ever lived.

    (seriously, there's no punchline here. It was an honest conversation we had multiple times and once even with her family as witnesses. ) :facepalm:
     
  7. ronsimpson

    ronsimpson Well-Known Member Most Helpful Member

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    Wife, recently commented "You are not a perpetual motion machine."
    "Get off that forum and do something."
     
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  8. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    Mine would sit across the room, on both her laptop plus cell phone doing god knows what online, and complain that I am sitting around online doing nothing of value.

    Then to top it off, constantly ask me to look things up for her, as she sat there with two independant access points to the internet open and running.

    Overunity seemed easier to understand and work with than that woman. :p
     
  9. kinarfi

    kinarfi Well-Known Member

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    Perpetual couch potato with laptop and phone comes to mind for me
     
  10. AnalogKid

    AnalogKid Well-Known Member

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    No.
    Yes. And, we have math for that.

    https://en.wikipedia.org/wiki/Lenz's_law

    ak
     
  11. dr pepper

    dr pepper Well-Known Member Most Helpful Member

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    A generator with zero input torque would break 2 rules, one it would be a free energy or over unity device (not popular on this forum), and the other would be it would need to have zero friction bearings.
     
  12. unclejed613

    unclejed613 Well-Known Member

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    three laws of thermodynamics
    1) there's no such thing as a free lunch
    2) when you eat, you drop crumbs
    3) ants eat the crumbs

    if there were no back-torque, there's no work being done. that's how regenerative braking works on electric cars.
     
    Last edited: Feb 12, 2018 at 8:08 PM
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  13. schmitt trigger

    schmitt trigger Active Member

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    That is the best description of the three laws of thermodynamics I've seen!
     
  14. dr pepper

    dr pepper Well-Known Member Most Helpful Member

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    I'll explain that to the mrs next when she's moaning about crumbs all over the couch.
     
  15. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    It's called an analog tachometer. Speed proportional to voltage generated.

    There is a common regulator used in cassette decks that that basically used Speed = k*Vm - Im*Rm; When Im = 0; speed is proportional to Vm.

    That little generator doesn't generate power and it still has thermal losses.
     
  16. dr pepper

    dr pepper Well-Known Member Most Helpful Member

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    To answer your question Nj yes the concept would be considered impossible, such a device would be an over-unity or free energy machine.

    This is probably irrelevant in this situation however there is one situation where a gen would have very low or zero torque, and that would be if it had a voltage applied to it that overcome the friction & losses in the gen, however if this happened the gen would then be a motor, in industry you often see braking resistors on motor drives to dissipate energy when the motor brakes the load, ie the other way round a motor becomes a generator.
     

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