Is a PM Generators output greater than an A/C motors input?

Hi, If I powered a permanent magnet generator or a wind turbine with lets say a 1/2 hp A/C motor by directly coupling them together or by the use of a gear reducer would the output watts created by the generator be greater than the wattage needed to run the input motor?
If so then could I then grid tie it into my breaker panel with an inverter and reap the benefits of the extra wattage?

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Is a PM Generators output greater than an A/C motors input?

    Roughly, you will have ~50% losses on the conversion (or even worse).

    There is no way to get more power out of a generator than you put in. Violates the laws of thermodynamic.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2
    System2 Posts: 6,290 admin
    Re: Is a PM Generators output greater than an A/C motors input?
    BB. wrote: »
    Roughly, you will have ~50% losses on the conversion (or even worse).

    There is no way to get more power out of a generator than you put in. Violates the laws of thermodynamic.

    -Bill

    Hi Bill, Thanks for the speedy response. The reason I'm asking this is because I found a website where this guy built a wooden permanent magnet generator and claims by turning it with a power drill it produces more wattage than the input. If you're interested in seeing it I could post the link to it. Mark
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Is a PM Generators output greater than an A/C motors input?
    imac567 wrote: »
    I found a website where this guy built a wooden permanent magnet generator and claims by turning it with a power drill it produces more wattage than the input.

    There have been such disillusioned gentlemen down through history, claiming to have invented perpetual motion devices. Some seem to actually believe they are on to something, others are just plain charletons, but no matter what they are, or into which category they fall, without exception, including this "gentleman", they are wasting their own time and the time of those they manage to suck in.
  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    Re: Is a PM Generators output greater than an A/C motors input?
    imac567 wrote: »
    Hi, If I powered a permanent magnet generator or a wind turbine with lets say a 1/2 hp A/C motor by directly coupling them together or by the use of a gear reducer would the output watts created by the generator be greater than the wattage needed to run the input motor?
    If so then could I then grid tie it into my breaker panel with an inverter and reap the benefits of the extra wattage?

    No. There is no free lunch.

    The First Law of Thermodynamics: Everything goes to, um, fecal matter.

    The Second Law of Thermodynamics: The best you can do is break even.

    The Third Law of Thermodynamics: You can't break even.

    Charlatans from time immemorial have sucked people in with claims of such devices, cars that run on water, etc. If any of them were remotely close to real, we wouldn't have an energy problem. Oh, right, Big Oil is suppressing the technology and will send the black helicopters to get you if you make anything work that threatens their profits. :blush: