modifying a generator

howdy all- my question is has anyone modified a generator to run off its self after it has started?

so what i envision is a bench grinder with a fan belt pulley mounted next to an alternator from a generator.

grinder is wired to start off from ac with a pigtail going to 15amp socket on alternator. spins the motor spindal from the generator(minus) the motor. once gen set is up to speed, flip switch so grinder is now running from generator. now the generator is running off itself. but i suspect that this may have a ground bonding issue. or the coil in the alternator may need to be modified? depending on the duty of the alternator i suspect that getting another 15amps(to charge battery bank) could be difficult.

any input would be great.


  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: modifying a generator

    I think what you are describing has already been invented. Do a google search on "perpetual motion". --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • BB.
    BB. Super Moderators, Administrators Posts: 33,476 admin
    Re: modifying a generator

    Sounds like you are describing a perpetual motion machine.

    Realistically, such a setup (belts, motor/genset) would be, at best, 50% efficient. You would need >100% energy transfer just to keep the setup running. From what is known today, you cannot get >100% efficient energy transfer.

    One of the "Thermodynamics Jokes":
    • Zeroth: You must play the game.
    • First: You can't win.
    • Second: You can't break even.
    • Third: You can't quit the game.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: modifying a generator

    Yepper, the motor may be 60% efficient, meaning it takes 40% more power to make it run, than it puts out in mechanical power. Then you have added losses in the transfer belt, but you could eliminate that by using direct coupling of motor to generator, shaft to shaft. Now lets look at the generator. It too demands perhaps an extra 40% more mechanical power to turn it than it puts out in electricity. The rest is poured out in heat.
    So what you can do, is hook everything up, get it up and running off grid power, then flip the switch over to self powered and time how many seconds, or fraction of seconds it takes to run out of energy and come to a stop. You'll find the machine will be at a complete stop in roughly 3 to 5 seconds.
    But it will be a learning experience :)
  • Peter_V
    Peter_V Solar Expert Posts: 226 ✭✭✭
    Re: modifying a generator
    vtmaps wrote: »
    I think what you are describing has already been invented. Do a google search on "perpetual motion". --vtMaps

    Naw, everybody knows that perpetual motion is impossible. What most people don't realize is that it doesn't work because of energy build up. What you need is some way to suck off the extra energy and then perpetual motion machines would work and (naturally) power your house at the same time :roll:
  • stillchillin
    stillchillin Registered Users Posts: 55 ✭✭✭
    Re: modifying a generator

    sort of like shining a flood light on your solar array during full sun then have the light still shining at night.
    18- 235 W Kyocera panel, 12- 4-KS-25PS Rolls 1350 Ah, Magnum MS4448PAE, ME RC50, ME AGS, Outback FM 80, Generac 8KW LP generator, 6.5 Honda Portable generator
  • wirenut
    wirenut Registered Users Posts: 22 ✭✭
    Re: modifying a generator

    At just about every home show that I set up my solar booth somebody comes by to tell me how they invented a perpetual motion machine just like you're describing.

    Even if you had 100% efficient motor and alternator and could get it o run forever, you can't pull energy from it so it's still pointless.
    You can't create energy. You can only transform it to different forms.