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Force Needed to Turn Generator at Maximum Output

  1. Mar 11, 2009 #1
    Hi I was hoping someone could tell me the approx. amount of radial force needed to keep a 10000W generator turning while producing maximum output if there is a 1ft pulley connected to it that does the turning.
    Thanks
     
  2. jcsd
  3. Mar 11, 2009 #2

    mgb_phys

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    There shouldn't be any radial force to keep a generator turning.

    Energy is force * distance, and power is energy/time.
    So if you have a 1 metre radius drive wheel on the turbine and a force of 1 newton at the edge pushing it around then the energy for each turn will be 2*pi*1 = 6.3 Joules, if you turn it once/second you will get 6.3Watts.
     
  4. Mar 11, 2009 #3
    When generator has a load on it, it becomes more difficult to turn. So how many N do you need to turn it while it produces 10000W if the drive wheel is 0.3m?
     
  5. Mar 11, 2009 #4

    mgb_phys

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    I could turn it at one rpm with 10,000N or at 60Hz with 2.8N
    Depends on the generator - normally they are designed for a particular speed which depends on the electricty frequency, the number of phases and the generator design.
     
  6. Mar 11, 2009 #5

    russ_watters

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    Assuming perfect conversion of mechanical to electrical work, power=rpm*torque. You should be able to take it from there.
     
  7. Mar 11, 2009 #6
    So if there are 746 watts/horsepower for turning it and the generator frame is 78% efficient. What would the motive force be for my 10,000 watt goal.
     
  8. Mar 11, 2009 #7

    russ_watters

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    C'mon, make an attempt to calculate it with the formula given! This site is for learning, not spoon feeding!
     
  9. Mar 11, 2009 #8
    Power = rpm * torque only in some amazingly bastardized units!

    Power = omega * T = (2*pi*rpm/60) * Torque

    in more conventional SI units.
     
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