Help with Water Wheel consturction

Discussion in 'Put Your Questions to the Experts!' started by ChrisN, Jun 26, 2015.

  1. ChrisN

    ChrisN New Member

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    My question is: Will a 5 foot diameter wheel as opposed to a 4 foot diameter wheel give me more torque because the weight is further away from the axis but slower RPM? I just want to run a car alternator. What pulley sizes do I need to get at least 750 RPM. I have a 14", 11", 4" and 3" pulley's. The alternator has a 2 1/2" pulley and I have a counter shaft. My water flow can keep a 2" pipe full all the time. I was thinking of making the water compartments 12" wide & 10" deep on the water wheel.
     
  2. 9anda1f

    9anda1f Administrator Staff Member

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  3. Topher

    Topher Junior Member

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    Greetings,

    This really is the time when you want to do some engineering. See https://en.wikipedia.org/wiki/Water_wheel#Power_calculations for a start.

    I am no expert on water wheels, but it seems clear to me that the diameter of the wheel should be matched to the head. An overshot wheel of 5' for example would require a head (distance from top of water to bottom) of almost 5'. A 4' wheel in that place would be wasting 20% of the potential energy (though not the kinetic part) in the water. The link I gave has an optimal rotational speed, that should tell you what gearing you will need to get 750 rpm at the output. The size of the buckets has been optimized, so look up the parameters for them as well.

    Thank You Kindly,
    Topher
     
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