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How much power motor I need to rotate big ferris wheel

  1. Nov 13, 2014 #1
    Hi Guys,

    I am pleased to join this forum to learn something from experienced guys and thanks in advance for helping me to understand physics.

    I am trying to design a Ferris wheel with maximum SPEED and maximum PASSENGER capacity. I want to know formula to calculate MOTOR POWER IN KW to rotate that Ferris wheel. Here are general specs of the wheel.

    Diameter: 106 Meter
    Radius: 53

    Wheel total weight: 1000 Ton
    Exclude Wheel standing structure: 30%
    Rotating Wheel weight: 700 ton (Everything including spindle, hub, bearing, spoke cables, rim, cabin, riders weight, etc)
    Minutes Per Round: 10 (1 round completed in 10 minutes)
    Round Per Minute: 0.10
    Wheel Speed: .55 meter per second

    For this calculation if only rim, spoke cables, cabin/rider weight is required then you can make rough estimate what might be the weight of spindle, hub, bearing, etc. which are creating force. You can make an assumption and then calculate on that assumption. I will fix formula in Excel as per given here and then adjust weight.

    I want to know
    1. What is total torque generated by wheel (Newton Meters / Joules)
    2. What power motor in HP or KW I needed to rotate this wheel

    Once I get formula then I can set that formula in Excel and try to change speed to find good results.

    Please help me.

    Thanks

    Shaks
     
  2. jcsd
  3. Nov 13, 2014 #2

    Baluncore

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    Science Advisor

    Why are you doing this calculation? Is it a schoolwork project, or do you have a real application?

    Will the riders be distributed evenly around the wheel or might they all be on one side?
    How will you allow for wind speed being greater at the top of the wheel than the bottom?
     
  4. Nov 13, 2014 #3
    Thank you for helping me.

    This is the calculation of real project.

    Yes, rider cabin will be distributed evenly. I don' have idea of wind speed. You can assume that wind is normal. First I need to complete calculation if every thing is normal.

    Thank you
     
  5. Nov 13, 2014 #4

    jack action

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    Gold Member

    The answers from this thread apply to your question. But there is probably some more tedious details to look at for your project that require a high level of expertise (after all, you are basically making a building that can move!)

    A quick number might be obtained from this project as the weight and sizes are very similar to your project. Although I have no clue how they got their numbers.
     
  6. Nov 13, 2014 #5

    Low-Q

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    Gold Member

    The weight of the wheel does not alone tell you how much torque you need to accelerate it at a given rate. It also depends on how the mass is distributed inside its circumference. If most mass is located close to its circumference, you need more torque to start the wheel turning than if most of the mass is located closer to the hub. Because the acceleration closer to the circumference is greater than closer to the hub.
    Also have in mind that some people tend to change their mind and do not join the ride, and there will probably be some uneven distribution of people.
    In a worst case scenario, there is people only on one side of the wheel. If it between close to the top and close to the bottom is as much as 100 people with average weight of 75kg each, you will at 53 meter radius have to fight a torque of 2.7 million Nm - if my calculations are correct.

    Vidar
     
    Last edited: Nov 13, 2014
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