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Multiple motors to drive a single axle

  1. Mar 16, 2014 #1
    I want to turn an axle or a wheel using multiple motors. With a single motor, sometimes the power is not enough. Is there any method to use two or more motors independently driving the same axle or wheel ? The idea is to have contributions from all the motors so that the axle or the wheel gets enough power to run.
     
  2. jcsd
  3. Mar 16, 2014 #2

    Baluncore

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    Welcome to PF.
    What type of motors are you considering?

    The torque on a DC motor is proportional to current flow.
    Two motors will be able to do twice the work of one.

    To drive one axle, it is often more economic to use one larger motor than several smaller motors.

    The economy of using more than one motor comes where several wheels on a vehicle need to be driven. The smaller motors can be distributed to the wheels, which reduces the need for transmission, drive shafts and CVJs.
     
  4. Mar 16, 2014 #3
    Well...
    Its not a motor actually. Its a wind fan. I want to use this or these to run a turbine. Since the space available is very limited, I want to use several smaller fans running together to drive the turbine.
     
  5. Mar 16, 2014 #4

    Baluncore

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    Sorry about the questions, but I think we may have a problem here with terminology.
    A "Fan" is used to move a fluid such as air, it adds kinetic energy to the fluid.
    A "Turbine" is driven by a moving fluid, it extracts energy from that fluid.

    Is the 'turbine' you refer to, actually being used as a pump to move a different fluid?

    Can you better describe what you are trying to do? wind energy or pump?
     
  6. Mar 17, 2014 #5
    Sorry for the inconvenience. I want to turn rotors using wind power and those rotors will supply that energy to a single generator to produce electricity.
     
  7. Mar 18, 2014 #6

    Baluncore

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    So you have several wind turbines that must be combined to charge say, a single electric battery.
    In effect, you are attempting to harvest widespread energy and gather it all into one place.

    You have a number of challenges. You want the energy derived from the wind turbines to travel in one direction to the battery only, so one turbine does not drive another backwards. You must take only as much energy as is available from any one turbine without stalling it's aerodynamic profile. All turbines must generate their part of the total, no matter how big or small it is compared to the others.

    Using fluids or mechanical linkages to combine turbine rotation is very inefficient and all suffer from the difficulty associated with combining different energy flows. For example, the power transmitted by a shaft is RPM*torque so you would need continuously adjustable gearboxes to combine shafts. With hydraulic systems, each wind turbine would need a variable displacement pump which would be cost prohibitive.

    Really the only technology capable of doing this is electrical. You must get away from one generator and use a small generator on each turbine. The electric power can then be combined by using switching converters to charge a common battery. Switching converters are better than 90% efficient. I can see no way that you can exceed that efficiency using any other technique.

    Now, if someone can prove me wrong, you will have your answer.
     
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