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Torque increase or not

  1. Mar 28, 2012 #1
    hi guys new to this forum as of today . im currently buliding my self a little project but before i go out and blow money on parts i was wondering is there any one out there that knows if this will work ive attached a diagram of what i want to do sounds simply enof but will i gain power, torqe on the output to spin a car 12v altanator useing this method ? open to all feed back :)

    what im looking for is the right amount of rpm with torqe and power that will be produced

    the 1.5hp motor is a 240v motor with 7 amps ?
    and of course the flywheel and 10" pullyes are mounted a shaft and ballbearing cuplors to a base

    Attached Files:

  2. jcsd
  3. Mar 28, 2012 #2
    Gearing will only lose power due to inefficiency. If you have 1.5 hp in, the best you can get out is 1.5 hp.

    The gearing only changes torque output and rpm. Also all that matters is the input and output step. The thing in the middle has no bearning on output as it's an idler, (though in this case a big heavy flywheel).

    So in this case your gear ratio input to output is 2:5, 1:2.5
    So you'll get 2.5 times the torque output, but it'll at 0.4x the speed (2.5 times slower)
  4. Mar 28, 2012 #3
    hey chris thank you for info :) .sorry if i sound like a dummy but i just need things a bit clearer for me ..so the flywheel(weighted flywheel ) would not add any increase of torqe ? because that's all im really trying to do. make a motor spin something but gain inertia and spin a out put ( alterantor ) a bit easyer.other than just put a stright pulley from a motor to the alternator with the same 2" pulley on the motor and 5" pulley on the output (alternator) if not how can i make something that a 1.5hp motor will drive a alternator with a bit of help
  5. Mar 28, 2012 #4
    Flywheel would not increase torque at constant output, it would only decrease it (overall) becuase you have to spend time spinning it up, and then keep it spinning.

    I don't really understand what you mean by drive the alternator with a bit of help. You only have the motor inputting power.

    If you don't have enough coming out at the end, you need to use a bigger motor.
  6. Mar 28, 2012 #5
    ok start from scratch , i have a 1.5hp motor and i want to spin a 12v alternator with less load on the 1.5hp motor and not much rpm loss is there any way to do this or best ratio ? in over all im trying to save the 1.5hp motor stress
  7. Mar 28, 2012 #6
    It makes a bit more sense now there is a context.

    Adding a flywheel will increase the load on the motor, as you want to do more with your 1.5hp, but it will reduce the fluctuation of load on the motor.

    If this is constant load, the only way to reduce the load on the motor is make it bigger or reduce the output. If it's a fluctuating load, a flywheel will stop the shock of going from high load to low load, it will act as a buffer.
  8. Mar 28, 2012 #7
    ok thank you if u had to rig up what size pulls weight of flywheel ,would you assume to use and how would you set it up
  9. Mar 28, 2012 #8
    Without a description of what's going on, sizes, loads, design intent etc. It's impossible to say. With the description you've given, the best answer I can give is none or very small.

    The layout you've got would work for what you are saying, I can't say if it would be better or worse than no flywheel, but it would work.
  10. Mar 29, 2012 #9
    thanks chris all i can do is try i guess :)
  11. Mar 29, 2012 #10


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    Staff: Mentor

    Is there a specific load you are trying to power or are you just trying to see what you get?
  12. Apr 3, 2012 #11
    It is quite interesting that, if there is a clutch between the flywheel and motor, the flywheel can actually act like a capacitor in an electrical circuit. Am i right?
  13. Apr 3, 2012 #12

    jack action

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    Science Advisor
    Gold Member

    Actually a clutch would act as a dampening device by converting mechanical energy into heat. This means that the clutch would act like a resistor. The flywheel would act like an inductor. A Ā«mechanicalĀ» capacitor would be a spring.

    More info:
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