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Beginner Induction/Motor question

  1. Nov 12, 2015 #1
    I'm starting to wrap my head around the more difficult aspects of electromagnetism, but I'm having a hard time finding a simpler answer to what should be a fairly simple question. What are the basic components of induction, and how much effect does each part have on the output?

    As far as I understand, the materials used, the speed, and possibly the mass all play factors. I realize there are different types of motors, but apart from the way they are arranged (and the materials used), I think the concept is the same. So what creates the 'power'? There's a whole list of questions coming, so even just answering one is appreciated :).

    The materials and their magnetic properties obviously determine some of the power in the right arrangement. Does the size or mass of the magnet make a difference in the output? And does that need to be balanced through all the materials? In other words, if you have two motors that are identical in all ways, except one is 5 times larger, will it put out proportionally more power? Or would adding more permanent magnets by ratio add to the power output?

    What's the correlation (if any) of speed and mass? If I'm cranking a motor, or waving two magnets near each other (with the appropriate circuit), how do the speed and mass of the system compare? Would you get comparable power out of a setup with one small magnet moving very quickly, compared to a large magnet moving slowly? And instead of the single large magnet, would it be better to have multiple magnets running multiple motors instead of a single large motor?

    Again, I know I asked a lot of questions. Please feel free to pick at one of them, or all of them. I appreciate the help. I'd like to test these concepts in real life, but unfortunately that's not very feasible right now.
  2. jcsd
  3. Nov 12, 2015 #2


    Staff: Mentor

    YouTube is a good place to start your learning. Search for "electric motor" tutorial" on YouTube.com
  4. Nov 13, 2015 #3


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    I think "Electromechanical energy conversion" is what you should begin with. Magnetic field is a medium which is necessary for conversion of energy from electrical to mechanical and vice versa. Besides,there are many electrical machinery experts here on PF who can guide you conceptually.
  5. Nov 13, 2015 #4


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  6. Nov 14, 2015 #5


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    Yet another link:
    http://academic.cuesta.edu/ballen/resumes/electromechanical/Basic%20Motor%20Theory%E2%80%9D.pdf [Broken]
    Last edited by a moderator: May 7, 2017
  7. Nov 14, 2015 #6
    Thank you all for the links. I have a clearer understanding. I'm still having a hard time finding information on input force (and resistance) for generators. I don't know if any of you are familiar with the wind belt generator... it hasn't had any press for a while. But it seems like a good easy example of using a very basic physical movement to power a generator (in this case, it uses flutter to generate the motion that brings a magnet between two coils). The force for the motion comes from the wind, as any other wind generator, but I'm trying to conceptualize how much force really plays into the equation.

    By the formulas, the power of the magnet and size would be factors. But with a more powerful magnet that was the same mass, you should need less force to produce the same amount of output. Basically, I'm trying to find out how to balance the input of power with the output. Permanent magnets seem to store energy, or at least, have already set up a flow of electrons in a certain direction; kind of like water almost always goes down a river because it's the channel of least resistance.

    So in a case like the wind belt, would it generally put out more power by moving the magnet between the coils faster, or by simply building a bigger system (requiring more force of wind to move the magnet)?
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