Simple Homopolar Electric Motor




Here's a video I made a while back. It has had some pretty amazing popularity around the web and I thought I might as well include it here. It is not unique, but hopefully the video is helpful to some of you.



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    48 Discussions


    Reply 7 years ago on Introduction

    It is a phenomenon, though not so small in my opinion. Any way the motor works just fine and fancy it is.
    Phenomena of this kind have been described by physicists and electrical engineers for some decades. One wikipedia entry could be Force on a current-carrying wire . The formula which describes the force in case of a straight, stationary wire shows that the force is proportional, among other factors, to the current. In this case the current is significant, since it is a short-circuit current. This example of electrical engine is cute and fancy. Watching the video was great fun.
    In the pictures below I tried to draw the model and the circuit.

    simple electrical motor - model.pngSimple electrical motor - circuit.png

    Reply 8 years ago on Introduction

    No, use copper wire (not ferromagnetic) and a neodynium magnet with the silver metallic coating. The magnet has to be conductive and the wire has to NOT be attracted to a magnet.

    Yes, in fact the video has a link to another version of teh motor that uses a very small magnet. I guess there is some limit to how small the magnet can be.


    9 years ago on Introduction

     So I am about 90% sure this is what is going on. What you have is a current that is flowing. Any flowing electric current produces a magnetic field and the the same way a moving magnetic field produces a current.

    What is happening is that because the wire is coiled in a spiral, it is creating a magnetic field that is at an angle to field of the magnetic field of the magnet. This creates a force which spins the wire. Because turning the wire turns the magnetic field, it keeps on turning.

    You could test this by 1) Reversing the turns to see if it reverses. or 2 Reversing the magnet which should also reverse it. If it's just "running away" then the magnet direction shouldn't matter.

    2 replies

    Reply 9 years ago on Introduction

     Just thought about it one more time, and reversing the coil won't work, but reversing the current, or the magnet will.