The Parts

Within this motor, there are four main parts- the field (base) magnet, the armature, the commutator, and a pair of brushes. Keep in mind, though I may say how to construct it, and how I constructed it, a lot of it is improvisation. The original guidelines provided to us, a lot of the times, just didn't cut it. I had to think of my own ways with what I had at my disposal, and what worked for me may often not work for someone else. In this post I will describe the parts, how I built them, and their purpose.

First is the field magnet. First, a "U" shape needs to be created out of metal. This can be done by using either two "L" brackets or simply bending a strip of metal at the ends. The distance between the ends will change depending on how large your nails are for the armature, but the distance between mine is about 4 inches. After this, choose your single strand magnet wire, preferably low gauge (14 or 16) and wrap it around the base of the U around 400 times. I ended up using 20 gauge wire, only because Home Depot and Radio Shack were in no means helpful in supplying wire, and 20 gauge was the lowest gauge I could find in a larger quantity. Leave some extra wire off the end when you are done and tape over the field magnet with electrical tape. Here is how mine turned out:

Here is the field magnet, with the armature inside it.

Next is the armature. Tape your two nails together with electrical tape, find the center, and put your metal rod through. Make sure the nails don't spin freely on the pole. Now, comes the winding. Using 24 or 26 (I used 26) gauge wire, leave some extra before you start, and wind the armature. For this, you start winding to the right, leaving gaps in between each wind, that way on the way back once you reach the end of the nail, you are not overlapping. So, you wind to the end of the nail toward the right and back, then toward the left end of the nail and back. Ideally, the wires should not overlap, it should look very pretty and neat, and all that good stuff. Realistically, if you are someone like me with a patience level of a very impatient puppy, it doesn't end up that way. Don't be afraid to unwrap and rewrap, because the closer you are to perfect the better. Here is what mine ended up looking like:

     Also on the pole you notice the white spool, where the string will go on so you can pull a toy car. For the spool, I cut little pieces of Styrofoam, glues them together, and then put them inside the spool. Then, the pole went through it, and the spool stayed stable on it.
Here is a picture.

     On the bottom is the commutator. I drilled a hole through an old wine cork, and then slid it up the pole. You can really use any cylindrical object that fits on the pole, as long as the diameter is roughly an inch. After this is done, tape two pieces of copper on, leaving a gap between each piece. Tape the excess wire from the armature onto the copper, WITH THE ENAMEL STRIPPED OFF. The gaps on the commutator should be directly in line with the ends of the nails- so two gaps, two ends. Depending on your brushes, the gap should only be a couple of centimeters long. The purpose of these gaps is to give a break in the flow of electricity, that way when the ends of the nails are parallel with the ground, they have no charge and just continue to spin. At this point the charge is back on and they are pulled back to being parellel with the ground with the charges switched, after doing one rotation. So, charge moves them up, gravity moves them down.
    Finally, are the brushes. These are positioned beside the commutator. Using the lamp wire, the multiple strands should be positioned vertically, so that way when the pole spins, the ends of the wire are touching the pieces of copper. Really, you just need to fiddle around with the brushes to find the most effective position. This can really make or break the project.
    That is all of the main parts of this motor! If all of these are sound, then pulling a toy car shouldn't be a big deal (knock on wood).