Introduction: Mini Electric Motor

About: High school Physics & Science teacher for over 18 years. Always getting my hands dirty with little projects and home made gadgets.

This is a really simple and great way to explore electric motors. Kids of all ages will love this and its a great way to see how electricity can be converted into physical motion.

Step 1: Materials

Most of these materials you will have at home.

  • Plastic or foam cup
  • 2 paper clips large is best but small will do
  • AA battery
  • A small donut magnet, about 2 inches in diameter (but any small magnet will do)
  • Coated magnet wire, this is wire that has a "film" or thin coating on it
    • Magnet Wire 26 AWG Gauge Enameled Copper Magnetic Coil Green
  • Some sort of cylinder about the diameter of a quarter, to wrap the wire into a nice tight circle
  • Two pieces of insulated copper wire with the ends exposed
  • Tape
  • Sandpaper any grit

Step 2: Magnetic Coil

Wrap the magnet wire around the cylinder 10 times leaving some extra wire on both ends.

Make sure the extra wire is on opposite ends of the coil.

Carefully remove the coil from the cylinder and then use the ends to wrap around the coil turns at opposite ends to secure the coil.

Keep in mind that you want your coil to remain as close to a circle as you can.

After the coil is secure straighten the extra ends out, these will act as an axis for rotation.

Once you are done you should basically have a coil loop with two axle ends (the extra wire).

Step 3: Bending the Clips

The paper clips will serve two purposes:

  1. To support the coil and allow it to rotate freely.
  2. Conduct electricity to the coil.

Our bends do not have to be perfect and we can always make adjustments later.

The first bend will be to open up the two loops of the clip. Make the bend so that there is a 90 degree angle between the two loops.

The second bend is to open up the small loop to a "V".

The third bend is taking the end of the large loop and at the middle bending it up into a "V".

Repeat this so you have two identical support clips.

FYI I was able to make all the bends using just my fingers but feel free to use pliers, whatever makes it easier for you.

Step 4: Orienting the Mounts

The paper clips will be taped on top of the cup so that the top "V's" will support the coil.

Space the mounts far enough apart do this and so that the clips do not touch.

Check out the example before it gets mounted to the cup.

Step 5: Taping to the Cup

This will be the support and electric supply for the coil.

We need to tape the clips to the cup and have the copper wires secured to the clips so that we can transfer current. We just need some secure contact between the exposed copper and the paper clips, wrapping and twisting the copper around the clips will probably be enough.

Step 6: Optional Step

This next step is optional, I do it simply to reduce the space I need for the final motor.

I cut the cup down to size.

The cup I used has rings that I can follow with a knife, that makes it easier but the cut doesn't need to be perfect.

Step 7: Taping to the Cup Continued...

There are some minor steps to accomplish this but you want to tape it all together so that the coil is supported evenly and able to spin freely.

Step 8: Alternating I?

Electric motors work because of alternating current, i is the symbol used for current.

We are using a battery that delivers direct current, so we need some way to alternate the current.

In this case we want the coil to have current in it every half turn.

This is where the thin green enamel coating comes into play.

We want to carefully sand off only one side (half) of the coating from the ends of the wires, the axles. Make sure you sand both axles on the same side. When done the sanded side should be facing the same direction on both ends.

Also, try to sand with the coil held vertically.

Secure the end of the wire on top of a table at the edge and then lightly press the sandpaper on top of the wire and pull it across in one direction away from the coil, one pass at a time until you can see the copper wire.

When this sanded section is in contact with the paper clips current will pass through the coil creating a magnetic field, that field will either be attracted to or repelled by the magnet we place under the coil.

When the section that still has the coating on it is in contact with the clips, no current will be in the coil essentially shutting off the magnetic field and allowing the coil to continue spinning using the momentum it gained.

This process will continue effectively creating an alternating current that will allow the coil to spin faster.

Step 9: Start Your Engines!

Place the magnet under the coil, connect the battery and let er' rip!

You may need to give the coil a little push...

This is a great project in which you can change things like the # of loops in the coil, the strength of the magnets, the current etc...and see how it changes the speed of the rotations.

Keep in mind, the reverse of what we made is an electric generator, one of the most significant inventions of all time, thank you MICHAEL FARADAY!

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