How to build a simple electric motor

Today, I am going to demonstrate how to make a simple electric motor. This is a great activity for kids and adults, on rainy days or for science fairs. I’ve done this one with kids aged 8-12 ish, but it is a good all-ages activity, depending upon the amount of preparation you can do in advance, as well as the amount of help you are able to give while running the activity.

There are many different electric motor activities out there, with hundreds of minor variations. Mine is based upon this one with modifications to make it cheaper, as well as to use materials I already had available.

First off, here is what the finished product looks like when it is running:

Tools needed include:

  • pliers (1 or 2 pairs)
  • glue gun and glue
  • scissors
  • small piece of sandpaper
  • pencil
  • a glue stick tube (or other small tube-shaped object to wind the wire around)

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Consumables needed include:

  • base of some sort (any kind of scrap wood will do) about 15 cm square
  • 4 large safety pins
  • copper wire (22-26 gauge enameled, approximately 60 cm of wire per motor)
  • ferrite magnet (disc or doughnut shaped)
  • copper tape (wire can be substituted, approximately 15 cm long)
  • 1 AA battery

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Take your battery, place it close to an edge of the board, and center it. Mark its ends with the pencil to use as a reference point when gluing down the safety pins later.

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Here’s your board with the marks. Now we need to bend the safety pins.

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Using 1 or 2 pliers, take a safety pin, and bend it at a 90 degree angle at its middle. Using 2 pliers isn’t mandatory, however, it does decrease the chances of getting accidentally poked by a stray safety pin.

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90 degree goodness.

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Repeat the bending for all 4 safety pins, and line them up for a nice photo for your blog:

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Next, we will glue down two safety pins to act as the battery holder. Going back to our board with the pencil markings, put a drop of hot glue approximately 1-2 cm behind one of the pencil markings.

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Put the safety pin in the glue, with the loop side in the air.

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Throw more hot glue on top to help hold it in place.

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Repeat for all 4 safety pins. The second set of safety pins can be glued in approximately the same position on the opposing edge to the battery holder, but as you will see in a moment, their spacing doesn’t need to be nearly as precise. These second two safety pins will act as your motor mount.

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Next, add a dollop of hot glue to one side of the magnet:

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Now place the magnet glue side down between the two motor mount safety pins:

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Now, I use copper tape because it is cheap, convenient, and I have access to it. You can substitute wire, or even tin foil, to make the electrical connections from the battery safety pins to the motor mount safety pins.

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Cut two thin strips of copper tape, and check they are long enough to reach between the safety pins (again, you can substitute wires or tinfoil).

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Once you are sure they will fit, remove the adhesive backing and wrap them around your safety pins, like so:

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Another angle. Nearly done.

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Now, add your battery. You might have to bend the safety pins to get the copper tape to touch the battery’s contacts. It is better to make these adjustments now before you add the moving part.

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Now, lets make our coil. You will need approximately 60 cm of enameled copper wire, a small diameter tube for your form (I used a glue stick tube) and a small piece of sandpaper.

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Take the wire, and start by leaving a 5 cm tail on one side, and then wrap it around the tube 10-12 times. You will be left with a long tail on the opposite side. You want the long tail.

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Be careful when taking the coil off the tube so it doesn’t unwind on you. Now wrap the short end 1-2 times around the coil to help hold it in place, and unwind the long end so it hangs off the wrapped side as well.

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Take the long end, and string it across the diameter of the coil, then wrap it around the opposite side, so it looks like this:

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Now, this is the trick that makes it all work. Hold the coil up, between your fingers, and rest one of the tails on the edge of a table. Take the sandpaper, and rub of the enamel off on one side of the tail. Rotate the coil so the other tail is facing the same direction, and take the sandpaper again, and rub off the enamel on the one side of the other tail. When you are done, both tails should have the enamel rubbed off the same side.

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Now you are ready to insert your coil. Cut the tails shorter if you have to in order for them to fit into the motor mount safety pins. The tails go into the loops. Give the coil a spin, and if you’re lucky, it will start on the first try. If it doesn’t start, don’t worry, there is a lot of fine tuning you can do to make it work better.

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Now, about that fine tuning: you should have a running motor once you insert the coil. You may have to squeeze the coil so it is oval-shaped in order to get it to fit over the magnet so it doesn’t touch (as I had to) or you may have to play with the battery to ensure a good electrical connection is being made (this is where having a multimeter would come in handy for debugging purposes). The other helpful thing to do is balance your coil so it spins easily and freely, ideally not favoring one side over the other. When you’re done, you’ll have a running motor!

 

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