Build a simple electric motor, a good Science fair project

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CONSTRUCTION

The tools required to build a Safety Pin Motor.


	Needle Nose or Regular Pliers
	Wire Cutters
	200 grit sandpaper or Utility Knife
	35 mm Film Container or D Cell Battery
	Piece of index card
	Fingernail Polish, optional

Scroll down for construction details.

WINDING THE COIL


	Start by cutting a 4 foot piece of magnet wire. Make a right angle bend about 3 inches from one end of the magnet wire. Starting with the bent end, wrap the wire around a film canister or D cell battery leaving at least three inches free at the end.


	Holding the coil so it doesn't unwind wrap about three turns of the bent end of the wire tightly around the coil. Next wrap the free end several turns around the other side of the coil. The balance of the coil is important so try to get the two wire ends on directly opposite sides of the coil. Using wire cutters trim the wire ends approximately 5/8” long.

STRIPPING THE ENAMEL


	Now scrape or sand the insulation off of ONE side of each of the wire ends. See the sketch of what you are trying to do. If you are using a utility knife to remove the insulation, try scraping with the back of the blade. Depending on the color of the enamel on your wire you might not be able to see what you scraped off.

	Another option is to remove all of the enamel from the ends of the wires and paint half the wire with nail polish. (Sally Hansen Hard as Nails works well) If you use a bright color it is easy to see if you missed a spot or applied too much. If you let your motor run long enough the insulation/nail polish will eventually wear off the wire ends. If that happens, scrape or sand the ends completely clean and apply nail polish.

	Scrape the insulation off the top side of both wires. In this picture, bare wire is blue.		Optionally, scrape all the insulation off the ends of the wires and paint one half of the wire with nail polish. In this picture, bare wire is blue and nail polish is red.

APPLYING THE POLISH

This is an optional step depending on the type of wire you use.

Use the nail polish sparingly. It helps if you have as little nail polish on the bush as possible and paint the coil from the bottom so the polish won't drip down over the clean copper. Let it dry for a few minutes before using the coil.


	ASSEMBLING THE BASE



	Open the safety pins and spread them open a bit. Insert them into the base two inches apart (the width of the C cell) as shown in the photo. Hold the pliers close to the point of the pin as you push it into the wood.

	ASSEMBLING THE MOTOR



	Slip a bead over each end of the wires on the coil and gently spread the safety pins apart and slip the wire ends into the loops of the safety pins. Adjust the balance of the coil by bending the wire ends or sliding the wrapped ends up or down slightly. Once adjusted the coil should spin freely when you give it a spin. If the coil won't spin freely, the motor won't work.

	DONE



	Slip a rubber band over the battery and slip the battery between the heads of the safety pins with the rubber band holding the battery in place. Insert a strip of card stock between the positive battery terminal and the safety pin head to act as a switch. Snap two manets together and place them any side up on the base between the two safety pins. The motor is now complete.

STARTING THE MOTOR


	Remove the strip of card stock from between the battery and safety pin. If your motor is especially well balanced the motor might start spinning right away. If not, give the coil a spin in either direction. The motor will either speed up or slow down and reverse direction

	What happens if the motor doesn't work? Is the battery dead? Check that the ends of the coil are scraped properly? Look at the diagrams. The coil needs to be balanced to spin. Remove the battery and make sure the coil is balanced. Are you sure the wire you used is insulated. If you used bare wire the motor won't work.