Paperclip Motor

thingiverse

This is a simple electric motor powered by a single AA battery that's perfect for science classes, physics labs, or fun weekend projects with your kids to demonstrate basic principles of electromagnetism. The motor uses inertia and magnetic attractive and repulsive forces to maintain rotational motion without commutation, making it an exciting and educational project. The electromagnetic coil relies on the principle that magnetic flux F = N * I, where N is the number of turns of wire around the bobbin and I is the current flowing through the wire. Increasing the number of turns or increasing the current increases the magnetic field generated. However, increasing the number of turns requires more wire, which increases the resistance of the circuit resulting in a decrease in current. Can you find the optimum balance of turns/current to maximize the magnetic flux? The motor consists of three 3D printed parts: (1) Simple Bobbin, (2) Fan (optional for decoration), and (3) AA battery holder remixed from enif's Flexing battery holders with integrated spring. Additional materials needed to construct the paperclip motor include: * 2 Number 1 size paperclips * 1 AA Battery * 1-4 Magnets (suggest >18mm or 5/8" in diameter) * ~50cm or 20" of 22AWG enamel coated wire * 1 small cork or piece of foam To assemble the motor, follow these steps: * Straighten one leg of each paperclip so that it is relatively straight. Bend the other loop to create a "U" shaped cup for the axle to sit in. * Insert one paperclip into the hole and indentation at the negative end of the battery holder. Insert the AA battery slightly to hold the paperclip in place. * Insert the second paperclip into the hole and indentation at the positive end of the battery holder and push the AA battery so that it is completely inserted. * Place the magnets on top of the battery in the center. * Wind the wire around the small bobbin, leaving enough wire to form the axle (about 40mm or 1.5"). * Remove the enamel from each axle end of the wire using sandpaper or a small precision file. * Straighten the axles - the straighter and more balanced you get them, the better chance you have of getting continual rotation. To Operate: * Place the wire/bobbin assembly so that the axles rest in the "U" shape of the paperclips and the bobbin is positioned directly over top the magnet(s). * Position the paperclips so that the bobbin comes as close as possible to the magnets without hitting them. * Give the axle a little twist to get it started (if you use the fan blade, you can blow on it to get it rotating). Sometimes it's a bit difficult to get started. If you have trouble, observe the axle/bobbin as you manually rotate the motor. If you notice excessive wobble or if the weight of the bobbin/wire is off-center, then readjust and try again. Adding more magnets side-by-side on the battery (with the poles all facing the same direction) can provide more force. Once the motor has run for awhile, carbon buildup can occur on the copper axles and paperclips where they contact; simply clean with sandpaper or a file to remove the carbon buildup and restore conductivity. If the wire/bobbin does not get warm to the touch after a few seconds of sitting in the paperclips, either there is poor conductivity (sandpaper the axles and paperclips again) or the battery is too dead to power it (replace the battery). My prototype ran for over four hours straight on a single AA battery. I hope you enjoy this fun and easy to make project! Printer Settings: * Printer Brand: MakerGear * Printer Model: M2 * Rafts: No * Supports: Yes * Resolution: 0.2mm layers * Infill: 30% * Notes: No supports are usually needed for the fan or the AA battery holder, but supports are required for the bobbin around the perimeter to provide support for the upper "lip" when printed on its side (as shown in the 3D model).