By Bad Seed
Keeping it simple...Magnetic wire size #26 x 120 turns. ( Coil ) I.D.= 1" x 1 3/8" O.D. ( Slip-rings ) Brass tubing or similar material.. Size of tubing = O.D. of wooden pencil x 3/4" long. ( Wooden Base "bottom view" ) Slots are used to pass jumper wires to connect the battery terminal posts to the vertical brush & speed lever support post, which keeps it nice and neat. ( Rotor Coil ) After winding, slide one of the spli-rings onto the pencil next to the eraser and then insert the pencil between the 60th turn keeping it centered. Now secure it into place by wraping four turns of a stiffer wire, one at each corner next to the pencil as seen in this video. Next, install the last slip-ring and solder it, along with the other one to the coil, but remember to scrape off about a 1/2 inch of insulation prior soldering. ( Soldered Blob ) Now weld a blob of solder on to the eraser side slip-ring ( centered ). This blob acts as a switch / variable resistor and it must be parallel to one side of the coil or the motor will not work properly. The motor`s start up direction is determined by this blob, so flip it 180 degrees to one side or the other depending on your preference. After this is all done, secure the coil and the slip-rings into their place with a dab of hotglue. The U-bracket (distance between = 1 7/8") which holds the four 1/2" diameter x 1/8" thick rare-earth magnets should be parallel and centered with your rotor coil, as seen in this video. The "magnets to coil spacing" is approimately 1/8" which allows for a clean rotation and maximum rpm. Important note: Make sure the magnetic poles facing inward are installed as noted, one north and one south or the motor will not work. The magnets are held into place by each other, one inboard and one outboard, no gluing required. ( Speed Control Lever ) Applying a downward or upward pressure onto this lever changes the resistance which controls the amount of current going to the rotor coil and in turn its speed. ( Motor Current Draw ) 50ma to 250ma. at six volts d/c. The actual cost of materials to build this motor, including the battery holder and its four double-A batteries is around twelve dollars "CAD" or less.