Build a Simple Electric Motor Uses a stator made of windings, an armature with two coils, and a commutator

Safety First This motor should be assembled with adult supervision. Ask an adult to help you with the tools. This motor requires the use of tools that could be dangerous if not handled with care. 2

General Instructions The tools and materials required to build the motor are shown on the next two slides. After these are several slides that describe important dimensions. The rest of the instructions are shown with pictures. 3

Tools Hammer Twist drill or power drill Screwdriver Tin snips Hot glue gun Optional: Soldering iron Vise 4

Materials (1) wood base – 1” x 3-1/2” x 6” white pine (1) 26 gauge wire ~ 85 feet (4) 12d (penny) nails (1) 1/8” x 6” steel rod (this rod needs to be at least 4” long) (4) #6 Wood screws – ½” (2) 3/16” washers (2) copper strips – ¼” x 1” (2) paper clips – standard size (1) electric tape ~ ¾” x 12” (1) masking tape ~ ¾” x 7” (1) duct tape ~ 1” x 12” (1) piece of sandpaper (2) small beads used to make children’s jewelry (1) battery enclosure for (4) AA batteries (1) 3/32” x ½” x 6-1/2” steel strip (stator) (1) 3/32” x ½” x 2” steel strip (armature) Optional: (1) doorbell switch 5

Wooden Base Lay out 2”2” 3”3” 4”4” 4-1/2” 5”5” 6”6” 3/8” 1”1” 1-9/16” 1-7/8” 2”2” 3-1/8” 3-1/2” Nails go in these spots 3/32” holes, ½” deep for stator strip 3/32” holes, ½” deep for brushes 6

Armature Assembly 1-1/2” 2-3/8” 2-7/8” 3-7/8” 6”6” Bead Commutator Armature strip (no wire shown) 7 ¼”¼” 1/8” steel shaft

Armature Assembly (See slide 10 before starting) Using the measurements provided on slide 7, center punch and drill a 1/8” hole in the center of the armature steel strip. Slide the strip onto the shaft and hot glue it at the location specified (see slide 12). Wrap masking tape around each side of the strip on both sides of the shaft. You will need to make two coils for the two electromagnets. Leaving about 3” of wire to connect to the commutator, wrap 20 feet of wire tightly and uniformly along one side of the strip. When you have completed wrapping the wire on one side of the strip, move to the other side of the shaft and, without cutting the wire, wrap another 20 feet of wire. Be sure you wind the wire in the same direction for both coils. When you are finished, make sure you have 3” left to connect the last coil to the commutator. Then, wrap some electric tape (black or different colors around each coil). Scrape 1-1/2” of insulation from each wire using sandpaper. Now, we move to making the commutator. 8

Commutator Assembly (See slide 11 before starting) Using the measurements on slide 7, wrap the 1” wide duct tape around the shaft so it builds up to ¼” diameter. Now, bend the copper strips using two pliers or use a vise and a hammer so they fit along the curvature of the commutator. While holding the copper strips on the commutator, wrap electric wire around each end to hold the strips in place (see slide 11). Solder the wires from the armature coils to each of the copper strips (see slide 11 and 12). 9

Completed Armature Assembly 10

Close-up of Commutator Assembly 11 Yellow electrical tape wrapped around the copper strips

Close-up of Commutator with wires soldered to copper plates 12 Wire from one coil soldered here Wire from second coil soldered here Hot glue armature strip here

Add Spacers See the next slide, slide 14, to determine where the beads should be hot glued to the shaft. You may have to wait until you have completed the next steps before hot gluing them to be sure there is little horizontal movement of the shaft within the armature posts. 13

Armature Assembly with Beads hot glued to shaft 14 Hot glue

Stator, Armature Posts, and Brushes 15 Electromagnet Scrape off 1” of varnish from the wire using sandpaper Stator Armature Post Brushes

Stator Coil Assembly Use the 6-1/2” metal strip and center punch the location of the screw holes ½” and 1” from one end of the strip (see slide 17). Drill through the metal strip with a 3/32” drill bit. Using a vice and hammer, carefully bend the strip at the lines marked in slide 17 to form a “U” shape. Wrap masking tape to cover the center section of the “U” to act as an insulator when winding the coil. Leaving about 8” of wire, carefully wrap tightly and uniformly 40 feet of wire to form the electromagnet shown in slide 15. An 8” lead should be left after you wrap the coil. You can add electric tape (black or other colors around the coil). Screw the stator assembly to the wooden board using the #6 wood screws. 16

Stator Dimensions 17 ½”½” ½”½” 1”1” 2”2” 6-1/2” 4-1/2” Drill 3/32” holes here Bend here

Armature Posts Hammer the four nails in the locations shown on slide 6. Wrap wire around both posts about 1-1/8” above the top of the wooden base. These provide the supports for the steel shaft. 18

Armature Posts 19 Wrap wire around both nails about 1-1/8” from the top of the wooden board.

Close-up of hot glue holding wire to the nails 20 Hot glue holding the wire supports

Brushes Bend each paper clip as shown on slides 15, 19, or 22. Screw the brushes to the wooden base as shown on slide 6. Be sure to use the washers to hold down the paper clip brushes. The brushes should gently touch the copper plates as you turn the armature. 21

Close-up of brushes 22

Brushes touching the space between the copper strips 23

Brushes touching the copper strips 24

Wiring Diagram 25 Battery power source Wires to/from the brushes Doorbell Switch (optional) I like to put on a doorbell to turn the motor on and off. Stator Coil windings

Motor wiring complete – including battery pack and doorbell 26

Working Motor! 27

Final Comments After you have all the materials and tools, it will take you about 1-1/2 hours to complete the project. Troubleshooting: – Be sure your batteries are charged – The brushes should gently touch the commutator – If you don’t solder the armature coils to the copper commutator strips, they must be fastened securely. – Sometimes you may have to give the armature a little twist. Leave me a message on the website if you have any questions or problems with this motor. Good Motoring! 28