BL Workshop

Build an Electric Motor





This simple motor operates by turning a magnetic field on and off at the proper time.


VIDEO: Watch our simple electric motor in action.

When current flows through the motor’s rotor coil, it generates a magnetic field. (Picture an invisible magnet extending through the center of the ring-like rotor coil.) When you put a permanent magnet near the rotor, the rotor will try to align itself so that the north pole of the “invisible magnet” will face the south pole of the permanent magnet (or vice versa). If the current is turned off before alignment occurs (but while the rotor is still turning), the invisible magnet will cease to exist and momentum will cause the center of the rotor to swing past the permanent magnet. Eventually friction will bring the rotor to a standstill.

If the electrical current is restarted at just the right time, the invisible magnet will re-form and the rotor will continue to spin. This on-off-on-off pattern of the invisible magnet drives the rotor like a small “putt-putt” boat motor.

WHAT YOU’LL NEED

  • 2 Paper clips
  • 4 Tacks
  • 1 Soft wood block, 5 inches long
  • 2 Small round magnets
  • 1 15-inch length of lacquered bell wire (we used 26-gauge wire)
  • Nail polish (any color!)
  • Needle-nose pliers
  • Sandpaper
  • Masking tape
  • White glue or hot glue gun
  • Magic marker or a half-inch diameter dowel
  • 1.5-volt flashlight battery (you might need two batteries)

WHAT YOU’LL DO

Step 1: Rotor Assembly

motor-11.jpgA) Using the sandpaper, scrape one inch of lacquer insulation from each end of the bell wire. This is a critical step.

B) Wrap the wire around the marker or dowel, leaving one inch of each wire end extending from the resulting coil. Use a bit of masking tape to keep the coil from unraveling. The two wire ends must be aligned in a straight line passing through the center of the coil.

motor2.jpgC) Holding the rotor so the coil is vertical, coat the upper half of one of the wire ends with nail polish. Set aside until the nail polish is thoroughly dried. The nail polish will control the flow of current through the coil as the rotor spins, turning the invisible magnet on and off at just the right time.

Step 2: Base Assembly

motor3.jpgA) Using the needle-nose pliers, bend the two paper clips into the shape shown here.

B) Using white glue or a hot glue gun, glue one of the magnets onto the center of the wooden block. When the glue has dried, place the second magnet on top of the glued magnet.

motor4.jpgC) Attach the two bent paper clips to the wooden block on either side of the magnets using the tacks. The upright parts of the paper clips should be about 1 1/2 inches apart.

Step 3: Final Assembly

A) Carefully insert the wire ends of the rotor through the loops of the upper parts of the paper clips.

motor5.jpgB) Run a wire from one of the paper clips to the positive terminal of a flashlight battery. Run a second wire from the other paper clip to the negative terminal of the battery. The rotor should start to spin after being gently flicked with a finger.

TROUBLESHOOTING

This motor is not a precision device, so it might be necessary to fiddle with it in order to get it to work. If the rotor does not spin or spins poorly, try the following:

A) Check the charge on the battery. You might need to connect two 1.5-volt batteries together to get enough power. Never connect more than three volts to your motor.

B) Check the wires connecting the battery terminals to the paper clips. Hint: An easy way to connect the motor to the battery is to use wires fitted with alligator clips, as we did here. Alligator clips can be purchased at hardware stores and electronic outlets.

C) Check the wires extending from the rotor for insulation. If a poor job was done removing the insulation in Step 1, current will not flow in the rotor and the magnetic field will not form.

D) Check the inside loops of the paper clips for dirt, especially if the rotor was inserted before the nail polish dried. Dirt will block the flow of current through the rotor.

E) Check distance of the rotor from the magnet. When the rotor coil is turned vertical to the face of the magnet, the distance between the coil edge and the magnet should be less than 1/8 of an inch. Bend the upper sections of the paper clips slightly to bring the coil closer to the magnet.

F) Center the coil over the magnet. Reposition the coil by bending the upper sections of the paper clips.

Comments about “Build an Electric Motor”

  1. kurby says:

    very very cool

  2. scienceredneck7 says:

    Hey y’all whats up? Im so excited for this project, its gonna be swell y’all! Yee-hah!!!!!

  3. Science spaz 765890 says:

    This projest seems like a great simple way to build an electric motor…. im gonna show my kidz.

  4. bubba09 says:

    hey, well, it fits my motto, simple and easy

  5. bubba09 says:

    this is cool. i built one when i was in 1st grade. it is easy. now i am in 5th

  6. halo says:

    IM SO DOING THIS FOR MY SCIENCE FAIR PROJECT

    This is simple fun and easy =)

  7. z boy says:

    realy fun and realy cool

  8. Andy says:

    can you plug something into it

  9. Scoutmaster11 says:

    This design works well. Other tips: Get the coil to spin easily and balanced (so doesn’t alway stop in same position) before adding battery. Let nail polish dry 4 hours. A very little bit of polish on the paperclips will keep this from working.

  10. cuty says:

    its fantastic!!
    i’ll do this for my science fair project

  11. camper1201 says:

    ths is cool i want to do this

  12. ted says:

    i love all sorts of wires and stuff so i’m think I’m going to do this some day

  13. Geek says:

    I would recommend using a second coil wired in series with the main coil, also, the more turns of the coil you use, the higher the RPM. PLus, you can use a potentiomer to dial up the voltage at your command!

  14. Geek says:

    I would recommend using a second coil wired in series with the main coil, also, the more turns of the coil you use, the higher the RPM.

  15. babby says:

    it is so easy

  16. spyscout123 says:

    hmm I wonder if Ican add on to it

  17. girlscout3010 says:

    ok i have tried this like a million times and it still doesnt wrk.. can anybody help me? my science fair project is due in like two days and i cant get it?!

  18. Ωhorse shoeΩ says:

    awesome! I just have one question, can you make a wooden car go with this?

  19. no duh says:

    this is pretty kool i guess

  20. magoo says:

    that is really cool and works i make my look difrent and alot samaller but same idea

  21. Q-ball says:

    this is so cool man

  22. cookie says:

    its awesome, better than building a volcanoe

  23. ricky says:

    Im making a paper clip motor for school soo hard i wish i could use this one but the one we have to do is soooo much harder

  24. Mabevu says:

    Wonderful project! I hope my learners will look at this.

  25. zan says:

    this is awsome

  26. boy scout billtea! says:

    nice!! it was fun to do!!

  27. gretta says:

    sickness i love it!!!!!!

  28. darth vader says:

    i did this at school and it was awsome

  29. steveo says:

    cool but i dont got the time the project is due tommarow

  30. Shelby. says:

    Hm.

    This doesn’t work for me.

    Dang.

  31. The Freaker says:

    This Is Freaken Cool

  32. mob says:

    i like this project

  33. ben says:

    wow it really spins

  34. Anonymous says:

    and i bet that i am going to win first place out of all schools in waitcontey

  35. Anonymous says:

    $this is a cool project and i am doing this for my science project.$

  36. bookboy87 says:

    I used this in my science fair. 1st prize! Blue ribbon for a 10 minute project!

    7th grade

  37. nikolas says:

    hi I like your inventein

  38. henrike says:

    this is sweet

  39. yankees says:

    coooooool

  40. bas says:

    I cant get this to work!!!

  41. drscience7 says:

    my hobby is building electric robots (not the lego kind) so this could come in handy

  42. toad says:

    I think that this would come in handy

  43. bob the mighty says:

    this is awesome

  44. Boyscout3 says:

    I’m building this for my sciencefair project and the only things about it is the 26 gauge bell wire is hard to find so we used 24 guage bell wire and the bell wire has to be almost perfectly straight or it won’t turn.

  45. boyscoutkid says:

    can u make a “mini-fan” on the motor?

  46. Anonymous says:

    Nice project. Question — on what page of the December 2007 “Boys Life” does this appear on? I can not seem to find it this issue of the magazine?

    “Build an Electric Motor”

    By Richard Grotyohann

    Illustrations by Colin Hayes

    From the December 2007 Boys’ Life magazine

  47. boyscout11 says:

    cool im gonna bild a motor or something electronic soon

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