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David Anthony Colarusso - Sadly not Havoc Dinosaur
Intermittent musings on the law, science, education, technology, design, and life. Also, I build things: furniture, software, reasoned arguments... To learn more about that, click a persona below for my eponymous website.

How to build a simple electric motor, plus how it works.

by David Colarusso - March 3rd, 2007

A fast-paced time-laps demo of how to build your own electric motor, this segment was a lot of fun to make. I hope you enjoy it. Plus, you can now subscribe to the Tabletop Explainer via iTunes.


Also, by popular demand, here’s a TROUBLESHOOTING GUIDE

First, it’s important to understand the context of the “Build Your Own Motor…” video. It’s a demonstration aimed at solidifying the ideas presented in two earlier videos. If you haven’t already, you should watch the whole set:

1) What is the magnetic field?

2) Electricity & Magnetism Hand Rules (part one)

3) How to build a simple electric motor, plus how it works. (above)

The main idea here is that charges moving through a magnetic field experience a “push” perpendicular to the direction of their motion. This force is also dependent upon the direction of the magnetic field. The fact that the wire is stripped on only one side alternates the current from “on” to “off” every half rotation. So halfway through the spin, the ring coasts through until it gets current again receiving a “kick.” It’s a poor man’s commutator. The particulars of this kick/force are discussed in the second video. Armed with the knowledge from the above videos, you should be able to troubleshoot most of the problems that arise. The key is to make sure you understand the concepts first.

That being said, here are the most common issues I’ve seen my students have when working on their motors:

1) They strip the wrong part of the coil.

1.a) Most often they forget that they are supposed to strip only the underside of the wire on the arms of the coil. They mistakenly strip the whole wire. This could cause the coil not to spin properly and also in some cases to over heat.

1.b) They strip the bottom of the wire when the coil is lying down. Make sure you are stripping the underside of the coil when it is oriented as an upstanding “O.” Ask yourself, will the charges flowing through this wire get a push in the right direction according to the rules set out in the second video?

2) The coil isn’t symmetrical. Before you connect up the power, the coil should spin quite well with just a little push. If the arms are off center this can be a problem.

3) The coil isn’t wound tightly enough. The coil should be very tight and neat.

Also you could be using the wrong type of wire. It needs to be thin, but also insulated. I’ve had good luck with this wire.

If something isn’t working ask yourself “why?” You should have enough information to figure out the answer. After all, that’s half the fun. I hope that helps.

Entry Filed under: Electricity & Magnetism

14 Comments Add your own

  • 1. gilbert  |  March 5th, 2008 at 11:05 pm


  • 2. alborz  |  March 18th, 2009 at 4:17 pm

    i have a question? i want to build a electric motor for a class, but we could only use certain metirial (one C battery, very thin copper wire, tape, paper clip, magnets, wooden base.) i build everything but its not its not spining. i think the problem is i have to wrape the cooper wire to a matel stick since the wire is too thin.
    Thank you.

  • 3. Ross Ellicott  |  April 6th, 2009 at 12:31 am

    Fun project and ours works great thanks! Attempting to add additional modern day relevance to this project I hoped to chnge out my AA (AAA) battery for renewable energy via Lemon or Solar. This has proved to be more of a challenge than the DC motor. Have you ever tried running this with an energy other than a battery?

    Also… do we not sand one half of one end to create a break in the circuit and hence a pulse as electricity stops and starts?


  • 4. NYIsles007  |  May 5th, 2009 at 10:32 pm

    Great video. Very helpful.

  • 5. Milton Babb  |  December 8th, 2009 at 3:12 am

    I want to build my own negative ION generator, can you teach me how to?

  • 6. Jagdish Patel  |  February 2nd, 2010 at 2:43 pm

    Please answer the questionaire asked in this video

  • 7. pradeep  |  July 20th, 2010 at 10:51 am

    why do we leave insulation on half wire

  • 8. David Colarusso  |  August 11th, 2010 at 1:39 am

    pradeep, I just added a troubleshooting guide to the article. You might find it helpful.

  • 9. Kevin Electrical  |  September 24th, 2010 at 9:56 am

    Very nice video, I’ve also just subscribe, looking forward to the future posts!

  • 10. Tehmaas  |  July 17th, 2013 at 5:57 am

    first of all its an excellent video.

    Kindly tell me where is the troubleshooting guide and how many turns you made for this motor of the copper wire.

    what gauge wire you are using is it 30,22 or 26 gauge wire.

    how much voltages you supplied to this motor

    and what are the specifications to wound the wire.

    kindly reply as soon as possible
    thank you.

  • 11. rajsarungbam  |  September 5th, 2013 at 10:55 pm

    Very helpful. Why do we sand?

  • 12. David Colarusso  |  October 14th, 2013 at 9:26 pm

    Tehmaas, I’ve added a FAQ to the article. It’s also available as part of the video’s description on YouTube.

  • 13. sam brodsky  |  February 27th, 2015 at 1:11 pm

    i’ve been looking for an animation of this type of motor to help with the class explanation of it (after we build them in class). it’s hard to find! most explanations are animations of a more complicated motor using commutators on the end of the axle.
    -high school engineering teacher

  • 14. Gigialtahan  |  January 20th, 2016 at 1:54 pm

    Hi, may you pls answer my following questions and anyone who can answer my questions here is my email:

    1)what happens if we add more loops?
    2)how do the wires spin?
    3)What can be changed to make the motor turn fater?
    4)What is the effect of the wire on how fast it spins?

    Pls any information can help me for my schools science fair.

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