1. ES Lesson 6 Let’s make a DC motor and learn how it works. © 2012 C. Rightmyer, Licensed under The MIT OSI License, 20 July 2012

2. Recall ES demo 5-10. A compass acting like a DC motor + 9 volts

3. A stronger magnetic field is generated when the wire is formed into a coil Adapted from Make: Electronics, O’reilly [Publishing], Charles Platt, 2009 Electromagnetic field induced by current + + - Magnetic field adds in center of circular coil L (in microHenrys) = (approximately) D ^2 x N ^2 / [(18xD) + (40xW)]

4. Compressing the coil generates a magnetic field much like a button magnet. [Intro to College Physics, Appleton-Century-Crofts, R.D. Rusk, 1960]

5. Torque occurs when magnetic fields intersect [Intro to College Physics, Appleton-Century-Crofts, R.D. Rusk, 1960]

6. A DC motor needs commutator slip rings BATTERY [Intro to College Physics, Appleton-Century-Crofts, R.D. Rusk, 1960]

7. How a DC motor works http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/mothow.html

8. ES project 6-1. Make a working DC motor Adapted from [Usborne, Electricity and Magnetism, Adamczyk and Law, 1993] (1)Prepare the stantions. Use needle nose pliers to shape a spiral hook 1½ times around each end of 6” length of straight 20 gauge copper wire. (2) Insert the stantions in pre-drilled holes so that the bottom of both hooks are ¾ of an inch above the platform. (3) Superglue the stantions in place, and then a 1” button magnet between them. 1 ½ inch BE demo 1-13

9. Backup slides

10. Another fun motor demonstration (Step 1) https://www.youtube.com/watch?v=J9b0J29OzAU

11. Another fun motor demonstration (Step 2) https://www.youtube.com/watch?v=J9b0J29OzAU

12. Another fun motor demonstration (Step 3) https://www.youtube.com/watch?v=J9b0J29OzAU