November 13, 2014 ENGR B47 Introduction to Engineering & Design Week #12 Electrical Motors (And Analysis and Technical Writing)

Very Brief Overview Build a motor Quantify its performance Write a manual for its use

Basics of Magnetism [walk-through on whiteboard] Permanent magnets –Likes repel –Opposites attract –Draw “field lines” represent this behavior Electromagnets –Relationship between current & magnetic field –Straight wires and loops

Building a Motor (Conceptually) [walk-through on whiteboard] Permanent magnets –Two fixed on the outside –One rotating in the center Can get a “motor” to work for half a rotation “Flip a switch” and change the magnet?

Building a Motor (Conceptually) What would it look like? Graphics from pcbheaven.com

Graphics from pcbheaven.com

How Can We Make That Happen? Graphics from pcbheaven.com

Graphics from pcbheaven.com

Motor Project Goals Construct a motor Characterize performance (see worksheet on course website) –Speed vs. Torque curve –Power vs. Torque curve –Maximum Power calculation Create instruction manual –Audience is middle school students –Include assembly guide & component list –Step-by-step instructions (lots of pictures!) –Troubleshooting section

How Will Your Group Be Graded Motor Project is 20% of final grade (see syllabus) Performance of motor [20%] –Mostly concerned that it works –Little incentive to out-perform other groups –Must produce graphs of curves Presentation [20%] Instruction Manual [30%] Peer Evaluation [30%]

To Do List for Today Form groups of 6 (randomized) Exchange contact information Delegate responsibilities to each member Make schedule to accomplish all tasks Start constructing motor