1. 1.Have out your electric motor project. 2.Who was the first person to successfully create an electric motor? 3.What was this man’s profession? 4.What did he discover? U3e-L16 April 9, 2008 DRILL Michael Faraday Physicist and Chemist Electric currents create a magnetic field and magnetic fields induce electric currents.

2. U3e-L16 Electric motors are used everyday in many ways. A motor’s purpose is to turn electrical energy into mechanical energy. Motors work on simple principles of magnetism: Opposite poles _____________ Like poles _____________ ELECTRIC MOTORS NSNS ATTRACT REPEL NS

3. An electric current produces a magnetic field. Electric current through a coil of wire creates an electromagnet. What is the benefit of creating a magnet with electricity? –It can be turned on and off. –The strength and direction of the magnetic poles can be controlled by altering the strength and direction of the electric current. ELECTRIC MOTORS U3e-L16

4. NSNS ELECTRIC MOTORS Back to our magnet: Suppose we create an electromagnet like below. What will happen? –The electromagnet and the permanent magnet will REPEL each other. What will happen now? –The electromagnet and the permanent magnet will ATTRACT each other.

5. NS NS What would happen if we put an axle through the middle of the permanent magnet, then turned on the electromagnet? This is how a motor rotates. The electromagnet is turned on and off so that the permanent magnet is attracted, then repelled, then attracted, then repelled….and so on. ELECTRIC MOTORS U3e-L16

6. Let’s look at your electric motor project Identify the following: –Permanent Magnets –Electromagnet How is the electromagnet powered? What is the circuit that the current must follow? If your motor were working ideally, how is the electromagnet turned on and off to cause CONSTANT rotation? ELECTRIC MOTORS U3e-L16

7. The commutator turns the electromagnet on and off at particular times. When does it turn the magnet on? When does it turn the magnet off? ELECTRIC MOTORS

8. What is a schematic? How would a schematic of your electric motor look? ELECTRIC MOTORS A schematic is a diagram that represents the elements of a system without using realistic pictures. V = 9V I Load Switch = Commutator U3e-L16

9. Now that you know what switches look like in electrical schematics, draw an electrical schematic for a lamp plugged into a wall outlet. Remember that AC power supplies look like in electrical schematics. ELECTRIC MOTORS U3e-L16

10. ELECTRIC MOTORS 120 V Lamp U3e-L16

11. HOMEWORK Tomorrow is a review for Monday’s test on Electrical Technology. Begin studying tonight! Any problem/question that you’ve seen in class is a candidate for the test. Come to class with any questions you may have. U3e-L16