1 / 11

Chapter 22: Induction and Alternating Current

Chapter 22: Induction and Alternating Current. pp 793 - 820. Essential Questions. How can current be produced without a power source? How do motors work? How is mechanical energy converted to electrical energy?. Objective(s ): We will be able to….

zohar
Download Presentation

Chapter 22: Induction and Alternating Current

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 22: Induction and Alternating Current pp 793 - 820

  2. Essential Questions • How can current be produced without a power source? • How do motors work? • How is mechanical energy converted to electrical energy?

  3. Objective(s): We will be able to… • Describe how a magnetic field can induce current in a wire. • Describe how an electric motor relates to an electric generator.

  4. Agenda: • Sorry, no building motors today due to technical difficulties! Tomorrow instead. • Check and review Magnets homework. • Intro to Inductance: • Notes: • Magnetic Fields and Induced EMFs • Generators • Motors

  5. Electromagnetic Induction • Current in a circuit can be induced without the use of a battery or voltage source. • We know that magnets cause electrons to move and realign, sooo… • If a magnet moves closer to a circuit… • Or a circuit is moved closer to a magnet… • If there is any relative motion between a circuit and a magnet, current is induced in the circuit.

  6. Electromagnetic Induction • The angle between the magnetic field and the circuit affects induction. • (The blue dots are magnetic field lines coming out of the page) • The closer to perpendicular the magnetic field is to the circuit, the more current is induced. • The greater the amount of magnetic field lines (the strong the magnetic field), the greater the current induced. Not surprisingly.

  7. Generators • As we learned before, generators convert mechanical energy into electrical energy. • For example, a hydroelectric plant converts falling water into rotational motion (like using a water wheel). • This rotational motion turns a wire loop in a magnetic field, inducing an emf.

  8. Generators • Generators produce a constantly changing emf, due to the angle between the magnetic field and the wire (circuit) constantly changing. • This is what produces alternating current. • The frequency of rotation of the coil determines the frequency of the sign change of the emf.

  9. Motors • Motors are devices that convert electrical energy to mechanical energy. • Like generators in reverse: • A current is run through a wire coil connected to a rotating shaft. • As that wire rotates, it will be alternately attracted and repelled by any magnet in its vicinity.

  10. Recap • Any relative motion between a magnet and a circuit induces a current in that circuit. • The induced emf is greatest when the magnetic field is perpendicular to the circuit. • Generators convert mechanical energy to rotational motion, rotating a wire coil in a magnetic field. • Motors convert electrical energy to mechanical, using a magnet to repel and attract a wire coil repeatedly.

  11. Homework • Due Friday: • p802 #2 • p 821 #5, 15, 16, 22

More Related