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Magnetism From Electricity

Magnetism From Electricity. What electromagnets are and how they are important to our daily lives. What is a Maglev Train?. A train with no wheels Floats on a cushion of air Suspended by same-poled magnetic fields generated by a series of electro-magnets through the rail & the train.

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Magnetism From Electricity

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  1. Magnetism From Electricity What electromagnets are and how they are important to our daily lives.

  2. What is a Maglev Train? • A train with no wheels • Floats on a cushion of air • Suspended by same-poled magnetic fields generated by a series of electro-magnets through the rail & the train

  3. Who is responsible for the discovery of Electromagnetism? • Hans Christian Oersted • Found that a compass was affected by a nearby electrified wire • The compass needle moved differently depending on which direction the electricity flowed

  4. What is Electromagnetism? • The interaction between magnets and electricity • Are useful for a large number of applications • Can be controlled and manipulated

  5. ….more on electromagnetism. • By itself, the magnetic field caused by electricity, is actually not strong enough to be very useful • However electromagnets and solenoids can strengthen the magnetic field

  6. What is a Solenoid? • A coil of wire that produces a magnetic field when electric current passes through it • The more loops = the stronger the magnetic field • The magnetic field is very similar to a bar magnet’s magnetic field Also the magnetic field increases with increased current

  7. What is an Electromagnet? • Made up of a solenoid wrapped around an iron core • The magnetic field (MF) aligns the domains in the iron core • The MF is the combined MF of the coil and iron core

  8. Can electromagnets be made stronger? • Yes, by increasing the number of loops per meter (or per centimeter) in the solenoid • Increasing the number of loops around the iron core • Remember Maglev trains?

  9. Can electromagnets be turned off and on? • Think about the practical applications of being able to start & stop magnetism • A junk yard uses a huge electromagnet to pick up & drop tons of material!

  10. What are some other practical uses of electromagnets? • Doorbells • Electric locks • Circuit breakers • MRI machines • Magnetic Resonance Imaging • Speakers of any size • And many more

  11. What is the relationship between magnetic force & electric current? • If a current-carrying wire can cause a magnet to move… • Then a magnet can cause a current-carrying wire to move • This property is important in how electric motors work

  12. What are electric motors? • A device that changes electrical energy into mechanical energy • All electric motors have …. • Armature - a loop or coil of wire that rotates • Armature is mounted between the poles of a permanent magnet & electromagnet • Can use Direct Current (DC) - electricity moving in one direction • Can use Alternating Current (AC) - electricity moving in two directions

  13. A Direct Current (DC) Electric Motor

  14. A Direct Current (DC) Electric Motorcont…

  15. What is a Galvanometer? • Measures current • Can detect direction of current • Useful in detecting electrical polarity • Electricians use instruments like this daily

  16. Be sure to check the wikispace for more information, a copy of this PowerPoint & website’s that show details of electric motors https://nemsgoldeneagles.wikispaces.com/

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