Magnetism and Electromagnestism

Magnetism and Electromagnestism

1. Properties of Magnetic Materials

   • Magnetic Materials
     • Ferromagnetic Materials
       • Easily Magnetized
       • Nickel, Iron, Cobalt, Manganese
     • Paramagnetic Materials
       • Can be magnetized but not easily
       • Platinum, Titanium, Chromium
     • Diamegnetic Materials
       • Cannot be magnetized
       • Lines of force go around
       • Copper, Brass, Antimony
   • Classification
     • Temporary
       • Domains only aligned when force applied
         • Force= another magnet or electric current
         • Force removed little to no magnetic effect
     • Permanent
       • Always have magnetic effect
       • Alloy Steel often used
   • Magnetic Poles
     • North Pole
       • Attracted to geographic North
     • South Pole
       • Attracted to geographic south
     • Field flows N to S
     • Like poles repel, opposite attract

2. Magnetism Terminology

   • Magnetic Flux
   • Flux Density
   • Permeability
   • Reluctance
   • Retentivity
   • Saturation

3. Electromagnetism

   • Magnetic Feild Direction
     • Left Hand Rule for Conductors
   • Magnetic Coil Polarity
     • Left Hand Rule for Coils
   • Factors Effecting Electromagnet Strength
     • Current
     • Turns
     • Type of Core
   • Hysteresis Loss, Eddy Currents, and Core Saturation
     • Hysteresis loss: Silicon Steel
     • Eddy Currents: Thin insulated sheets
     • Core saturation: domains are aligned

4. Induced Voltage

   • Faraday's Law of Induction
   • Fleming's Left-Hand Rule
   • Factors Affecting Induced Voltage
     • Flux Density
     • # of turns
     • Velocity and angle of cut

5. Electromagnetic Induction

   • Self-Induction
     • Change in current causes change in magnetic field inducing a voltage
     • Induced voltage opposes current
   • Lenz's Law of Induction
     • If an induced current flows, its direction is always such that it will oppose the change which produced it.
   • Inductance
     • Property that opposes change of current
   • Mutual Induction

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