Magnetism Class Notes

• What are the 3 elements in ferromagnetic materials?

  iron, nickel and cobalt
• What are the 2 subclassifications of materials affected by magnetism?

  -paramagnetic - likes magnetism (small attraction)

  -diamagnetic - opposes magnetism
• What are the 3 laws of magnetism?

  1. like poles repel, unlike poles attract each other
  2. energy is required to create a magnet, but no energy is required to maintain it
  3. the force b/w 2 magnetic poles is directly proportional to the product of the strength of the 2 poles and inversely proportional to the square of the distance b/w them
• What is another way to destroy magnets? (other than vibration, heating or placing it in an AC coil/using current)

  Not placing a keeper on it
• What is another way to create magnets other than stroking a piece of ferromagnetic material with a magnet, aligning with earth's magnetic field and tapping, and placing it in an energized DC field/using current?

  magnetic induction
• What are typical permanent magnets made of?

  Alnicos (Aluminum, nickel, cobalt and iron)
• Why are some conductors attracted to each other in a magnetic CCT?

  Magnetic coupling
• All electrical generation equipment (DC generator or AC alternator) makes AC internally
• A commutator mechanically forces current in one direction (rectified AC to DC)
• Slip rings make each pole a north or south
• Flux density can be adjusted with excitation current via rheostat