Motor Effect

• Motor effect: A current carrying wire in the presence of a magnetic field will experience a force
• The wire needs to be at exactly 90 degrees to the magnetic field to experience the full force
• To find the direction of the force, we need to know the direction of the magnetic field and the direction of the current in the wire
• Fleming's left-hand rule is used to determine the direction of the force:

  • Thumb points up (force)
  • First finger points forwards (magnetic field)
  • Second finger points out to the side (current direction)
• In the scenario of a horseshoe magnet with three metal rails, the force direction can be found using Fleming's left-hand rule
• To calculate the strength of the force when the wire is at a right angle to the magnetic field, use the equation:

  F = B * I * L (Force = Magnetic flux density * Current * Length)
• Example calculation:

  • 10 cm wire (0.1 meters), 5 amp current, 0.4 teslas magnetic flux density
  • Plug values into the equation: 0.4 * 5 * 0.1 = 0.2 newtons