The Motor Effect

• Motor Effect


  Passing an electric current through a wire produces a magnetic field around the wire, which can exert a force on the wire when placed in a magnetic field
• Current in a Magnetic Field Experiences a Force

  1. Magnetic field around wire interacts with magnetic field it has been placed in

  2. Causes the magnet and the conductor to exert a force on each other
• Motor Effect


  Causes the wire to move
• This is an atrial view
• To experience the full force

  The wire has to be at 90° to the magnetic field
• If the wire runs parallel to the magnetic field


  It won't experience any force at all
• The force


  Acts at right angles to the magnetic field of the magnets and to the direction of the current in the wire
• Showing the direction of the force

  • Applying a current to a set of rails inside a horseshoe magnet, where a bar is placed on the rails which completes the circuit and generates a force that rolls the bar along the rails
• The magnitude (strength) of the force


  Increases with the strength of the magnetic field
• The force


  Increases with the amount of current passing through the conductor
• Force acting on a conductor in a magnetic field


  Depends on the magnetic flux density, the size of the current through the conductor, and the length of the conductor that's in the magnetic field
• Fleming's left-hand rule


  Used to find the direction of the force
• Direction of force on wire

  • Use Fleming's left-hand rule to determine direction of force