The Motor Effect

• The Motor Effect

  When a current-carrying wire is put between magnetic poles, the magnetic field around the wire interacts with the magnetic field it has been placed in, causing the magnet and conductor (wire) to exert a force on each other
• To experience full force, the wire has to be at 90 degrees to the magnetic field
• If the wire runs parallel to the magnetic field, it won't experience any force at all
• At angles between parallel and 90 degrees to a magnetic field, the wire will experience some force
• The force always acts at right angles to the magnetic field of the magnets and to the direction of the current in the wire (left hand rule)
• The magnitude (strength) of the force increases with the strength of the magnetic field
• The force also increases with the amount of current passing through the conductor
• The force acting on a conductor in a magnetic field depends on:

  • magnetic flux density
  • size of the current
  • length of the conductor
• When the current is at 90 degrees to the magnetic field it is in, the force acting on it can be found using the equation: force (F) = magnetic flux density (B) x current (I) x length (L)
• Measurements:

  • force = Newtons (N)
  • Magnetic flux density = Tesla (T)
  • current = amps (A)
  • length = metres (m)