Lesson 14: How are electromagnets useful?

• Coil of Wire: Conductive loop generating magnetic field when current flows.
• Permanent Magnets: Materials providing a constant magnetic field in motors.
• Magnetic Field (B): Region around magnets where magnetic forces act.
• Armature


  Coil of wire in an electric motor.
• Current (I)


  Flow of electric charge through the wire.
• Force on Coil: Result of interaction between magnetic fields in motor.
• Rotation of Coil: Movement caused by opposing forces on coil sides.
• Split Ring Commutator: Device reversing current direction every half turn.
• Brushes


  Carbon components allowing current flow to commutator.
• Increasing Current: Method to enhance motor speed by boosting I.
• More Turns in Coil: Adding loops increases magnetic field strength.
• Stronger Magnetic Field: Enhancing external field increases motor's rotational force.
• Reverse Current Direction

  Method to change motor's rotation direction.
• Motor Stops Spinning: Occurs when current supply to motor is cut.
• Decreasing Current Effect: Motor slows down as battery charge diminishes.
• Magnetic Field Lines: Indicate direction of magnetic forces from north to south.
• Interaction of Magnetic Fields: Results in forces causing motion in electric motors.
• Motor Components


  Includes coil, magnets, commutator, and brushes.
• Battery


  Source supplying current to electric motor.