The motor effect

• what is the motor effect?

  When a current carrying conductor passes through magnetic field at right angles, it experiences a force
• what do we use to predict the direction of force?

  Fleming's Left-Hand Rule.

  
• how can we increase the force?

  Increase the current.

  Use a stronger magnet.
• How can we change the direction of the force?

  Reverse the current.

  Swap the N and S poles around.
• How do you create a faster motor?

  More current.

  Stronger magnet.

  More coils on the motor.
• Split ring commutator


  Changes the direction of the current every half turn.
• Carbon brushes

  Connects the battery to the coil.
• The energy transfer in a DC motor are:

  Electrical energy to Kinetic energy.
• In Fleming's left hand rule the Thumb represents what?

  Force.
• In Fleming's left hand rule the First Finger represents what?


  Magnetic Field.
• In Fleming's left hand rule the Second Finger represents what?

  Conventional Current.
• Conventional Current.

  From positive to negative.
• The current around a single wire has which pattern?

  Concentric circles.
• When a current flows through a wire a magnetic field is produced around it
• The force can be increased by increasing the current or by increasing the strength of the magnetic field
• The force is greatest when the wire is perpendicular to the magnetic field
• It is zero when the wire is Parallel to the magnetic field lines
• The direction of the fore is always at right angles to the wire and The magnetic field lines and the direction is reversed if the c or mg is reversed
• In an electric speaker, you can control the speed of an electric current and reverse its turning direction by reversing the current
• The coil spins because q force acts on each side of the coil due to the motor effect and the force on one side is is in the opposite d of the force on the other
• The split ring commutator reverses the current round the coil every half turn of the coil, meaning the coil is pushed in the same direction every 1/2 turn
• In a loudspeaker, a coil vibrates when alternating current passes through the coil
• Each time the current changes its direction the force reverses its direction
• As it is constantly forced back and forth, the motion Makes the diaphragm vibrate so loudly so sound waves are created
• Use the left hand rule to predict the movement of the wire


  Wire moves out of the page

  
• Which side of the coil experiences a force into the screen?

  B

  
• Which side of the coil experiences a force out of the screen?

  D

  
• Which side experiences no force?

  C