Understanding how electric motors work

• What happens to the direction of the coil when it passes through the vertical position?

  The direction changes due to the split ring commutator
• What creates a force that rotates the coil in an electric motor?

  The magnetic field from permanent magnets
• How does the motor effect relate to a magnetic field?

  The force is in a magnetic field
• What pole is on the left of the image?

  North
• What is the direction of force in the image?

  Downwards
• What is between the magnets in the image?

  A wire carrying current
• What is the main component of a DC motor that carries current and spins?

  Electromagnet
• What is the role of the brushes in an electric motor?

  • The brushes carry the electric current to the commutator, which then reverses the current in the armature coil.
• How does the magnetic field interact with the electric current in an electric motor?

  • The magnetic field interacts with the electric current in the armature coil, causing a force that makes the motor spin.
• What is the role of electric motors in fans?

  Rotate blades to circulate air
• What is the function of the brush in a DC motor?

  It maintains contact with the split-ring commutator to supply current to the armature coils
• What happens when a wire is placed perpendicular to magnetic field lines?

  A force is created that moves the wire sideways
• Why does the coil continue rotating anticlockwise?

  Due to repeated force changes
• How do electric motors function in refrigerators?

  Operate the compressor to chill food
• What does the image illustrate about the motor effect?

  • Green arrows show magnetic field direction
  • Orange wire carries current downwards
  • Upward force is indicated by the purple arrow
• What is the formula to calculate the magnetic field produced by a current carrying wire?

  $B =$$\frac{\mu_0 I}{2\pi r}$
• What occurs to the current-carrying wire when it enters the magnetic field between poles?

  It experiences an upward force
• What is the working principle of an electric motor?

  • Current flows through a coil in a magnetic field
  • Magnetic force acts on the coil (Fleming's Left-Hand Rule)
  • Commutator switches current direction at vertical position
  • Coil rotates anticlockwise due to force changes
  • Brushes maintain electrical contact during rotation
  • Cycle repeats, creating constant rotation
• What is the name of the other force shown in the image?

  Field
• What is the name of the device shown in the image?

  DC motor
• How does the direction of rotation in a DC motor work?

  • The magnetic field from the stator interacts with the magnetic field of the armature coils
  • The direction of the armature current is reversed by the split-ring commutator
  • This causes the armature to rotate in a continuous direction
• What is the motor effect?

  A force acts on a current-carrying wire
• When does the commutator switch the current direction?

  At vertical position
• How are the current and field forces related in the image?

  • The current and field forces are perpendicular to each other
  • The interaction between the current and field forces produces a motion force
• What are the key characteristics of an asynchronous electric motor shown in the graph?

  • Locked rotor torque
  • Pull up torque
  • Break down torque
  • Full load operating torque
  • Full load operating current
  • Full load operating speed
  • Slip
• How does the orientation of fingers in Fleming's Left-Hand Rule relate to the forces in an electric motor?

  It shows how magnetic field, current, and force interact
• What are some practical applications of electric motors?

  • Fans circulate air by rotating blades
  • Washing machines turn the drum during cycles
  • Refrigerators operate the compressor to chill food
  • Cars drive the wheels in electric vehicles
  • Computers power fans to cool components
• How does the coil rotate in an electric motor?

  The coil rotates in an anticlockwise direction due to the interaction between the magnetic field and the electric current
• What component is responsible for changing the direction of the coil in an electric motor?

  Split ring commutator
• What is the name of the characteristic shown in the image?

  Slip
• In what type of field does the coil operate in an electric motor?

  Magnetic field
• What rule determines the magnetic force on the coil?

  Fleming's Left-Hand Rule
• Why is a magnetic field produced when a current carrying conductor is placed between the poles of a magnet?

  The magnetic field is produced due to the interaction between the magnetic field of the magnet and the magnetic field produced by the current carrying conductor
• What do electric motors do in computers?

  Power fans to cool internal components
• How does the commutator work in an electric motor?

  The commutator reverses the current in the armature coil as it rotates, causing the motor to spin
• If the current and field forces are both increased, how would the motion force change?

  • The motion force would increase, as it is proportional to the product of the current and field forces
• How can the speed of a DC motor be controlled?

  • Varying the voltage of the DC power supply
  • Changing the strength of the magnetic field
  • Adjusting the load on the motor
• How does the torque and current of an asynchronous electric motor change with increasing speed?

  • As speed increases, torque decreases
  • As speed increases, current decreases
• How does the split ring commutator maintain continuous rotation in a DC motor?

  By reversing current direction every half-turn
• What does the thumb in Fleming's Left-Hand Rule indicate?

  The upward force on the current-carrying wire