Electromagnetism : Motor Effect

Question 1

What is MOTOR EFFECT ?

Answer 1

The motor effect occurs when a current-carrying wire is placed in a magnetic field, causing the wire to experience a force. This effect results from the interaction of the magnetic field produced by the current in the wire and the external magnetic field into which the wire is placed.

Question 2

What happens when no current flows THROUGH a wire in a magnetic field?

Answer 2

When no current flows through a wire placed in a magnetic field, the wire EXPERINCE NO FORCE because there is no interaction between the magnetic fields

Question 3

How does a simple DC MOTOR WORK?

Answer 3

• A simple DC motor consists of a coil of wire placed in a uniform magnetic field.
• When current flows through the coil, it creates a magnetic field that interacts with the external magnetic field, producing forces on opposite sides of the coil.
• These forces cause the coil to rotate.
• The split ring commutator ensures that the current direction in the coil reverses after each half turn, maintaining continuous rotation.

Question 4

How can the direction of rotation in a DC motor be REVERSED?

Answer 4

The direction of rotation in a DC motor can be reversed by either:

• Reversing the direction of the current,
  or
• Reversing the poles of the magnetic field.

Question 5

What is FLEMING’S LEFT HAND RULE, and how is it applied in the context of a motor?

Answer 5

Fleming’s Left-Hand Rule helps determine the direction of the force on a current-carrying conductor in a magnetic field. It states that:

• The First finger points in the direction of the magnetic Field.
• The seCond finger points in the direction of the Current.
• The THumb points in the direction of the thurst (the force).

By applying this rule to each side of the coil in a DC motor, you can determine the direction of the forces, which should be in opposite directions to cause rotation.

Question 6

What causes the coil in a DC motor to CONTINUE ROTATING even when no current is flowing?