GCSE PHYSICS - MAGNETISM AND ELECTROMAG - LESSON 14 - dc motor

How Does a Simple DC Motor Work?

Overview of the DC Motor Components

• The lesson introduces the workings of a simple DC motor, emphasizing its reliance on the motor effect.

• A schematic diagram is presented, highlighting key components such as the coil (single conducting loop) and the split ring commutator, which is crucial for motor operation.

• The split ring commutator connects to a spindle that allows rotation; it is fixed to the coil while brushes maintain contact with it.

Current Flow and Magnetic Interaction

• When the switch is closed, current flows through the coil from positive to negative, creating forces that act on it.

• Using the left-hand rule, students are guided to determine how current direction and magnetic field orientation affect spindle rotation.

• The magnetic field runs from north to south; this orientation helps in understanding force directions acting on different sides of the coil.

Rotation Mechanics

• Forces acting on either side of the loop cause it to rotate clockwise due to opposing forces generated by current flow changes.

• Without the split ring commutator, once vertical alignment is reached, further movement would cease; however, this component enables continuous rotation.

Enhancing Motor Performance

• The speed of a DC motor can be increased by:

• Increasing current flowing through the coil.

• Strengthening magnetic field intensity.

• Adding more turns in the coil.