Magnetism: Electric Motors

An electric motor is a mechanical device that transforms electrical energy into rotational kinetic energy. It operates using the interaction between magnetic and electric fields.
The basic components of an electric motor include: a split-ring commutator, a coil of wire, two magnets, and brushes that maintain electrical contact with the commutator.
When current flows through the coil of wire, it produces a magnetic field. This interacts with the other magnetic field set in place by the magnets, resulting in a force.
This force causes the coil of wire to spin. The direction of this force is determined by Fleming’s Left-Hand Rule, which states that the thumb presents motion (Force), the first finger presents field (Magnetic), and the second finger presents current.
The commutator is a crucial component because it alternates the current as the coil spins, ensuring that the coil continues to spin in the same direction even after passing the line of equilibrium. This is different from an alternator, where the direction of current is not altered.
The brushes maintain contact with the commutator, allowing the current to continue flowing through the coil.
The rotational kinetic energy generated by the motor can then be utilised in various ways, depending on the function of the device the motor is attached to.
The speed of an electric motor can be controlled by altering the current flowing through the coil or changing the strength of the magnetic field.
There are several types of electric motors, including direct current (DC) motors and alternating current (AC) motors, each of which functions slightly differently and are suitable for different applications.
Electric motors are found in many everyday objects, including washing machines, electric vehicles, fans, drills, and more, rendering a deep understanding of how they operate important in applied Physics.