Electric motor

Magnet Electric motor Electric motors use magnetism to produce movement. Today, they are the driving force behind many everyday devices. Getting the modern world MOVING

The electrified wire becomes magnetized, so it swings around the magnet in a circle.

Bowl of mercury

Faraday’s electrical experiments

English scientist Michael Faraday made the first electric motor in 1821 when he produced conTinuous moTion from electricity. It worked because passing an electric current through a wire produces magnetism. Later motors used electromagnets—coils of wire around an iron core—to make this effect stronger.

Motoring on

German engineer moriTz Von Jacobi used electromagnets to make a motor powerful enough to be put to practical use. In a world first, an improved version of his motor drove a paddleboat across the Neva River in Russia in 1838 with 14 people on board.

It couldn’t have happened without…

In 1820, HAns Oersted discovered electrOMAgnetisM— he found that an electric current could create a magnetic field. Nikola Tesla was an American engineer who worked on a large number of different inventions during his lifetime.

By the way... I once started a small but alarming earthquake in the course of one of my experiments, and another time made terrifying artificial lightning!

The wire is coiled into eight electromagnets. Passing a current through the wire makes the central wheels turn.

Electric current provided by a battery travels through the wire.

Also in 1820, André-MArie AMpère worked out the relationship between the electromagnetic force and the electric current.

An outer set of electromagnets (called the stator) remains stationary.

Inside the stator, a moving set of electromagnets forms the rotor.

HOW Motors that run on direct current have a permanent IT WO R KS magnet and an electromagnetic rotor. The rotor’s north and south poles are attracted to the opposite poles of the permanent magnet, so the rotor moves half a turn. The direction of the current is then reversed, so the rotor moves another half-turn. Continually switching the current like this keeps the motor spinning. Motors that use AC work in a similar way, but they do not need a mechanism to reverse the current.

Permanent magnet

South

Rotor

North

Tesla’s induction motor

The rotor can be attached to machinery, such as a fan or a conveyor belt. A split ring called a commutator switches the current’s direction. Reversing the current reverses the rotor’s magnetic poles, making it move half a turn.

Nikola Tesla invented the electric motors that power large machines today. His induction motor, invented in 1887, runs on alternating current (AC)—electric current that changes direction many times a second—rather than the direct current (DC) provided by a battery.

How it changed

Electric motors took over from clunky steam engines to power machines. Now they also power the appliances we plug in and switch on every day.

It paved the way for... the world

Steam-powered washing machines were laundering clothes in the 1800s, but electric motors made them smaller and more convenient. electric cars were first invented in the 19th century, but only now do they look set to rival gas-powered ones.