Electric motor

An electric motor turns power into movement.

It has two main parts. One part is called a rotor. It is the part that moves. The other part is the stator. It stays still.

Inside, magnets create a force. This force makes the rotor spin. The motor can power many things. It can run a big fan. It can even be in a watch.

These motors help our world work.

An electric motor turns electricity into movement.

It is a machine that changes electrical power into mechanical power. Most motors work using magnets and electric current.

A motor has two main parts. The first part is the stator. The stator stays still. The second part is the rotor. The rotor is the part that moves.

Inside, the stator uses magnets to make a magnetic field. This field passes through the rotor. The rotor has coils of wire called an armature. When electricity flows through these wires, the magnetic field pushes them. This push creates a force that turns the rotor's shaft.

Some motors use a commutator to work well. A commutator is a special switch that rotates.

It uses small parts called brushes to send electricity to the rotor. The commutator flips the direction of the current. This keeps the rotor turning in one direction.

We use motors everywhere. They power large fans and big pumps. They also run tools and even electric cars. Some motors are very small. You might find them inside an electric watch.

An electric motor is a clever machine. It changes electrical energy into mechanical energy. This means it takes electricity and turns it into movement. Most motors work because of how magnetic fields and electric currents interact. This interaction creates a force called torque on the motor's shaft.

This torque is what makes the motor spin or move. Motors can be used to push things or rotate them. They are a type of device called an actuator.

Inside the motor, two main parts work together. One part is the stator, which stays still. The other part is the rotor, which moves. The stator usually holds magnets to create a magnetic field. The rotor has wire windings called an armature.

When electric current flows through the armature, the magnetic field exerts a force on it. This force is called the Lorentz force. It pushes the rotor and makes it turn. There is also a tiny air gap between these parts. This gap must be small to work well, but not too small.

Some motors use a special part called a commutator. A commutator is a rotary electrical switch. It helps supply current to the rotor as it spins. It uses small parts called brushes that press against it.

These brushes make contact with different segments of the commutator. The commutator reverses the current direction every half turn. This keeps the torque pushing in the same direction. Without this, the rotor would just stop moving.

People have been studying motors for a long time. In 1821, Michael Faraday showed how electricity could cause rotation. He used a wire in a pool of mercury near a magnet.

Later, Ányos Jedlik built a motor in 1828 with a stator and rotor. In 1832, William Sturgeon invented the first commutator. Thomas and Emily Davenport used these to power printing presses in 1837. By 1834, Moritz von Jacobi made a very powerful motor. His motor was strong enough to drive an electric boat.

We see electric motors in almost everything today. They power huge machines like marine propulsion systems. Some very large motors have an output over 100 megawatts. You can find smaller motors in household appliances and power tools. They even run the disk drives in computers. Some motors are very tiny and live in electric watches.

Some motors can even work in reverse. In electric vehicles, they can act as generators. This helps recover energy that might be lost as heat. This process is called regenerative braking.

An electric motor is a sophisticated machine designed to convert electrical energy into mechanical energy. This conversion process allows electricity to perform physical work, such as spinning a shaft or moving a component. Most motors operate through the interaction between a magnetic field and an electric current. This interaction generates a force known as Laplace force, which creates torque on the motor's shaft.

Because they produce linear or rotary force to move an external mechanism, motors are classified as a type of actuator. While they are usually designed for continuous rotation, they can also be used for linear movement over significant distances.

To understand how a motor works, one must look at its two primary mechanical components: the rotor and the stator. The rotor is the part that moves to deliver mechanical power. The stator is the part that remains stationary and surrounds the rotor.

Electrically, the motor functions through a magnetic circuit consisting of field magnets and an armature. The field magnets, which can be permanent magnets or electromagnets, are typically located on the stator. The armature, which consists of wire windings on a ferromagnetic core, is usually attached to the rotor. When electric current passes through the armature windings, the magnetic field from the stator exerts a Lorentz force on the wires. This force causes the rotor to turn.

Engineers carefully manage the physical construction of these parts to ensure efficiency. A small air gap is maintained between the stator and the rotor to allow movement. This gap must be kept as small as possible because a large gap weakens the motor's performance. However, if the gap is too small, it may cause noise or friction. The stator core is often built from many thin metal sheets called laminations. These laminations are made of electrical steel and are insulated from each other. This design reduces energy losses caused by induced circulating eddy currents that would occur in a solid core.

In some motors, such as those used in washing machines, the stator is encapsulated in plastic resin to prevent corrosion or noise.

In many direct-current (DC) motors, a specific component called a commutator is required. The commutator is a rotary electrical switch that supplies current to the rotor. It consists of a cylinder made of multiple metal contact segments. To deliver electricity, two or more conductive brushes, often made of carbon, press against the commutator.

As the shaft rotates, the brushes make sliding contact with successive segments. The commutator is essential because it periodically reverses the direction of the current in the rotor windings every 180 degrees. This reversal ensures that the torque is always applied in the same direction. Without this mechanism, the direction of the torque would reverse every half turn, causing the rotor to stop.

There are several ways to classify motors based on their design and motion. Motors can be powered by direct current (DC) from batteries or alternating current (AC) from a power grid. They can also be categorized by their construction, such as being brushed or brushless. Some motors use a salient-pole configuration, where the cores have projections called poles that face each other. Others use a nonsalient-pole design, where the core is a smooth cylinder with windings distributed in slots.

Motors may also be cooled by air or by liquid depending on their intended use.

The history of the electric motor is a timeline of many scientific discoveries. Early experiments in the 1740s involved electrostatic motors, which relied on electrostatic force. These were difficult to use because they required very high voltages. In 1820, Hans Christian Ørsted discovered that electric current creates a magnetic field. This led Michael Faraday to provide the first demonstration of rotary motion in 1821. He used a wire dipping into a pool of mercury near a permanent magnet.

Later, in 1827, Ányos Jedlik invented the commutator, which allowed for continuous rotation. By 1834, Moritz von Jacobi created a powerful motor capable of driving an electric boat.

Today, electric motors are vital to modern civilization and appear in many different scales. Large-scale motors are used for marine propulsion and pipeline compression, with outputs exceeding 100 megawatts.

On a much smaller scale, tiny motors can be found inside electric watches.

Motors also power household appliances, power tools, and vehicles. Interestingly, some motors can operate in reverse to act as generators. In systems like regenerative braking in vehicles, the motor converts mechanical energy back into electrical energy. This process recovers energy that would otherwise be lost as heat and friction.