How do motors and generators work?

Spinny thing go brr brr... and brr brr go spinny? How?

Jay - Physics Scientist

Nov 6, 2026

Agriculture and the need for electricity

Agriculture is one of the biggest sectors managed in the Philippines - making it a quintessential portion of the country's economy and livelihood keeping and sustaining millions of Filipino farmers alike.

In agricultural settings, electric motors are commonly used in irrigation pumps to draw water from wells or other water sources and distribute it to crops. They can also power farm equipment such as grain mills and other machines used for processing crops.

Generators, on the other hand, are useful in rural areas where access to electricity is limited or unreliable. For example, diesel generators use fuel to run an engine, which turns the generator and produces electricity for farm equipment, lighting, and water pumps. Although motors and generators have similar components, motors use electricity to create movement, while generators use movement to produce electricity.

Many farmers rely on common equipment to keep their farms running. Which include common farm appliances such as: electric pumps, grain mills, feed grinders, rice thrashers, corn shellers, fans, mixers and conveyors.

They run on the same principle as every other appliance - electricity. But to make electrically physically move something, we need a way to convert electrical energy into mechanical energy, but first, where do we get that electrical energy? Let's first look at what needs electricity at a common farm:

Common farm appliances

Electric Water Pump

Used to transport large amounts of water automatically

Electric Feed Grinder

Used to grind and crush corn for animal feed

Electric Corn Sheller

Removes corn kernels from cobs preparing for feed

Electric Grain Mill

Grinds rice, etc into smaller particles, like flour.

Electric Rice Thresher

Separates rice grains from stalks to make use of rice itself.

Ventillation Fan

Used to keep livestock cool by recirculating air.

Making it: Electricity and movement

Given that many of the appliances listed above operate on electrical principles, how do they move? And most importantly, how do we make the electricity that makes them move? This is where motors and generators come into place.

Motors

Generators

An electric motor converts electrical energy into mechanical energy, which allows it to produce movement or rotation.

It works through the Lorentz Force, where an electric current flowing through a wire inside a magnetic field experiences a force that causes the motor to rotate.

An electric generator converts mechanical energy into electrical energy. It works through Faradays Law of Electromagnetic Induction, which explains how moving a coil or conductor through a magnetic field changes the magnetic flux and produces an electrical voltage.

The main difference is that the Lorentz Force explains how electricity can create movement, while Faradays Law explains how movement can produce electricity. Both principles involve the relationship between electricity and magnetism, which is why they are important in understanding how motors and generators work.

For example, electric motors are commonly found in household appliances like electric fans, while generators are used to supply electricity, especially during power outages. Although they work in opposite ways, both rely on magnetic fields to convert one form of energy into another.

The structure between the two

Motors and generators have similar structural components, such as a stator, rotor, armature, and magnetic field, but each part serves a different purpose depending on the machine. The stator is the stationary part, while the rotor is the part that rotates during operation. Both machines also contain coils of wire that help produce or transfer electrical energy through magnetic fields.

Look at the image below. Can you notice the differences?

This YouTube video can help you deepen your understanding in regards to the differences between motors and generators, and how they're easily similar and even reversable!

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