What is an Automatic Watch? - in Under 500 words.
You might see the term automatic watch and wonder what it means. It is very simple. An automatic watch is a mechanical watch that winds itself. All watches are electrically powered or mechanical. Those which are electrically powered are either digital watches or are powered using a quartz-based timing mechanism. They might have moving parts, such as hands and other functions like stopwatches, but their power ultimately comes from a battery. Automatic watches are a type of mechanical watch.
How does an automatic watch work?
Mechanical watches have no batteries, they have to store all of their power in a spring called the Mainspring. As it unwinds, the power from the spring powers the watch functions. This spring has to be wound up either by hand, by turning the crown on the side of the watch or can be wound up through the movement of something else. In almost all watches this is done by a part called a Rotor, and the rotation of the Rotor winds up the mainspring. The rotor is designed to move either in both directions or back and forth between two points. Most rotors spin in both directions and charge the mainspring only when moving in one direction. They move thanks to the movement of the wrist.
Hublot Spirit of Big Bang. The square case highlights the round movement and semi-circular Rotor that powers the automatic movement.
If the watch is designed well and worn daily, then the watch will retain power almost indefinitely, as the action of wearing the watch all day will see it retain power to keep time through the night.
The amount of power a mechanical watch contains is called the power reserve, and you will often see this described in the unit of hours. A 48-hour power reserve means that when the mainspring is fully wound the watch should not stop for 2 full days.
Patek Philippe watch with Micro-Rotor powered automatic movement with a power reserve of 48 hours despite additional complications, in this case, a world timer movement.
What are the benefits of an automatic watch?
The largest benefit is that you don't have to wind it up very often if you wear it regularly. You should remember to wind it up fully if it does stop. The automatic mechanism is meant to "top up" the power not generate all the power needed to wind the mainspring fully.
There is no battery that needs replacing, however, the watch does need servicing and should be serviced at least every five years.
Many automatic watches today have a see-though case back allowing you to see the rotor. This allows manufacturers to have playful designs and very attractive rotor mechanisms related to their brand. Many people enjoy this design feature of automatic watches.
Ball Corp. Engineer Watch with large engraved Rotor and highly finished movement.
Blancpain Fifty Fathoms watch with a Seashell Rotor and highly finished movement.
Undone Watch with plain rotor and movement.
We hope that this short article helps you understand what an automatic watch is. The Watch Collectors' Club exists to help you learn more about watches, from the basics to the finest complications. We run regular watch events where people share their knowledge and stories, and you can find more details on our website. Please follow us on Social Media for all future details.