How does an automatic watch work?
Updated
by Vaer Watches
An automatic watch, also known as a self-winding watch, is a type of mechanical watch that uses the natural motion of the wearer's wrist to power the watch's movement.
An automatic watch is one of the seven types of watches available on the market today and is the second oldest timekeeping technology in the world of horology. The seven categories by order of invention are as follows:
- Manual Watch (Mechanical) - circa 1510
- Automatic Watch (Mechanical) - circa 1923
- Quartz Watch (Battery) - circa 1969
- Digital Watch (Battery) - circa 1970
- Solar Watch (Battery) - circa 1977
- Meca-Quartz (Battery+Mechanical) - circa 1984
- Smart Watch (Battery) - circa 1998
What is the timekeeping technology used in an automatic watch?
Automatic watches, such as the Vaer A5 Tactical Field, contain a rotor that is connected to the movement's mainspring. As the wearer moves their wrist, the rotor spins, which in turn winds the mainspring. The mainspring stores the energy that powers the watch's timekeeping functions.
The watch movement consists of a balance wheel, escapement, and gear train. The balance wheel oscillates back and forth at a constant rate, and the escapement controls the movement of the gear train, which in turn moves the watch hands.
The watch also contains a series of gears that control various functions, such as the date. These functions can be adjusted by turning the watch's crown.
In summary, an automatic watch works by harnessing the kinetic energy generated by the wearer's wrist movements to wind the mainspring, which powers the watch's timekeeping functions.
What is the difference between manual and automatic watches?
The main difference between an automatic and manual wristwatch lies in how the watch movement is powered.
A manual watch, also known as a hand-wound watch, requires the wearer to manually wind the mainspring using the watch's crown. The wearer must remember to wind the watch regularly to ensure that it maintains accurate timekeeping. If the watch is not wound, it will stop working.
On the other hand, an automatic watch, does not require manual winding. The natural motion of the wearer's wrist winds the mainspring through the movement of the watch's rotor. As long as the watch is worn regularly, it will remain wound and keep accurate time. However, if the watch is not worn for an extended period, it may stop working and require manual winding to restart.
Another difference between the two types of watches is their power reserve. A manual watch typically has a shorter power reserve than an automatic watch, as it relies solely on the energy stored in the mainspring. An automatic watch, on the other hand, has a longer power reserve because it can continue to wind the mainspring as long as it is worn.
How accurate are automatic watches?
Automatic watches are generally considered to be highly accurate timepieces, with most models able to keep time within 25 seconds per day. However, the actual accuracy of an automatic watch can vary depending on a variety of factors, including the quality of the movement, the condition of the watch, and how frequently the watch is worn and wound.
When purchasing an automatic watch (including from Vaer) there is always a degree of variance between individual timepieces, which is symptomatic of the analog nature of mechanical timekeeping technology. A general rule of thumb for automatic watches is accuracy within 25 seconds per day, and most factory specs are within 30 seconds. "Chronometer" (COSC) timing, which is considered to be near-perfect accuracy, gets into the 6 seconds per day range - this is generally found on watches in the $3,000+ range.
Hear at Vaer we regulate our automatic watches to -5/+15 seconds per day.
However, even the highest-quality movements can be affected by environmental factors like temperature and humidity, which can cause the watch to run faster or slower than normal. Additionally, the accuracy of an automatic watch can decline over time if it is not properly maintained, which can lead to a loss of power and less precise timekeeping.
Overall, the accuracy of an automatic watch is generally considered to be more than sufficient for most everyday uses, but if you require highly precise timekeeping, you may want to consider a quartz watch, which are significantly more accurate than an automatic.
