What is a Seiko Automatic watch?
A Seiko Automatic watch is not the same as a Seiko Kinetic watch. A Seiko Automatic is a mechanical wristwatch with a self-winding mechanism. In other words, one does not have to wind the crown periodically to keep the watch running. A manual or manual wind watch must be wound by hand, using the crown, usually every day, to operate continuously.
All self-winding watches work on the principle of converting arm motion (kinetic energy) into the winding of the mainspring (potential energy). Usually, this is performed by a half-disc of metal weighted at the edge called a rotor, which spins when the wearers arm is accelerated unpredictably (that is, when moved normally in the course of everyday life). This rotary motion is then geared down to wind the central arbor of the mainspring.
All
Seiko Automatic watches have an overwind protection mechanism of one
sort or another, to prevent breaking the mainspring once fully wound.
In a typical system, the mainspring, which is wound at the central
arbor of the barrel, is not rigidly attached to the outside of the
barrel. Instead, there are a series of detents along the outer edge of
the barrel that allow a stiffly constructed mainspring part called the
bridle to slide along when an attempt to overwind is made. On some
watches, a faint click can be heard when this happens, on others, it
cannot be heard.
It
should be noted that this overwind protection is critical to avoid
damage to the watch, and is reported to be one of the more tricky
things to get right during a watch service because of the special
lubricant needed to ensure proper operation.