Power reserve
From Wikipedia, the free encyclopedia
Power Reserve Indicator - originally called French: Réserve de Marche - is a function of the watch, which is meant to show how long the watch is going to work until the next winding. In its essence, the power reserve indicator shows how tense the mainspring is at the moment.
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[edit] Functioning
The indication of the power reserve is represented through a needle. The needle moves from one point of the indicator to another. The zone along which the needle moves, shows how much time is left till the mechanism stops, and when the needle leaves the zone the watch needs to be wound. The indicator itself represents the amount of tension of the mainspring, thus the lower is the tension the less time is left until another winding of the watch.
[edit] Overview
The power reserve indicator is one of the most important features of a mechanical watch. The latter has either automatic or manual winding. In order to run at a regular rate a mechanical timepiece needs to have at least 30 per cent of its mainspring wound. An automatic timepiece needs to be worn for about 10-15 hours until it is fully wound.
The power reserve indicator displayed at the watch with automatic movement shows how much time a watch will function when not worn. The one displayed at a watch with the manual winding mechanism shows the time left for its next winding.
[edit] Brief History
Power reserve indicators were first used on marine chronometers and then later used on high grade pocket watches. The first wristwatch with one was created by Breguet in 1933. However there was only one copy of this watch assembled. Later in 1948, Jaeger-LeCoultre introduced a power reserve indicator which was designed for production series of the company's Powermatic. Thus Jaeger-LeCoultre was the first watchmaking company to launch wristwatches with a power reserve indicator to the masses.
[edit] External links
Categories: Watches | Clocks | Horology
