Power reserve indicator

Clock with power reserve indicator on the right

The power reserve indicator shows the remaining time until a mechanical watch comes to a standstill and thus provides information on whether or when the watch needs to be rewound, for example using a winding crown . The power reserve or power duration is the time that a watch runs after being wound until it has to be rewound.

In the case of mains-operated clocks (for example in time switches), a power reserve is a clockwork that is independent of the mains or a battery-operated emergency power supply for the clockwork.

origin

This form of display was originally developed for marine chronometers (also called up and down). The aim was to ensure the accuracy of the clock required to determine the geographical longitude by specifically winding it up with the same remaining power reserve, since in particular the almost completely tensioned or relaxed spring can lead to inaccuracies.

Various paths have been taken to achieve technical feasibility. Abraham Louis Breguet prevailed around 1800 with his design of a screw differential.

In the case of wristwatches , a power reserve indicator on the dial was first implemented in a watch from the Breguet manufacture in 1933 . In the 1950s, many automatic calibers were equipped with this indication. Due to the technical complexity, power reserve displays on wristwatches were originally only available in the upper price range. Around 1990 power reserve displays found increased (fashionable) interest again.

In the case of watches with an automatic winding mechanism , power reserve indicators were first installed to signal to the wearer that the automatic mechanism was working and had generated sufficient potential energy . The efficiency of automatic watches with a pendulum flywheel and unidirectional winding rotors was lower due to the unused 360 ° in both directions. The power reserve indicator makes it possible to avoid the watch stopping by manually winding it up. Nowadays, power reserve indicators are often used for aesthetic reasons as well.

literature

Anton Kreuzer: wristwatches. Watchmaking masterpieces. From the cylinder clock to the Grande Complication. A standard work for collectors and watch enthusiasts. Nikol, Hamburg 1998, ISBN 3-933203-10-4 .

Web links

Treatise of the Gesellschaft der Uhrenfreunde e. V. via power reserve displays

Remarks

↑ CHRONOS - Gesellschaft der Uhrenfreunde eV, power reserve display - a technical challenge
^ Helmut Kahlert , Richard Mühe , Gisbert L. Brunner , Christian Pfeiffer-Belli: wrist watches: 100 years of development history. Callwey, Munich 1983; 5th edition, ibid 1996, ISBN 3-7667-1241-1 , p. 504.
↑ See also Adolf Benz: The importance of a lockable mass in the automatic winding of a wristwatch with a power reserve display. In: Chronometrophilia. No. 25, 1988, pp. 87-90.

[1] CHRONOS - Gesellschaft der Uhrenfreunde eV, power reserve display - a technical challenge

[2] Helmut Kahlert , Richard Mühe , Gisbert L. Brunner , Christian Pfeiffer-Belli: wrist watches: 100 years of development history. Callwey, Munich 1983; 5th edition, ibid 1996, ISBN 3-7667-1241-1 , p. 504.

[3] See also Adolf Benz: The importance of a lockable mass in the automatic winding of a wristwatch with a power reserve display. In: Chronometrophilia. No. 25, 1988, pp. 87-90.