Interesting facts about watches
Power reserve and precision in automatic watches
Switching from a battery-operated quartz watch to an automatic timepiece will need a little getting used to. All first-time owners share this experience. We have put together all the interesting facts and practical handling tips you need to know to make the transition as easy as possible.
Power reserve
The mainspring is not fully wound until it has been wound manually using the crown (approx. 30-40 rotations) or the watch has been moved for a longer period. Any stoppage reduces the power reserve. An automatic watch can only be kept motionless for approximately 2-5 hours. We advise winding the watch completely before putting it on your wrist. Unlike hand-wound watches, this procedure cannot damage an automatic watch.
Precision
The precision of automatic watches is dependent on a large number of factors: temperature, air pressure and the manner in which it is worn all determine the precision of an automatic watch. Magnetic fields, for instance those emitted by electric motors, loudspeakers and door closers, can endanger precision. In contrast, the Earth’s magnetic field does not impact negatively on the precision.
A watch’s precision values are always measured in a variety of positions and across several days, based on a period of 24 hours. These values are then taken to determine absolute precision. A precision deviation of -4 to +6 seconds per day is an excellent value, although only very few and high-quality automatic movements achieve equivalent results (C.O.S.C. – Contrôle officiel suisse des chronomètres). In general, a ‘normal’ deviation in precision is between -10 and +45 seconds per day.
Tip: If you happen to be dissatisfied with the position of your watch, you can attempt to keep it in a variety of positions during the night. Place the watch alternately on its front and its back, or upright on the crown side and then on the other side. This alters the attitude of the balance wheel, and therefore impacts positively on the watch precision.
