Minute by minute watch hands are moving around the dial, accurately measuring a specified period within specified time. What is powering them? In modern watches two types of energy sources can be applied: battery and spring. And according to the energy source type watches are divided into two categories: quartz and mechanical.
In mechanical watches the movement is activated by the spring. During winding the spring is twisted around the reel. And untwisting the spring activates toothed gearing of the movement which in its turn moves hands. When the spring is fully untwisted, the watch stops, and to set it to operation you should wind the spring again.
Many watch manufacturers are looking for ways of increasing the power reserve of mechanical watches. Using new materials and creating new alloys, they make long and tight springs, experimenting with their shape. And increasing the size of the case (it’s good that there is such a trend nowadays), watch companies set additional reels inside. The more reels, the longer the springs, the greater the amount of energy and, therefore, the watch goes longer.
But the task is far more difficult than it might seem at first sight. The problem is that while the spring unwinds its speed varies. Because of this, here appears a stroke error: the watch gets slow or fast. The larger is the reel and the longer is the spring, the bigger is the error. There is no universal means to compensate the error. That is why most modern mechanical watches have an average 40-hour power reserve. Owing to this the error is not significant and meets a formally permissible value from +40 to -20 seconds per day.
But, following different ways, elite manufactories still find the means to increase the duty of their models and compensate the error. Such brands as Patek Philippe, IWC, Audemars Piguet, Blancpain, Officine Panerai, Jaeger-LeCoultre, have in their arsenals calibres with a power reserve of 7-10 days. And the leader of watchmaking A. Lange & Sohne has a wonderful calibre L034.1 with a month’s power reserve. This mechanism has not only two reels, but also two springs – main and auxiliary which stabilizes the rotation of the first one.
The most common and practical means of keeping the mechanical watch going is a self-winding movement. It has become a significant part of watchmaking and now most models of Swiss and other brands’ watches are fitted up with the self-winding movement.
The device is an additional mechanism that winds the spring during vibration of the watch: due to inertia. For example, these can be hand movements when walking or gesticulating. If the wearer leads active life, a spring in the watch is kept in a stable condition: it is wound and unwound at the same speed. It has a positive affect not just on power reserve, but also on the precision.
Self-winding watches also have some disadvantages. Due to the presence of extra mechanism they are typically thicker and heavier than watches without this feature. Because of this women's wrist watches are not so often equipped with a self-winding movement. The self-winding movement is also difficult and expensive to repair in case of breakdown. In most cases of this mechanism being damaged, when the repairing is fulfilled by watchmakers uncertified by the brand, the mechanism is simply taken out. But the most important message is it won’t be useful if you have a sedentary lifestyle or wear the watch occasionally.
For storage of self-winding watches special boxes – time movers – are designed. They are equipped with a mechanism that moves the watch kept inside, so that they are constantly being wound. This is convenient not only for the owner who can wear the watch being wound at any time. It is also very good for the movement: in working condition the watch will better preserve accuracy for a long time.
Collectors keep their watches in large boxes with automatic winding. They are sometimes designed for even a few dozen items. For expensive Swiss watches fine boxes of precious materials are created. They are luxury items themselves (for example, the boxes by Buben & Zorweg).
Quartz watches are arranged quite differently. Instead of complex and sophisticated spring mechanism they have an ordinary (or solar) battery as the source of energy. And uniform oscillations are produced by the generator based on a quartz crystal. This generator transmits pulses to the stepping electric motor which, in its turn, actuates a mechanism of wheels and hands.
Unlike mechanical watches, quartz ones can have a digital display instead of the dial with hands. Watches with such a display are called electronic.
Electronics has its advantages over mechanics. First, quartz watches do not require regular winding. They can be worn irregularly, from time to time, and there is no necessity in caring about their storage.
Secondly, the oscillation frequency of the generator is more stable than that of the spring reel. The accuracy error of quartz watches is only from +20 to -20 seconds per month.
However, the battery is to be changed periodically. And quartz crystal ages with time, and due to this the watch gets fast. That’s why in the long-term perspective mechanical watches are considered more reliable in terms of the service life duration.
What is Better?
Despite the advantages of electronics, professional athletes, racers, divers and pilots prefer good old-time and time-tested mechanics. It obeys only the laws of physics, so it turned to be more reliable in critical situations. For example there was a well-known occasion when the crew of Apollo-13 was left in the open space with all the electronics failed. And only thanks to the Omega Speedmaster chronograph, the astronauts have managed to calculate the time of safe landing on Earth with accuracy to a fraction of a second.
As for precision, luxury models of Swiss mechanical watches with chronometer status have enhanced accuracy with an error from +6 to -4 seconds per day.
Mechanical watches are preferred by collectors and fans of watchmaking. The thing is every mechanical calibre is a work of micromechanics. It is a quite complex device, consisting of several hundreds of parts, and enclosed into a small case.
But it does not mean that a quartz watch is a second-grade product. Many Swiss brands produce quartz models along with mechanical ones. Sometimes one and the same model can be presented in both versions. The choice is a matter of taste and lifestyle. And it is possible to distinguish a mechanical watch from a quartz one visually – by the second hand. In most mechanical watches the second hand moves smoothly around the dial. And in quartz watches it makes one move per second.