No sé si en todos los casos será igual.
He encontrado esta explicación para el movimiento 9300 de Omega.
"Besides a beating heart, a watch movement also needs a place to accumulate the energy. This is where the barrel & mainspring come in. While many manufactures opt to go for multiple barrels as to enlarge the power reserve, this is not the case with Omega – although the caliber 9300 has an over-average power reserve of 60h.
So what is the point if not the lengthen the power reserve? To increase the stability of the rate over an extended period of time. In an automatic movement, the barrel is traditionally fitted with a slip clutch as to prevent over winding. In Omega’s Two Barrel system, the first barrel is constructed in the style of a manual wind movement – sans slip clutch. The second can be considered a traditional barrel for automatic movement – with slip clutch. When the first one is ‘filled’ to the max, the second one takes over.
When winding down -in other words, when the watch is running-, it first uses the energy stored in the second barrel. When that energy is equal to that of the first barrel, both will start releasing their energy simultaneously. As such, the released energy will be at a constant level for an extended period of time, thus minimizing the loss of accuracy due to decreased torque."
Parece que el primer barrilete es como el de un reloj de cuerda y el segundo como el de un automático, con embrague para evitar sobrecarga.
El segundo parece que es el que suministra el par.
Como la pregunta es interesante, y yo muy poco experto en relojes, aprovecho para subir el hilo y ver si alguien más avezado nos ilustra
Enviado desde mi iPad utilizando Tapatalk
