What is Asservicement?

Asservicement is the intelligent motor control system of a quartz watch. The purpose of asservicement is to ensure that the bi-polar motor, the Lavet motor, rotates while using the least amount of energy possible.

Describe the two functions of asservicement.

Asservicement has two functions. These functions are the Chopped Motor Drive and Step Detection.

How does asservicement make the quartz watch more efficient?

Asservicement makes the quartz watch more efficient by using the two parts, chopped motor drive and step detection, in unison. I will explain each part to answer this question.

1: The Chopped Motor Drive - The theory behind this drive is that the motor can be turned on and off quickly to maximize the amount of power consumed by the watch. Basically, the more the watch is powered, the more torque it has. The chopped motor drive limits this power by detecting the movement of the Lavet motor. If the motor is using a function such as the date change then more power is required to turn the drive wheels. If this function is not being used the only the amount of power needed to run the going train is supplied. Not only is it less power, but it is also is smaller increments. Visualize the power being on 15% of the time instead of 100% of the time, that would save 85% of the energy reserve. This in turn makes the entire watch more efficient. Each cycle of power is called a duty cycle and the measurement of each cycle is a pulse width. This is measured in milliseconds.

2: Step Detection - Step detection is the part of asservicement that ensures the bi-polar (Lavet) motor has advanced one step ( 180 degrees of rotation). If a step is not detected, more power is supplied until a step is detected. This happens until the maximum voltage is reached in the watch. The step detection helps make the watch more efficient by only supplying the minimum current needed. Both the Chopped Motor Drive and Step Detection together are asservicement and asservicement makes the quartz watch more efficient.

Link for a powerpoint about how a quartz watch works with asservicement