INTRODUCTION
A solar tracker is a mechanical device which is able to favorably move to the solar rays a photovoltaic panel, a solar thermal panel or a solar concentrator. The main purpose of a tracker is to maximize the efficiency of the device hosted on board. In a photovoltaic field the modules installed on a tracker are usually arranged geometrically on a single panel in order to avoid the use of a tracker for each module. According to their design features solar trackers are classified according to: their degrees of freedom, the type of power supply provided by orientation mechanism and the type of electronic control. Solar trackers are able to offer to the panel a single or dual axis freedom of movement. Among one degree of freedom trackers, can be mentioned: - Tilt (i.e. pitching) trackers which are the easiest to implement; they rotate around east-west axis (X axis). The panel is raised or lowered (usually manually twice a year) toward the horizon so that the angle to the ground is statistically optimal according to the seasonality. In practice, a tilt tracker is made using telescopic mechanical profiles in order to raise or to lower the solar panel respect to the horizon. Conceptually similar to the lifting shelf of a school desk these trackers offer a production increase of less than 10% that doesn’t justify a servomechanism.
