Photovoltaic (PV), concentrating photovoltaic (CPV) and concentrating solar power (CSP) systems operate more efficiently when their mirrors, collectors and PV modules accurately track the course of the sun during the day. The more precise and trouble-free these systems are, the more efficient and profitable the solar power plants operate. By offering its linear actuator and bearings for swivel drives as a complete system, Schaeffler has taken another step towards the full integration of precision solar tracking systems for azimuth and elevation axes.
Custom designed, the linear actuator responsible for stroke movements in the elevation axis can withstand the harsh operating conditions typically found in solar power plants. The linear actuator is designed for dynamic loads of up to 5kN and static loads of up to 15kN. The actuator can reach a stroke travel of up to 1000mm at a stroke speed of 5mm/s.
The complete mechatronics system comprises the rolling bearings for the individual bearing positions, screw drive spindle and spindle nut, extension tube, compact housing with cover, seal, drive technology (motor and gearbox unit), the sensors, and rod end for connecting the actuator. The innovative design and high flexibility of the unit allow the stroke length and mounting to be matched precisely to individual customer requirements.
Protected from dust, sand, wind and rain, the linear actuator can operate in high temperatures. Due to an encapsulated housing, a reduced number of fully sealed joints, as well as an integrated motor, gearbox unit and entire drive technology, the linear actuator is able to operate maintenance-free. The sealing components provide the actuator with an IP66 protection rating, which prevents the ingress of contaminants such as water and sand. With its low-maintenance requirements and bearing supports, the linear actuator provides an operating life of up to 25 years.
The high precision axes ensure that the solar power plants generate optimum power output on a continuous basis. Schaeffler’s linear actuator concept can also be adapted for use in other sectors or applications depending on the technical and geometrical requirements.
Bearings for precision swivel motion
Schaeffler’s AXS angular contact rolling bearings and FAG X-life tapered roller bearings support the swivel drives that adjust the azimuth axis. These bearings have a high load-carrying capacity and can be set clearance free. This is an important prerequisite for high rigidity and positioning accuracy and therefore the efficiency of the entire tracking system.
The AXS series of rolling bearings have cylindrical rollers and raceways that are arranged at an angle to the bearing axis. The roller and cage assemblies comprise cylindrical rollers that are snapped into high-rigidity plastic cages with very close spacing. This means that high load ratings are achieved. A special feature of the AXS series are the conical bearing rings. These are manufactured using forming methods, making them cost effective. In addition, turned bearing seats are sufficient for supporting the bearing rings. This reduces the cost of adjacent components.
For more information on Schaeffler’s range of linear actuators and linear guidance systems, please request a copy of the ALE brochure; email or visit the website at www.schaeffler.co.uk.