Slewing Drives in the Solar Energy Industry

August 15, 2016- To build an effective solar field you need to provide reliable energy over 30 years while maintaining an extremely low cost of installation and low cost of ownership over this time.

To greatly increase return on investment, solar trackers are used to continually point photovoltaic devices directly at the sun throughout the day and to move them out of the way in case of a dangerous wind storm.  An effective solar tracker is made up of a photovoltaic device (PV panels, CPV concentrator, etc.), a steel lattice structure to hold the arrangement, and an electro-mechanical device to rotate the tracker as it follows the sun.

The best electro-mechanical device for operating a solar tracker is a slewing drive.  A slewing drive combines bearing, rotation, turning torque, and motion control into a single, simple to use device.  This is very critical from cost, ease of installation, and bill of materials control perspective.

Slewing drives can be set to any rotation angle without changing the size of the drive housing.  This allows the solar structure to be mounted lower to the ground, which allows the user a large cost savings in using a shorter steel support structure for miles of solar arrays.  At the end of the day, higher angle of rotation allows you a greater energy output because you can point directly at a setting sun.  Late in the day is a typical high load period for energy grids because air conditioners and general public usage is highest during that time.

Reliability is of utmost importance in the solar industry because electrical energy is being output to the grid and is expected to always be available.  If anything breaks down in the system, then no power is available.  This is detrimental to the owner and operator of the power plant.  Slewing drives have been shown through field usage, accelerated life cycle testing and third party reports to be the most reliable type of drive found for use in a solar field.

Minimizing operational and maintenance costs (O&M costs) is paramount because these costs add directly to the cost of power.  Third party reports have proven that fields using solar trackers with slewing drives have less than 2% more O&M costs than just a fixed panel field, while increasing power 20-40%

Solar fields must endure extreme conditions of sand, temperature, rain, salt and wind.  Kinematics manufactures a specialty designed hourglass worm slewing drive that allows for 5-11x greater wind survivability load than standard drives.  All the materials including the metals, rubbers, grease and finishes are manufactured to survive the extreme field conditions.