Solar Tracking Systems

Solar Tracking Systems & How They Work

A solar tracking system positions various payloads―such as solar PV panels, reflectors or lenses―toward the sun. Trackers are used to maximize the amount of incoming light by following the sun as it moves across the sky. Solar trackers are categorized by the number and orientation of their axes and whether they employ fixed, single or dual axis tracking systems.

Single-Axis Trackers

A single-axis tracker orients PV modules along one axis of rotation, moving horizontally from east to west as the sun moves. Moving these enormous PV modules requires that the gearbox offer both load-holding and rotational torque – something only a highly specialized slewing drive can offer. Trackers utilizing slewing drives that engage a greater number of teeth on the pitch line of the gear ring will offer the maximum amount of strength, durability and performance. This ensures the tracker has the longest possible field life with the least amount of downtime or maintenance cost.

Dual-Axis Trackers

Dual-axis trackers rotate side to side and up and down, enabling even more precise tracking of the sun's movement. Dual-axis systems are grouped based on the orientation of their primary axes with respect to the ground, such as Tip-Tilt trackers (TTDAT) or Azimuth-Altitude trackers (AADAT). These trackers enable a higher energy output than single-axis systems. Given that they employ two degrees of freedom, utilizing strong and powerful slewing drives is even more important for reliable and continuous functionality in the field.

Solar Panel Tracking System Outputs

Slewing Drive, Slew Drive

Solar tracking systems have been shown to boost electricity output 27-39 percent over fixed versions. This is a tremendous increase in output, especially when you consider how it is multiplied within large solar panel tracking system installations. Even a conservative 25 percent output increase translates into substantially higher income for these large solar projects. This is a prime example of how economies of scale can help stem costs while increasing the return on investment.

Slewing Drives: A Critical Component

Slewing drives use a horizontal screw to turn a perpendicular axis gear. This combination reduces the speed of the driven member and also multiplies its power, increasing it proportionally as the speed decreases. The speed ratio depends upon the number of threads on the screw to the number of teeth in the gear. Sophisticated slewing drives employ an hourglass drive, also called a worm drive or worm gearset, which simultaneously engages up to 11 teeth instead of just one. This increased tooth engagement results in far greater strength and efficiency. These hourglass drives are perfect for applications that require load holding, rotational torque and survival to high wind loads. Slewing drives can also be made with two axes of rotation in one housing unit..

It makes sense to invest in solar trackers that employ strong, reliable, field-tested slewing drives for movement. A drive that uses hourglass worm technology will offer the greatest level of strength and power thereby increasing field life and decreasing downtime. Quality drives will continue to help generate optimal power more reliably for the duration of the installation.

Learn more about slewing drives through our engineering drawings, standard sizes, and our custom designs just for your project.

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