Models SMT-3, ST-1, ST-3
The Eppley Laboratory manufactures two types of Solar Trackers to be used with the Normal Incidence Pyrheliometer and the Cavity Radiometer.
The Automatic Solar Tracker, Model SMT-3 is a 2 axis, azimuth/elevation device programmed to align direct beam instruments with the normal incidence of the sun from any position on the earths surface. Tracking is achieved using a computer program which calculates the solar position for the time and location and transmits pulses to the drives, which then operate the 2 stepping motors. The stepping motors move the elevation and azimuth axes to the correct position. After initial installation, the tracker will continue to track the sun and reset during darkness. Only periodic resetting of the system clock is required.
Models ST-1 and ST-3, "green tracker" are electrically
driven using a clock-based motor which makes one revolution every
24 hours. The ST-1 is designed for use with a single instrument
while the ST-3 accommodates up to three. The ST-3 also
incorporates worm and gear fine adjustments for declination and
equation of time.