 Calibration
Devices: Wind
A. Wind Direction Calibrator
The Model 1249-A Wind Direction Calibrator is a mechanical device used to
calibrate systems which include Micro Response or Low Threshold wind vanes
(Model 2020 or 2005). It mounts directly on the vane and has three possible
uses. First, it can be used to position the vane at four points, exactly 90°
apart, to check the readings of output devices. Second, it can be used in
sigma system calibration to give a direction change of exactly 90°. And
third, it can be used to hold the vane tail in place during orientation to
north. A similar device, the Model 1247, is available to assist in wind direction
calibration of the Skyvane sensor.
 B.
Wind Speed Calibration
The purpose of the wind speed calibrator is to simulate a known wind speed
condition in order to calibrate or evaluate the anemometer for its proper
output. The calibrator attaches to the shaft of the anemometer through the
use of neoprene tubing. The calibrator rotates the shaft at a constant RPM
which corresponds to a known wind speed value that has been determined through
wind tunnel testing. The calibrators employ constant speed synchronous motors
whose rotation rate changes as a function of the AC line frequency.
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