Working principle of wind cup type wind speed sensor
The wind cup wind speed sensor, a very common wind speed sensor, was first invented by Robinson in England. The sensing part is composed of three or four conical or hemispherical hollow cups. The hollow cups are fixed on a trident star-shaped bracket at 120° to each other or a cross-shaped bracket at 90° to each other, with the concave surfaces of the cups aligned in one direction, and the whole cross-arm frame is fixed on a vertical rotating axis.
When the wind is blowing from the left, the wind cup 1 is parallel to the wind direction, and the pressure of the wind on the wind cup 1 is approximately zero in the direction of the axis of the wind cup. Wind cup 2 and 3 with the wind direction into a 60-degree angle of intersection, for the wind cup 2, the concave side of the wind, the wind pressure to withstand the largest; wind cup 3 of its convex side to face the wind, the wind flow around the role of the wind pressure than the wind cup 2 is small, due to the wind cup 2 and the wind cup 3 in the perpendicular to the direction of the wind cup axis of the pressure difference, and so that the wind cup began to rotate in a clockwise direction, the greater the speed of the wind, the greater the pressure difference between the beginning of the greater the acceleration produced by the larger, the wind cup rotation The greater the wind speed, the greater the initial pressure difference, the greater the resulting acceleration, the faster the cup rotation.
After the wind cup begins to rotate, because the cup 2 rotates in the direction of the wind, the pressure of the wind is relatively reduced, and the cup 3 facing the wind to the same speed of rotation, the wind pressure is relatively increased, the wind pressure difference decreases, after a period of time (when the wind speed is unchanged), the action of the three cups of the pressure difference of zero, the wind cup will become a uniform speed rotation. According to the rotational speed of the wind cup (the number of revolutions per second) can determine the size of the wind speed.
When the wind cup rotates, drive the coaxial multi-tooth cut-off disc or magnetic bar rotation, through the circuit to get and the wind cup speed is proportional to the pulse signal, the pulse signal counted by the counter, after conversion can be derived from the actual wind speed value. At present the new rotating cup anemometer are used three cups, and conical cup performance than hemispherical good, when the wind speed increases the rotating cup can quickly increase the speed to adapt to the air speed, wind speed decreases, due to the impact of inertia, the speed can not be immediately decreased, rotating anemometer in the gust wind wind speed indicated by the wind speed is generally on the high side to become too high effect (resulting in an average error of about 10%)
