Wind speed sensor is a common sensor that can continuously measure wind speed and air volume (air volume = wind speed x cross-sectional area). Wind speed sensors are generally divided into mechanical (mainly propeller type, wind cup type) wind speed sensor, hot air wind speed sensor, pitot tube wind speed sensor and ultrasonic wind speed sensor based on acoustic principle. About the wind cup type wind speed sensor working principle, let’s understand.
Wind cup type wind speed sensor, also known as three cup type wind speed sensor, is a very common weather sensor, first invented by British Robinson. The induction part consists of three or four empty cups, conical or hemispherical. The hollow cup shell is fixed on a three-fork star bracket that is 120° to each other or a cross bracket that is 90° to each other. The concave sides of the cup are arranged in one direction, and the whole transverse arm is fixed on a vertical axis of rotation.
When the wind blows from the left, cup 1 is parallel to the wind direction, and the portion of the wind pressure on cup 1 in the direction most direct to the cup axis is approximately zero. Wind cup 2 and 3 intersect at an Angle of 60 degrees with the wind direction. For wind cup 2, its concave surface faces the wind and bears the maximum wind pressure. The convex surface of wind cup 3 faces the wind, and the wind flow around it makes the wind pressure less than that of wind cup 2. As the pressure difference between wind cup 2 and wind cup 3 is perpendicular to the axis of wind cup, the wind cup starts to rotate clockwise. The higher the wind speed, the greater the initial pressure difference, the greater the acceleration, and the faster the rotation of wind cup.
Wind cup started turning, because the cup 2 along the direction of the wind, the wind pressure relatively decreased, and the cup three against the wind turn, at the same speed by wind pressure increases relatively, falling of leeway, after a period of time (at constant speed), the role in the partial pressure difference of the three wind cup is zero, the wind cup it became a uniform rotation. In this way, the speed of the wind can be determined according to the speed of the wind cup (the number of revolutions per second).
When the wind cup rotates, it drives the coaxial multi-tooth cutting disc or magnetic rod to rotate. Through the circuit, the pulse signal is proportional to the speed of the wind cup. The pulse signal is counted by the counter, and the actual wind speed can be obtained after conversion. The new cup anemometer is used three cups, and the performance of the conical cup is better than hemispherical, when wind speed increases quickly increased rotor speed, to adapt to the air velocity, wind speed reduced, due to the inertia influence, speed is not immediately fell, the rotary anemometer instructions in the gustiness wind wind speed is generally on the high side as high effect (the average error is about 10% )