A wind speed sensor is a device used for measuring the speed of the wind. They are useful for predicting the wind speed and also help in forecasting it. There are different types of wind speed sensor models. The working principle for important wind speed sensor models are discussed below:
Propellor Type Wind Speed Sensors
Propellor wind speed sensors have a set of 3-4 bladed propellors with its axis parallel to the wind direction. The blade system that is aligned to the airflow is subject to wind pressure. this creates a torsional moment that rotates the blades of this wind speed sensor. The propellor in these wind speed sensors is always mounted in front of a weathervane. This ensures that its plane of rotation is always facing the direction of the wind. The speed of turning of the blades is dependent on the wind speed. Propellor type wind speed sensors provide reliable results in conditions where the air motion remains constant, like in ventilating shafts of mines and buildings.
Wind Cup Type Wind Speed Sensors
These wind speed sensors are very common and were invented by British Rubinson. The sensing part of these wind speed sensors has 3-4 conical or hemispherical empty cups. The concave surfaces of the cups are classified in one direction. The entire cross arm frame is installed on a vertical rotating shaft. When the air flows past these cups, they rotate them at a speed that is proportional to the wind speed. You can count the number of turns of the cups in a fixed time interval to get the average wind speed. These wind speed sensors are also known as a rotational anemometer. The 3-cup model is most widely used in these wind speed sensors for measuring the wind speed for studies and practice.
Thermal Wind Speed Sensors
Thermal wind speed sensors use hotwire made of tungsten or platinum or a hot film made of platinum or chrome as a probe. The wire is exposed to the air and connected to the Wheatstone bridge. It measures the flow rate of the air. Thermal wind speed sensors that use hot film are coated with a thin quartz film which insulates it from fluid and protects from contamination. The airflow speed measurement by thermal wind speed sensors depends on the current and resistance. Hotwire thermal wind speed sensors have two design circuits of constant current and constant temperature with the latter being more common.