Depending on the requirements and application, either an AC, EC, or DC motor is used – mainly as an external rotor motor. This is because the impeller can be mounted directly onto the rotor. This makes the impeller motor unit extremely short and compact, creating more space for air flow.
Of course, the impeller is an elementary component. The impeller is crucial for air acceleration and generating work in the form of pressure. Across all of the designs, the air is drawn in parallel to the axis of rotation and flows out again according to the blade characteristics. For axial fans, for example, the air flows out mainly parallel to the axis. For safety reasons, the impeller blades are often fitted with guard grills so that no one can hurt themselves on them. To achieve good efficiency, an axial fan’s impeller should be positioned in a fan housing that has been aerodynamically optimized. Together with a front plate, this ensures air flow control and provides the separation required between the intake and outlet sides.
Due to the different types of flow through the impeller, the fan designs have different operating characteristics. If operated using an EC motor, commutation electronics are required. The sensors integrated in the motor allow the electronics to precisely detect the position of the rotor in relation to the coils. To that effect, the coils are energized and the rotor is turned. In addition, the built-in electronics process control signals and store status information.
Regardless of the fan type and purpose, additional noise insulation is useful for operation in noise-sensitive areas. For this purpose, a FlowGrid is mounted on the intake side of the fans – for a lower noise level and a drastically dampened blade passing noise. As a result, the air performance remains unchanged.
If all of the parts are optimally matched, the fan is able to meet the requirements with respect to operating conditions, performance, and environmental influences.
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