Radial-flow fans that are suited for rotation in both directions are employed for the standard type. The fans used have broad and shallow blades. Thus, they are capable of conveying large volume of air efficiently and at low noise level.

For more stringent requirements, we recommend the low-noise variant with uni-directional axial-flow fan. With the aerodynamic design of fan blades and the optimization of the pitch angle, a noise reduction of up to 10 dB(A) can be achieved compared to the standard version. At the same time, the efficiency of the motors is increased due to the reduction in power consumption of the fan.

For applications requiring extremely low noise level, ATB has developed a range of exceptionally quiet, surface-cooled three-phase motors. These motors are approx. 12 dB(A) quieter than the standard version, radial-flow fan counterparts, and are even quieter than the low-noise axial-flow fan motors.
These motors achieve the reduced noise values without the use of secondary sound damping measures, such as e.g. sound insulation fan cowl. Through this, considerable cost savings can be achieved in the construction of low-noise equipments.