Dynamic Analysis of Natural Frequencies in Air Blower Motors Considering Blade Count and Gyroscopic Effects

Air blower motors, integral to various industrial and HVAC applications, consist of a shaft connected to a fan assembly. Improper consideration of natural frequencies in their design can lead to significant vibrational issues and operational failures. This study systematically investigates the influence of blade count on the natural frequencies of an air blower motor in both stationary and dynamic rotational states, including the gyroscopic effects observed during forward and backward whirling modes. A finite element model was developed and validated for mesh independence, confirming that the natural frequencies are largely unaffected by mesh refinement. Simulation results reveal that increasing the number of blades reduces the natural frequency, primarily due to the added mass, with more pronounced effects observed at higher operational speeds. The findings contribute valuable insights into the design optimization of blower systems, highlighting strategies to avoid critical speed resonance and enhance mechanical reliability.