Does the operation of the BMS control board cooling fan increase the radiated interference value?

Cooling fans, especially brushless DC motors, generate broadband noise during operation, which can significantly increase radiated interference in the BMS (Body Management System) in the tens to hundreds of MHz frequency band. The noise primarily originates from arcing and current surges caused by motor commutation. Suppression measures include installing a π-type filter near the fan power inlet, coupled with ferrite beads and ceramic capacitors. Metal-cased fans are preferred, and their casings should be well grounded to the system chassis to form shielding. Ensure the fan motor casing is grounded through a low-impedance path. Effective power filtering and structural shielding can suppress additional radiated noise introduced by the fan, preventing its negative impact on the overall EMC performance of the system.