Electro Magnetic Interference
There are two kinds of Electro Magnetic Interference (EMI), referred by unwanted interference energies conducted as currents or radiated as electromagnetic fields. Agencies, such as Federal Communications Commission (FCC) and Verband Deutscher Elektrotechniker (VDE), have established rules governing EMI emissions. It is important for engineers to filter noise or eliminate ground loops. If resolved at the early fan design level, a simple by-pass capacitor or ferrite bead can improve the EMI problem.