Radio frequency interference of electric motors and associated controls

Problems of radio-frequency interference (RFI) caused by electric motors used in appliances are discussed in general terms, and some possible solutions are given. Elimination of such noise or suppression to permissible levels is difficult and expensive. Various aspects of motor design, like electric/magnetic loading ratio, commutation and sparkling, and brushes and brush gears, which all affect RFI, are discussed. Suppression components and their use in high-frequency (HF) and very-high-frequency (VHF) ranges, including their dispositions, are discussed. Aspects and techniques of measurement of noise level are presented