EMC electromagnetic compatibility testing

The electromagnetic interference sources of household appliances are mainly generated by sparks generated during the operation of the commutator motor inside the appliance, as well as the action of mechanical switches, various controllers, and protectors. For example, vacuum cleaners, hair dryers, mixers, razors, and other electric motors with commutators generate electromagnetic interference during operation when the electric brushes come into contact with the commutators to form sparks; Electric rice cookers, electric irons, electric ovens, washing machines, etc. generate electromagnetic interference due to frequent on-off movements; The high current required for starting the air conditioner will temporarily decrease the voltage of the power grid, and the starting of inductive loads such as motors will cause a decrease in the power factor of the power supply. The power electronic devices in the variable frequency air conditioner will also generate power harmonics, etc; The multifunctional controller of the electric fan is equipped with controllable silicon devices, which generate high-order harmonic disturbances; Home appliances with remote control, fully automatic washing machines, electric water heaters, microwave ovens and other household appliances with microprocessors use two-level digital signals that can cause electromagnetic interference, and as the clock frequency continues to increase, the interference frequency can reach several hundred megahertz; The leakage of electromagnetic energy generated by microwave ovens and induction cookers not only causes electromagnetic interference, but also poses a threat to human health.