EMC EMC test

The main source of electromagnetic interference of household appliances is the spark generated by the motor with commutator in the appliance and the action of mechanical switch, various controllers and protectors. For example, during the operation of motors with commutators, such as vacuum cleaners, hair dryers, agitators, and razors, the electric brush contacts with the commutators to form sparks and generate electromagnetic interference; Electric cooker, electric iron, electric oven and washing machine produce electromagnetic interference due to frequent switching action; When the air conditioner starts, the large current will make the grid voltage drop temporarily. When the motor and other inductive loads start, the power factor of the power supply will drop. The power electronic devices in the variable frequency air conditioner will also produce power harmonics; The multi-function controller of electric fan is equipped with silicon controlled device, which can produce high-order harmonic disturbance; The two-level digital signal used in household appliances with microprocessor, such as household appliances with remote control, automatic washing machines, electric water heaters, microwave ovens and so on, will cause electromagnetic disturbance, and with the continuous improvement of clock frequency, the disturbance frequency can reach hundreds of megahertz; The leakage of electromagnetic energy produced by microwave oven and induction cooker will not only cause electromagnetic disturbance, but also harm human health.

Cispr14-1 and cispr14-2 are the most important EMC standards for household appliances, while microwave oven and induction cooker (household electromagnetic induction apparatus) belong to two groups of class B equipment of industrial, scientific and medical (ISM) equipment, so their electromagnetic interference characteristics should meet the requirements of cispr11. The corresponding EMC standards of household appliances in EU are en 55014-1 and en 55014-2, while microwave oven and induction cooker are en 55011.

In the U.S. market, ordinary household appliances belong to the unintended RF equipment specified in FCC Part 15. They need to be "verified" to consumer ism equipment, and they need to meet the requirements of FCC Part 18. The certification mode needs to select doc (Declaration of conformity) or certification.