With the further improvement of the modernization of medical instruments and equipment, various types of operating electrical equipment are associated and interact with each other in three ways: electromagnetic conduction, electromagnetic induction, and electromagnetic radiation.
They will cause disturbance, effects, and hazards,for operating equipment and personnel under certain conditions.
1# The way of interference
The interference is divided into differential mode interference, common mode interference, and series mode interference.
Differential mode interference is also called normal mode interference, transverse mode interference or symmetrical interference. It refers to the interference that is superposed on the sine wave of the line voltage and is the interference between the current carrying conductors. Such as grid over-voltage, transient mutations, spikes and so on.
Common mode interference is also called longitudinal mode interference, asymmetric interference and grounding interference. It refers to the interference generated between the grid and the neutral line. It is the interference between the current carrying conductor and the earth. It is coupled to the circuit by radiation or interference come. Such as peak interference, radio frequency interference, the steady-state voltage between the zero line and ground. Series-mode interference refers to interference caused by external magnetic field electric fields.
All electronic devices now produced contain electromagnetic interference filter circuits. Similarly, all switching power supplies have internal EMI filters. However, in some environments, the EMI filters for these electronic devices require auxiliary filters to meet more stringent electrical noise regulations or protect the device from excessive external noise sources.
2# Types Of Interference
All electronic devices now produced contain electromagnetic interference filter circuits. Similarly, all switching power supplies have internal EMI filters. However, in some environments, the EMI filters for these electronic devices require auxiliary filters to meet more stringent electrical noise regulations or protect the device from excessive external noise sources.
The types of power disturbances include voltage drop, loss of power, frequency offset, electrical noise, surges, harmonic distortion, and transients.