EMC (Electromagne TIc CompaTIbility) is electromagnetic compatibility. It is a technology for studying electromagnetic interference. Electromagnetic interference is the undue response of our peripheral electromagnetic energy to the operation of electronic equipment. The technical purpose of EMC is to make electrical equipment or systems immune to the electromagnetic environment and to the environment under common electromagnetic environment conditions. Below we understand the following three important rules of the EMC field and three elements of the EMC problem: Law 1. The relationship between EMC cost-effectiveness ratio: The earlier the EMC problem is considered, the earlier it is solved, the smaller the cost and the better the effect. In the new product development stage, the EMC design is carried out. When the EMC test is not qualified, the cost can be greatly improved, and the efficiency can be greatly improved. Conversely, the efficiency will be greatly reduced and the cost will be greatly increased. Experience tells us that EMC design is carried out at the same time as functional design, and EMC testing is completed when the prototype and prototype are completed, which is the most time-saving and most economical. On the contrary, EMC is not considered in the product development stage. After the production is completed, it is found that the EMC is not qualified to be improved. This is not only technically difficult, but also rework, which inevitably leads to a waste of cost and time, even due to structural design and PCB design. Defects, unable to implement improvement measures, resulting in products not available. Rule 2: The larger the area S of the high-frequency current loop, the more severe the EMI radiation. The high frequency signal current flows through the minimum path of the inductor. When the frequency is high, the general line reactance is greater than the resistance, and the connection to the high frequency signal is the inductance, and the series inductance causes the radiation. Most of the electromagnetic radiation is generated by the high-frequency current loop on the EUT device under test. The worst case is the open-circuit antenna form. The corresponding processing method is to reduce and shorten the connection, reduce the area of ​​the high-frequency current loop, and try to eliminate any antennas that are needed for abnormal operation, such as discontinuous wiring or long pins with components with antenna effects. One of the most important tasks to reduce radiated harassment or improve the anti-interference ability of RF radiation is to find ways to reduce the high-frequency current loop area S. Rule 3: The higher the loop current frequency f, the more severe the EMI radiation caused, and the electromagnetic radiation field strength increases in proportion to the square of the current frequency f. The second most important way to reduce radiation disturbance or improve the anti-interference ability of RF radiation is to find ways to reduce the frequency f of the high-frequency current of the disturbance source, that is, reduce the frequency f of the disturbance electromagnetic wave. Switching power supplies and digital devices generate strong radiation due to the high frequency harmonics of the pulse current and voltage. Electromagnetic interference includes radiated (high-frequency) EMI, conductive (low-frequency) EMI, that is, EMC problems occur mainly through two ways: one is the form of space electromagnetic wave interference; the other is through the form of conduction, in other words, generating EMC The three elements of the problem are: electromagnetic interference sources, coupling paths, and sensitive equipment. Radiation interference mainly pollutes the space electromagnetic environment in the form of electromagnetic waves through the casing and the connecting line; the conducted interference is the device that affects the connection through the power line to disturb the public power grid or through other terminals (such as: RF terminal, input terminal). Conduction, radiation Source of Harassment -------------------- (Pathway) -------------------- Sensitive Receptor Near field coupling Possible sources of harassment for IT and AV equipment A) The FM receiver and the TV receiver oscillate locally, and the fundamental wave and harmonics are generated by the high frequency head and the local oscillator circuit; B) switching pulse and higher harmonics of the switching power supply, synchronous signal square wave and high frequency harmonics, line and field signals generated by the line scanning developing circuit and high frequency harmonics; C) Various clock signals and high-frequency harmonics required for digital circuit operation, and their combinations, such as CPU chip operating clock, MPEG decoder operating clock, video synchronous clock (27MHz, 16.9344MHz, 40.5MHz), etc. ; D) unwanted signals and spurious signals caused by digital signal square wave and high frequency harmonics, higher harmonics generated by crystal oscillator, nonlinear circuit phenomena (nonlinear distortion, intermodulation, saturation distortion, cutoff distortion); E) Non-sinusoidal waveforms, waveforms, overshoots, ringing, parasitic frequency points in the circuit design. F) External disturbances received by sensitive receptors via coupling pathways include surges, fast bursts, static electricity, voltage dips, voltage changes, and various electromagnetic fields. Characteristics of electromagnetic disturbance 1 The spectrum of the unit pulse is the widest; 2 The low frequency content in the spectrum depends on the area of ​​the pulse, and the high frequency component depends on the steepness of the front and back edges of the pulse; 3 The crystal oscillation level must meet a certain amplitude, and the digital circuit can work according to a certain timing, so that the disturbance generated by the crystal oscillator exhibits the characteristics of covering bandwidth and high disturbance level; 4 When the polarization of the transmitting and receiving antennas is the same, the EMI radiation and reception are the most serious; the larger the area of ​​the transmitting and receiving antennas, the greater the EMI hazard; 5 Harassment pathway: combination of radiation, conduction, coupling and radiation, conduction, and coupling. 6 Power line conducted disturbances are mainly generated by common mode currents; 7 Radiated disturbances are mainly generated by loops formed by differential mode currents. III. Concluding remarks: Understanding the three rules of EMC and the three elements of EMC problem will make the EMC problem changeable. The law of EMC will make solving the EMC problem save time and effort, and get twice the result with half the effort.
Diesel generator assembly by diesel engine, alternator, radiator, controller, base frame;
. World famous diesel engine brand: Cummins, Perkins, MTU, Kubota, Yuchai, Mitsubishi, Deutz, Doosan, MWM, GE, CRRC, Etc
. World famous AC alternator brand: Stamford, Leroy Somer, Mecc Alte, Marathon, Faraday, SWT
. World famous genset controller brand: Deepsea, ComAp, Deif, SmartGen,
. Good Quality Cooling Radiator
. Start Battery System
. Fuel Supplying System
. Filtering System
. Intake and Exhaust System
Diesel Genset,Diesel Generator,Diesel Generator Set,Portable Diesel Generator Guangdong Superwatt Power Equipment Co., Ltd , https://www.swtgenset.com