Analysis and Application of EMC EFT Immunity Tester: A Case Study of LISUN EFT61000 – 4

Abstract:

This paper focuses on the EMC EFT immunity tester, especially the LISUN EFT61000 – 4 EFT Immunity Measurement product. It elaborates on the principles of electrical fast transient (EFT) and burst phenomena, the significance of EFT immunity testing, and the relevant international standards. The structure, features, and operation procedures of the LISUN EFT61000 – 4 are introduced in detail. Through theoretical analysis and practical application examples, this paper aims to provide a comprehensive understanding of EFT immunity testers and their crucial role in ensuring the electromagnetic compatibility of electrical and electronic equipment.​

1. Introduction​
In the modern era of increasing electrification and digitalization, electrical and electronic equipment is everywhere. However, with the growing complexity of the electromagnetic environment, the interference between different devices has become a prominent issue. One of the typical and common types of electromagnetic interference is the electrical fast transient (EFT) and burst. To ensure the reliable operation of equipment in such an environment, EFT immunity testing is of great significance, and the EMC EFT immunity tester is the key instrument for this type of testing. The LISUN EFT61000 – 4 EFT Immunity Measurement product, as a representative in this field, has attracted extensive attention due to its excellent performance and compliance with international standards.​

2. The Phenomenon and Mechanism of Electrical Fast Transient (EFT)​

2.1 Generation of EFT​

EFTs are typically high – frequency pulses produced by sparking and are frequently observed in electrical systems and equipment. These sparks, also known as arcing, happen when lines touch, when a circuit is connected to or disconnected from a power source, or when switchgear is in use. When inductive loads like relays or motors are de – energized, EFTs, also known as burst events, occur in power distribution lines; power factor correction equipment is also a source of EFTs. In addition, Ethernet networks, data cables, and electric car systems are other technologies that have EFT problems.​

2.2 Characteristics of EFT​

EFTs are characterized by fast – rising edges, short durations, low energy, but high repetition frequencies. For example, a standard EFT pulse has a rise time of about 5 ns, a pulse width of about 50 ns, and can have a repetition frequency of 5 kHz or 100 kHz. The EFT is composed of continuous pulse trains with an interval of 300 ms, and each pulse train lasts for 15 ms. Although the energy of a single pulse is relatively small and generally does not cause equipment damage, due to its wide – spectrum interference distribution, it can seriously affect the normal operation of equipment.​

2.3 Interference Mechanism of EFT​

The interference mechanism of EFT is mainly that it continuously charges the semiconductor junction capacitance in the circuit unidirectionally. As the energy accumulates, it may eventually cause the circuit or equipment to malfunction. For digital systems, this may lead to bit errors, system resets, memory errors, and even system crashes. In analog circuits, it can cause signal distortion and inaccurate measurements.​

EFT61000-4_EFT Immunity Measurement

3. Significance of EFT Immunity Testing​

3.1 Ensuring Equipment Reliability​

In real – world applications, electrical and electronic equipment is often exposed to various electromagnetic interferences, including EFTs. If the equipment cannot effectively resist EFT interference, it may malfunction during operation, leading to serious consequences such as system failures in industrial control systems, incorrect diagnoses in medical devices, and data loss in information technology equipment. EFT immunity testing helps to ensure that the equipment can operate stably and reliably in a complex electromagnetic environment.​

3.2 Meeting Industry Standards​

In the international market, there are strict electromagnetic compatibility (EMC) standards for electrical and electronic products. For example, the IEC 61000 series of standards, especially IEC 61000 – 4 – 4, clearly defines the requirements and test methods for EFT immunity testing. Complying with these standards is not only a necessary condition for product market access but also an important means to ensure product quality and safety. By conducting EFT immunity testing, manufacturers can ensure that their products meet international and domestic industry standards and enhance their competitiveness in the global market.​

3.3 Reducing Maintenance and Replacement Costs​

Equipment that fails to pass EFT immunity testing is more likely to experience malfunctions during use. This will not only cause direct losses due to equipment downtime but also incur high maintenance and replacement costs. Through EFT immunity testing in the product development and production stages, potential problems can be detected and resolved in a timely manner, reducing the probability of equipment failure in the later stage and effectively reducing maintenance and replacement costs.​

4. International Standards Related to EFT Immunity Testing​

4.1 IEC 61000 – 4 – 4 Standard​

The IEC 61000 – 4 – 4 standard is the most fundamental and important standard in EFT immunity testing. It provides a unified and repeatable standard for testing the performance of the power supply ports, I/O and communication ports, and cabinet earth ports of electrical and electronic equipment under EFT/burst conditions. This standard clearly stipulates the test voltage waveform, test levels, test equipment, and required test conditions.​
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The test results are classified according to the loss of function or degradation of performance of the equipment under test:​
• Class A: Normal performance within the limits specified by the manufacturer, requestor, or purchaser.​
• Class B: Temporary loss of function or degradation of performance that ceases after the disturbance ceases, and from which the equipment under test recovers its normal performance without operator intervention.​
• Class C: Temporary loss of function or degradation of performance, the correction of which requires operator intervention.​
• Class D: Loss of function or degradation of performance that is not recoverable, owing to damage to hardware or software, or loss of data.​

4.2 Other Related Standards​

In addition to IEC 61000 – 4 – 4, there are other relevant standards such as EN 61000 – 4 – 4 in the European Union, which is basically consistent with the IEC standard but may have some regional – specific requirements. In China, standards such as GB/T 17215.301, GB/T 17215.322, and GB/T 17626.4 also refer to the IEC 61000 – 4 – 4 standard, ensuring that domestic electrical and electronic products meet international – level EMC requirements.​

5. Introduction to LISUN EFT61000 – 4 EFT Immunity Measurement Product​

5.1 Product Structure and Components​

The LISUN EFT61000 – 4 EFT Immunity Measurement product is a high – performance EFT immunity tester. It mainly consists of a main control unit, a high – voltage power supply module, a pulse generation module, a coupling/decoupling network, and a human – machine interface. The main control unit is responsible for overall control and parameter setting of the tester. The high – voltage power supply module generates high – voltage DC power required for pulse generation. The pulse generation module, under the control of the main control unit, generates EFT pulses with specific waveforms and parameters. The coupling/decoupling network is used to couple the generated EFT pulses to the equipment under test (EUT) and decouple the interference from the power grid, ensuring the accuracy and effectiveness of the test. The human – machine interface, which is an LCD touch screen with both English and Chinese, provides users with a convenient and intuitive operation method.​

5.2 Product Features​

High Stability and Reliability: The LISUN EFT61000 – 4 adopts advanced circuit design and high – quality components, ensuring stable output of EFT pulses during long – term operation and high – reliability test results.​
• Compliance with Multiple Standards: It complies with international and domestic standards such as IEC 61000 – 4 – 4, EN 61000 – 4 – 4, GB/T 17215.301, GB/T 17215.322, and GB/T 17626.4, which makes it suitable for use in different regions and industries.​
• User – Friendly Operation: The LCD touch – screen interface with bilingual display simplifies the operation process. Users can easily set test parameters such as pulse voltage, repetition frequency, and test time through the touch – screen, and the instrument can also display real – time test status and results.​
• Powerful Function: The maximum output current of the LISUN EFT61000 – 4 can reach 5 kV, which can meet 4 standard test levels and reserve a custom special test level. In addition, the instrument has a built – in three – phase 20A coupling and decoupling network (CDN), which can adapt to different types of EUTs, including single – phase and three – phase equipment.​

5.3 Operation Procedure​

• Test Preparation: First, connect the LISUN EFT61000 – 4 to a stable power supply and turn it on. Then, connect the equipment under test (EUT) to the coupling/decoupling network of the tester according to the test requirements. Ensure that the connection is correct and firm.​
• Parameter Setting: Through the LCD touch – screen, set the relevant test parameters, including the test level (voltage peak), pulse repetition frequency, pulse width, test time, and the number of positive and negative pulse trains. For example, if testing a product according to Level 3 of the IEC 61000 – 4 – 4 standard, set the voltage peak to 2 kV.​
• Waveform Verification: Before starting the formal test, it is necessary to verify the EFT waveform output by the tester. The tester can display the generated EFT waveform on the screen. Compare the waveform with the standard waveform specified in IEC 61000 – 4 – 4 to ensure that the waveform meets the requirements in terms of rise time, pulse width, etc.​
• Test Execution: After confirming that the parameters and waveforms are correct, start the test. The LISUN EFT61000 – 4 will generate EFT pulses according to the set parameters and couple them to the EUT through the coupling/decoupling network. During the test, observe the operating status of the EUT and record any abnormal phenomena.​
• Result Evaluation: After the test is completed, evaluate the test results according to the classification criteria of the IEC 61000 – 4 – 4 standard. If the EUT can operate normally within the specified limits, it belongs to Class A; if there is temporary loss of function or performance degradation that recovers automatically after the disturbance stops, it belongs to Class B, and so on.​
• Test Report Generation: Finally, generate a detailed test report based on the test results. The test report should include information such as the test date, test equipment model, EUT model, test parameters, test results, and waveform diagrams.​

6. Application Examples of LISUN EFT61000 – 4​

6.1 Application in Industrial Control Systems​

In industrial control systems, a large number of electrical and electronic devices are used, and they are often exposed to a complex electromagnetic environment. For example, in a factory’s automated production line, programmable logic controllers (PLCs), frequency converters, and various sensors are interconnected. Using the LISUN EFT61000 – 4 to test these devices can ensure their normal operation in the face of EFT interference. In a test of a PLC, when subjected to EFT pulses with a voltage peak of 2 kV (Level 3) generated by the LISUN EFT61000 – 4, the PLC did not experience any abnormal phenomena such as misoperation or data loss, indicating that the PLC has good EFT immunity.​

6.2 Application in Medical Devices​

Medical devices are crucial for human health, and their reliability and safety are of utmost importance. EFT interference may affect the accuracy of medical device measurements or even lead to incorrect diagnoses. For example, when testing an electrocardiogram (ECG) machine with the LISUN EFT61000 – 4, if the ECG machine can still accurately record the electrocardiogram waveform without distortion or error under EFT interference, it means that the ECG machine meets the EFT immunity requirements. This helps to ensure the safety and effectiveness of medical devices in the medical environment.​

6.3 Application in Information Technology Equipment​

In the field of information technology, equipment such as computers, servers, and network devices is also vulnerable to EFT interference. For example, a network switch was tested using the LISUN EFT61000 – 4. During the test, the switch was required to maintain normal data transmission and network connection functions under EFT pulses. The test results showed that when the interference level reached Level 2 (1 kV), the switch still operated normally, but when the level was increased to Level 3 (2 kV), the switch experienced occasional packet loss, indicating that the switch needs further improvement in EFT immunity.​

7. Conclusion​

The EMC EFT immunity tester, especially products like the LISUN EFT61000 – 4, plays a vital role in ensuring the electromagnetic compatibility of electrical and electronic equipment. Through a comprehensive understanding of the EFT phenomenon, the significance of EFT immunity testing, and relevant international standards, as well as a detailed introduction to the LISUN EFT61000 – 4 product and its application examples, it can be seen that EFT immunity testing is an essential link in the development, production, and quality control of electrical and electronic products. With the continuous development of technology and the increasing complexity of the electromagnetic environment, the importance of EFT immunity testers will become more prominent. Manufacturers and researchers should pay more attention to EFT immunity testing and continuously improve the performance of equipment to meet the challenges of the modern electromagnetic environment.​

In the future, it is expected that EFT immunity testers will continue to develop in the direction of higher precision, more intelligent operation, and wider application scenarios, providing more reliable technical support for the electromagnetic compatibility of various electrical and electronic products.