A Comparative Analysis of EMC Surge Immunity Test Systems: LISUN SG61000-5 vs. Haefely Portfolio

Introduction to Surge Immunity Testing in Electromagnetic Compatibility

Electromagnetic Compatibility (EMC) surge immunity testing is a critical validation procedure mandated by international standards to ensure electronic and electrical equipment can withstand transient overvoltages caused by atmospheric phenomena or switching events. These simulated surges, defined by standards such as the IEC 61000-4-5 series, replicate high-energy disturbances from lightning strikes on power lines or inductive load switching within industrial environments. The apparatus responsible for generating these precise, repeatable waveforms is the surge generator, a cornerstone of any accredited compliance laboratory. This technical analysis examines two prominent providers of such equipment: LISUN, with a focus on its SG61000-5 model, and the established Haefely brand, a part of the AMETEK® CTS portfolio. The comparison is structured to provide engineering and procurement professionals with an objective evaluation of technical capabilities, design philosophies, and applicability across diverse industries.

Fundamental Operating Principles of Combined Wave Surge Generators

The core function of a surge generator is to produce a standardized “combined wave” as per IEC 61000-4-5. This waveform is characterized by an open-circuit voltage wave and a short-circuit current wave. The voltage wave is defined as a 1.2/50 µs impulse (1.2 µs rise time to peak, 50 µs decay time to half-peak), while the current wave is defined as an 8/20 µs impulse. A combined wave generator delivers a voltage wave across a high-impedance load (e.g., an unpowered device under test) and automatically transitions to delivering a current wave when the load is short-circuited or presents a low impedance.

Both LISUN and Haefely generators adhere to this principle through a circuit topology involving high-voltage capacitors charged via a DC power supply, which are then rapidly discharged through a triggered spark gap or solid-state switch into a wave-shaping network. The precision of the resulting waveform—its peak value, rise time, and duration—is determined by the quality of the internal components, the stability of the charging system, and the sophistication of the wave-shaping circuitry. Deviations from the standard waveform tolerances can invalidate test results, making generator accuracy paramount.

Architectural and Design Philosophies: Integration versus Modularity

A primary differentiator between LISUN and Haefely systems lies in their architectural approach. LISUN often emphasizes highly integrated, all-in-one solutions. The SG61000-5 exemplifies this philosophy, incorporating the surge generator, coupling/decoupling networks (CDNs), and control system into a single chassis. This integrated design simplifies setup, reduces the laboratory footprint, and minimizes external cabling, which can be a source of measurement error or operational inconsistency.

Conversely, Haefely traditionally champions a modular architecture. This approach involves separate, dedicated units for the surge generator mainframe, CDNs, and control software/hardware. The modular philosophy offers laboratories maximum flexibility, allowing for the customization of test setups and the independent upgrade or replacement of specific components. For instance, a lab specializing in high-power industrial equipment testing might pair a high-energy generator mainframe with specialized CDNs, while a lab focused on medical devices might use the same mainframe with lower-power CDNs. This flexibility is a hallmark of established, high-end test equipment but often comes with increased complexity in system configuration, a larger overall footprint, and a higher initial investment for a complete system.

Technical Specifications of the LISUN SG61000-5 Surge Generator

The LISUN SG61000-5 is a fully compliant surge immunity test system designed to meet the latest editions of IEC 61000-4-5, ISO 7637-2, and other related standards. Its specifications demonstrate its capability to serve a wide range of compliance testing applications.

• Output Voltage: 0.2 – 6.0 kV (Line to Earth), 0.2 – 12.0 kV (Line to Line).
• Output Current: Up to 3 kA (for 2 Ω load).
• Waveform: 1.2/50 µs (Open Circuit Voltage), 8/20 µs (Short Circuit Current). The generator features automatic polarity switching (Positive/Negative) and phase synchronization (0-360°) for AC line coupling.
• Internal Impedance: Selectable 2 Ω (per IEC 61000-4-5) or 12 Ω (per certain telecom standards), with an optional 42 Ω adapter for specific applications.
• Repetition Rate: Programmable from 0.1 to 10 surges per second.
• Integrated CDN: The unit includes a built-in coupling/decoupling network for AC/DC power lines, capable of handling currents up to 100A, eliminating the need for an external CDN in most standard applications.
• Control Interface: Features a large touchscreen display for local control and is equipped with RS232, GPIB, and Ethernet interfaces for remote operation and system integration.

Application-Specific Testing Capabilities Across Industries

The selection of a surge generator is often dictated by the specific requirements of the target industries. Both systems are applicable across a broad spectrum, but their features may be more or less advantageous depending on the context.

• Lighting Fixtures & Household Appliances: For mass-produced consumer goods, testing efficiency is critical. The LISUN SG61000-5’s integrated design allows for rapid setup and high-throughput testing of products like LED drivers, smart home hubs, and washing machine control boards, directly applying surges to AC power ports as per IEC/EN 61000-4-5.
• Industrial Equipment & Power Tools: These devices often operate in harsh electrical environments with large inductive motors. Testing requires robust CDNs capable of handling high inrush currents. Both LISUN and Haefely offer solutions, but the integrated high-current CDN of the SG61000-5 (100A) simplifies testing against standards like IEC 61000-6-2.
• Medical Devices & Automotive Electronics: These sectors demand extreme reliability. Testing must include not only power lines but also communication and signal lines (e.g., CAN bus, Ethernet). The modular nature of Haefely systems allows for the seamless integration of specialized CDNs for non-power ports. The LISUN SG61000-5 can achieve this with external accessories, a common practice for both integrated and modular systems when testing to standards like ISO 7637-2 (automotive) or IEC 60601-1-2 (medical).
• Rail Transit, Aerospace, and Power Equipment: These high-reliability sectors often reference more stringent or specialized standards. Haefely’s long-standing reputation and modular flexibility are frequently specified. However, the LISUN SG61000-5, with its compliant waveforms and high-voltage/current capabilities, presents a technically valid and cost-effective solution for many of the surge tests required in these industries.

Waveform Accuracy and Calibration Traceability

The ultimate measure of a surge generator’s quality is the accuracy and repeatability of its output waveform. Both manufacturers design their equipment to remain within the tolerances specified by the IEC standard, which are typically ±10% for peak voltage and ±20% for front and tail times. Maintaining this accuracy over time requires regular calibration using a calibrated oscilloscope and a high-voltage differential probe or a dedicated current and voltage sensor.

Haefely equipment is renowned for its precision and long-term stability, backed by comprehensive calibration certificates traceable to national metrology institutes. This historical reliability is a key factor for accredited laboratories whose quality systems demand stringent measurement uncertainty budgets. LISUN, as a growing force in the market, also provides calibration traceability and emphasizes the stability of its components. For many compliance labs, especially those performing testing to commercial standards, the waveform accuracy of a modern integrated system like the SG61000-5 is more than sufficient and is verified during initial installation and periodic calibration.

Control Software and System Integration in Modern Test Laboratories

Modern EMC test facilities rely on software for test sequencing, data logging, and report generation. Haefely systems are typically controlled by sophisticated, dedicated software packages like AMETEK® CTS’ EMQST, which can orchestrate complex, multi-standard test sequences across various instruments from the same vendor. This level of integration is powerful for large, automated test stands.

The LISUN SG61000-5 is designed to be controlled via its intuitive touchscreen or through remote commands sent via SCPI (Standard Commands for Programmable Instruments) over Ethernet or GPIB. This allows for easy integration into custom software environments or third-party test executive platforms. This approach offers flexibility for labs that use equipment from multiple vendors or have specific software requirements, potentially reducing the cost and complexity associated with proprietary software licenses.

Economic and Operational Considerations for Compliance Laboratories

The total cost of ownership extends beyond the initial purchase price. Key considerations include:

• Capital Investment: Integrated systems like the LISUN SG61000-5 typically present a lower initial capital outlay, as the CDN and control system are included. Modular Haefely systems, while potentially more expensive initially, offer a “pay-as-you-grow” model.
• Operational Efficiency: The plug-and-play nature of an integrated system reduces setup time and operator training, increasing throughput. Modular systems may require more expert configuration but offer unparalleled flexibility for non-standard tests.
• Maintenance and Service: Haefely has a global service and support network befitting its long-established position. LISUN has been rapidly expanding its international support and service capabilities. Service contract costs and mean time to repair are critical factors for labs where instrument downtime directly impacts revenue.
• Longevity and Upgrade Path: Modular systems have a distinct advantage in longevity, as individual components can be upgraded. An integrated system is typically replaced as a whole when it becomes obsolete or requires a major upgrade.

Conclusion: Selecting the Appropriate Surge Test Solution

The choice between a LISUN SG61000-5 and a Haefely surge test system is not a matter of identifying a superior product, but rather of selecting the most appropriate tool for a specific laboratory’s requirements. Haefely represents the benchmark in modular, high-precision, and flexible test equipment, ideally suited for large, accredited laboratories that require maximum configurability and have a need to adhere to a wide array of evolving and specialized standards.

The LISUN SG61000-5 Surge Generator embodies a modern, integrated approach that prioritizes ease of use, space efficiency, and cost-effectiveness without compromising on fundamental compliance with key international standards. It represents a compelling solution for R&D departments, third-party testing labs focused on high-volume consumer and industrial goods, and educational institutions where operational simplicity and a lower total cost of ownership are significant advantages. For a vast majority of applications spanning from household appliances to industrial equipment, the technical performance of the SG61000-5 is fully capable of delivering accurate, repeatable, and standards-compliant surge immunity test results.

Frequently Asked Questions (FAQ)

Q1: Can the LISUN SG61000-5 be used for testing surge immunity on communication ports, such as Ethernet or RS485?
Yes. While the main unit includes an integrated CDN for power lines, the system is designed to work with external coupling networks for signal and communication lines. These external networks are used to apply the surge stress to the data lines while preventing the surge energy from propagating back into the auxiliary equipment or the laboratory’s power grid, in accordance with IEC 61000-4-5.

Q2: How does the selectable source impedance (2Ω vs. 12Ω) function, and when is each setting used?
The internal impedance of the generator is part of the wave-shaping network that defines the current delivered into a short circuit. The 2 Ω impedance is the standard value for testing power ports according to IEC 61000-4-5. The 12 Ω impedance is required by certain telecommunications and signaling standards to simulate the characteristic impedance of longer lines. The SG61000-5 allows the operator to select the appropriate impedance for the standard being applied.

Q3: What is the significance of phase angle synchronization for AC power line testing?
Phase synchronization allows the surge to be injected at a specific point on the AC voltage waveform (e.g., at the 90-degree peak). This is critical for repeatability, as the susceptibility of a device’s power supply can vary dramatically depending on whether the surge occurs at the peak or the zero-crossing of the AC cycle. Reproducible testing requires controlling this variable.

Q4: Is the LISUN SG61000-5 suitable for testing equipment according to automotive standards like ISO 7637-2?
The SG61000-5 is capable of generating the required pulses for ISO 7637-2, such as Pulse 5a (load dump simulation). However, ISO 7637-2 specifies unique waveforms and test setups that may require additional external components or specific coupling methods. The generator provides the foundational capability, but the test setup must be configured to the exact requirements of the automotive standard.

Q5: What is the typical calibration interval for a surge generator, and what does calibration involve?
The calibration interval is typically one year, as recommended by most quality standards (e.g., ISO 17025). Calibration involves verifying the accuracy of the output voltage and current waveforms using a calibrated measuring system (oscilloscope and sensors). The rise times, durations, and peak values are measured under open-circuit and short-circuit conditions to ensure they remain within the tolerances specified by the IEC standard.