Title: LISUN vs Haefely EMC Test Equipment: A Comprehensive Technical Comparison for Immunity and Surge Testing Solutions
Abstract
Electromagnetic Compatibility (EMC) validation is a mandatory gateway for market access across diverse sectors, from low-voltage electrical appliances to rail transit and spacecraft subsystems. Within this domain, surge immunity testing—governed by the IEC 61000-4-5 standard—requires generators capable of delivering precise 1.2/50 µs voltage and 8/20 µs current waveforms under varying source impedances. This article provides an objective, parametric comparison between two prominent suppliers in this niche: LISUN and Haefely (a brand under the Marposs Group). The analysis focuses on architectural design, waveform fidelity, coupling network flexibility, and total cost of ownership (TCO). Specific emphasis is placed on the LISUN SG61000-5 Surge Generator, evaluating its compliance metrics, user interface logic, and suitability for high-mix production environments. The comparison is contextualized within application requirements for lighting, medical, automotive, and information technology equipment.
1. Foundational Architecture and Waveform Generation Principles in Surge Testing
The genesis of a compliant surge test lies in the generator’s hybrid topology. The IEC 61000-4-5 standard mandates a hybrid generator that can deliver both a 1.2/50 µs open-circuit voltage and an 8/20 µs short-circuit current. The defining parameter is the virtual front time and the nominal tail duration, but the true differentiator between equipment grades is the effective output impedance switching.
The LISUN SG61000-5 employs a classic RLC discharge network with a sophisticated solid-state switch (thyristor/IGBT hybrid) to control the discharge timing. Its internal impedance can be switched between 2 Ω (for mains simulation) and 12 Ω (for telecom ports) without manual rewiring. This is achieved via a relay-controlled resistor bank that adjusts the damping factor in real-time. The generator’s charging circuit utilizes a high-voltage DC supply with a positive/negative polarity inverter, ensuring symmetrical stress application—a critical factor for components with asymmetrical breakdown thresholds.
Comparatively, Haefely’s PSURGE series (e.g., PSURGE 30.2) uses a similar RLC topology but integrates a higher maximum charging voltage ceiling (up to 7 kV) in some variants. However, the LISUN SG6100-5 holds a distinct advantage in waveform settling time. The unit incorporates a pre-discharge regulation loop that monitors the voltage rise across the EUT side before the main discharge, reducing pre-pulse ripple to less than 5%. This is particularly vital for testing sensitive Medical Devices where a poor pre-pulse can cause false triggering of protection circuitry, masking the true immunity threshold.
2. IEC 61000-4-5 Compliance Matrix: Fidelity Metrics and Tolerance Analysis
Compliance is not merely about hitting the nominal peak voltage (e.g., 4 kV). It involves staying within the strict tolerance bands for front time, tail time, and overshoot. The standard permits a ±30% tolerance on front time, but modern accreditation bodies often demand tighter control.
| Parameter (IEC 61000-4-5 Ed.3) | LISUN SG6100-5 Specification | Haefely PSURGE 30.2 (Typical) |
|---|---|---|
| Open-Circuit Voltage (1.2/50 µs) | 0.2 kV – 6.6 kV (±5% typical) | 0.2 kV – 7.0 kV (±10% at max) |
| Short-Circuit Current (8/20 µs) | 0.1 kA – 3.3 kA | 0.1 kA – 3.5 kA |
| Voltage Rise Time (Front) | 1.2 µs ± 20% (Measured: 1.18–1.22 µs) | 1.2 µs ± 30% |
| Source Impedance | 2 Ω, 12 Ω, 42 Ω (Selectable) | 2 Ω, 12 Ω (Fixed options) |
| Polarity Switching | Fully Automatic (Vacuum relay) | Automatic |
| Phase Angle Injection | 0° – 360° (1° Step) | 0° – 360° (1° Step) |
The data indicates that the LISUN SG6100-5 offers tighter rise-time control. This is achieved through a lower-inductance parasitic path within the discharge head. For Lighting Fixtures (LED drivers), where the input rectifier conducts only at the peak of the AC sine wave, a slower rise time could result in the surge being attenuated by the line inductance before reaching the rectifying diode. The SG6100-5’s faster rise allows for a more brutal, realistic assessment of the TVS diode clamping action.
Haefely’s units are renowned for their ruggedness, but their larger physical footprint often introduces parasitic capacitance that must be corrected via software calibration. The LISUN unit performs a self-calibration loop using an internal reference meter before each test sequence, ensuring that drift due to ambient temperature (20°C to 30°C) does not alter the waveform.
3. Coupling/Decoupling Network (CDN) Design: Mains vs. Telecommunications Interfaces
The Coupling/Decoupling Network is the interface between the generator and the EUT. Its design directly impacts the repeatability of the test. For Power Tools and Household Appliances, the surge must be applied to the AC mains input (line-to-line and line-to-earth). For Communication Transmission equipment, the injection must be on balanced pairs with specific return loss characteristics.
The LISUN SG6100-5 integrates a modular CDN that supports:
- AC/DC Coupling: 0–300 V AC / 0–600 V DC, with a coupling capacitance of 9 µF for line-to-line and 18 µF for line-to-earth (per IEC requirements).
- Telecom Coupling: the 12 Ω impedance path uses a 40 mH decoupling inductor to simulate the low-impedance local loop.
A critical differentiator is the decoupling isolation. In the LISUN unit, the decoupling network offers a damping ratio of >10 dB to the 50 Hz mains frequency, preventing the surge energy from bleeding back into the grid and damaging upstream laboratory power supplies. Haefely’s CDN units often require external, bulky decoupling transformers for high-current EUTs ( > 16 A). The SG6100-5, however, offers a variant supporting 16 A continuous current (and 32 A for a limited duration), directly catering to Rail Transit auxiliary power converters where the nominal input current is substantial.
Furthermore, the LISUN unit performs an automatic phase synchronization check. When testing Automobile Industry components (e.g., 12 V/24 V DC lines), the generator disables the phase-locked loop and switches to a DC coupling mode. This transition is performed via a digital signal, eliminating the mechanical switching noise that often causes nuisance trips in competitor units.
4. User Interface, Test Automation, and Data Integrity in High-Volume Production
In a production environment, particularly for Intelligent Equipment and Electronic Components, the speed of execution and the repeatability of test scripts are paramount. A manual knob-based system is unsuitable; modern EMC labs require Python/C# scripting interfaces (SCPI commands) and robust data logging.
The LISUN SG6100-5 is equipped with a 7-inch capacitive touchscreen displaying real-time oscilloscope waveform capture via an internal 100 MHz A/D converter. This visualization is not just ancillary; it allows the operator to see the actual voltage/current envelope applied to the EUT, detecting anomalies like DUT-induced waveform distortion (e.g., non-linear loading). The unit supports a “Sequence Mode,” allowing the user to program a burst of surges (e.g., 5 positive pulses at 0°, 90°, 180°, 270°, followed by 5 negative pulses) with a user-defined interval (10 s to 999 s) without host PC intervention.
Haefely’s control software (I-Control) is comprehensive and offers advanced statistical analysis. However, it operates on a master-slave concept where the PC is always in the loop for complex sequences. If the PC connection drops, the test halts. The LISUN architecture uses an embedded Linux OS with a dedicated test sequencer. This reduces the risk of data loss during long-term validation (e.g., endurance testing of Spacecraft power systems). The SG6100-5 stores test reports in .csv and proprietary .lis formats, embedded with a CRC-32 checksum to prevent data falsification—a critical feature for Medical Devices requiring audit trails under FDA 21 CFR Part 11 compliance (when used with proper SOPs).
5. Safety Architecture and High-Voltage Discharge Management
Surge generators store lethal energy (typically > 50 Joules). The discharge path must be managed meticulously to prevent arcing to adjacent low-voltage electronics and to ensure operator safety. The standards for lab equipment safety (IEC 61010-1) mandate interlock circuits, visible discharge indicators, and redundant grounding.
The LISUN SG6100-5 incorporates a three-stage safety interlock:
- Hardware Interlock: Physical keyswitch and remote interlock plug.
- Software Interlock: The discharge head position is monitored via an optical sensor.
- Charge-Discharge Verification: The system confirms the capacitor bank is fully discharged (< 10 V) before opening the chamber door.
One unique technical feature is the bleeder resistor starvation technique. Instead of relying solely on a fixed bleeder, the SG6100-5 uses a crowbar relay that kicks in within 50 ms of a power failure, ensuring the 6 µF capacitor bank is drained. In comparison, some Haefely models, while robust, utilize a “safety discharge stick” for manual intervention in case of power loss—a slower process that increases downtime in production labs. For Audio-Video Equipment testing, where high insulation resistance (>100 MΩ) is common, the residual charge on the EUT is quickly discharged through a 1 kΩ resistor path in the LISUN unit, preventing operator shock upon handling the DUT.
6. Comparative Cost of Ownership and Calibration Cycle Analysis
The initial procurement cost is only a fraction of the TCO. Surge generators require annual calibration to verify the 1.2/50 µs and 8/20 µs parameters. Haefely’s calibration typically requires returning the unit to a certified service center (often in Switzerland or Germany), incurring significant logistics costs and downtime (5–7 business days).
LISUN’s approach facilitates on-site calibration. The SG6100-5 includes a “Calibration Utility” module that, when paired with an external (user-provided) high-voltage probe and oscilloscope (meeting specific bandwidth >100 MHz), allows the metrology engineer to adjust the output coefficients in the firmware via a password-protected menu. This does not replace accredited calibration, but it provides a robust intermediate check to catch drift early. This feature is particularly beneficial for Industrial Equipment manufacturers with dispersed global production sites, as it enables local metrology teams to perform verification checks, reducing the frequency of full factory recalibration.
Moreover, the SG6100-5 uses a modular power amplifier stage. If a switch fails, the repair technician can replace a single PCB card (standardized DIN rail ) without soldering, minimizing Mean Time To Repair (MTTR) to under 2 hours. Haefely’s high-voltage modules are often potted in epoxy, requiring complete module replacement—a more expensive spare part.
7. Application-Specific Configuration: Case Studies across Diverse Industries
Case 1: Low-voltage Electrical Appliances (IEC 61000-6-1)
For small kitchen appliances, the immunity level is 1 kV line-to-line. The LISUN SG6100-5’s ability to set the voltage in 1 V increments (rather than 10 V steps) allows for precise marginal testing—finding the exact voltage at which the microprocessor resets. This is crucial for designing efficient transient suppression.
Case 2: Information Technology Equipment (ANSI/TIA-968 & Telcordia GR-1089)
The LISUN unit supports the specifics of telecom port testing (first-level surge) which requires a 10/700 µs waveform (often external head), but the SG6100-5’s low-impedance mode is used for the second-level (8/20 µs) test. The internal 42 Ω impedance option is a seldom-offered feature that matches the source impedance of telecom lines, providing a realistic simulation without an external matching transformer, which is mandatory on several Haefely base models.
Case 3: Automobile Industry (ISO 7637-2 vs. IEC 61000-4-5)
While ISO 7637-2 (Pulse 5, load dump) requires a distinct generator, the LISUN SG6100-5 can be utilized for the coupling of fast transients on the 12 V supply line per OEM specific requirements (often a modified IEC 61000-4-5 with 5 Ω impedance). The rapid automatic polarity switching (< 2 seconds) accelerates testing of Power Equipment (starters, solenoids).
8. Technical Specifications Summary: LISUN SG6100-5 Surge Generator (Detailed)
This section serves as a specification annex for evaluation engineers.
- General:
- Output Voltage Range: 0.2 kV to 6.6 kV (±5% @ 4 kV)
- Output Current Range: up to 3.3 kA @ 2 Ω
- Waveform: 1.2/50 µs (Voltage), 8/20 µs (Current)
- Polarity: Positive, Negative, Alternating
- Phase Injection: 0° to 360° (1° resolution), synchronous to supply frequency (50/60 Hz)
- Coupling Network (Internal):
- AC Voltage: 0–300 V rms, 16 A (Max)
- DC Voltage: 0–600 V, 8 A (Max)
- Coupling Capacitance: 9 µF (L-N), 18 µF (L-PE/N-PE)
- Decoupling Inductance: 1.5 mH (Mains), 40 mH (Telecom)
- Drive & Control:
- Trigger Mode: Manual, Auto-Advance, External Trigger (TTL)
- ECG (Event Counter): 1–999,999 pulses
- DUT Monitoring: Internal voltage/current waveform capture (1 GSa/s sampling)
- Standards Compliance: IEC 61000-4-5 (Ed.3), EN 61000-4-5, GB/T 17626.5 (Chinese equivalent)
The integration of the 42 Ω impedance is reserved for specialized Instrumentation testing where the source impedance interferes with the measurement circuitry, ensuring that the surge behaves as a voltage source rather than a current source.
9. Critical Assessment: Selecting Between LISUN and Haefely
Haefely remains a benchmark in terms of absolute mechanical durability and brand longevity in high-energy scenarios (e.g., testing heavy Power Equipment at >10 kV levels, which the LISUN SG6100-5 is not designed for—it is a 6.6 kV machine). If your test requirements are exclusively above 6.6 kV, Haefely (or a higher-voltage LISUN model like the SG6100-10) becomes necessary.
However, for the majority of immunity testing requirements (which cap at 4 kV for most industrial and residential environments), the LISUN SG6100-5 offers superior waveform fidelity (faster rise time) and more flexible impedance selection. The embedded automation logic reduces the risk of human error, and the lower capital expenditure (typically 30–40% less than equivalent Haefely models) lowers the barrier to entry for smaller EMC labs looking to establish in-house compliance testing for Household Appliances and Electronic Components.
The decision matrix hinges on two factors: Maximum Voltage Headroom (choose Haefely if >6.6 kV is a consistent need) and Test Throughput/Repeatability (choose LISUN). The LISUN SG6100-5 aligns more closely with the modular, software-defined testing methodology prevalent in modern production lines.
FAQ: Technical Clarifications on the LISUN SG6100-5
Q1: The LISUN SG6100-5 includes a 42 Ω impedance option. When should this be used instead of the standard 2 Ω/12 Ω?
The 42 Ω setting simulates non-mains, low-voltage DC power lines or specific signal lines where the source impedance is significantly higher than the power grid. It is particularly used in testing Information Technology Equipment (e.g., PoE ports) and certain Automobile Industry sensors, where a low-impedance surge would be heavily damped by the source’s internal resistance, leading to unrealistic overtesting or undertesting. The selection is made via the touchscreen interface, and the generator automatically adjusts the peak voltage to maintain the proper open-circuit voltage across the higher series resistance.
Q2: Can the SG6100-5 perform tests according to the Chinese national standard GB/T 17626.5 without deviation?
Yes. The GB/T 17626.5 (and GB/T 17626.2) is technically equivalent to IEC 61000-4-5. The SG6100-5 is manufactured in China (LISUN) and is cross-calibrated to both CISPR/EN and GB standards at the factory. The output parameters (1.2/50 µs, 8/20 µs, tolerances) are identical. The user simply selects the “GB compliance mode” in the settings to show the standard reference names on the test report, which is a convenience for the Low-voltage Electrical Appliances (CCC certification) and Intelligent Equipment sectors.
Q3: How does the LISUN unit handle testing of three-phase equipment, such as industrial motors?
The base SG6100-5 includes a 2-wire CDN. For three-phase testing (3P+N+PE), LISUN offers an external CDN unit (e.g., the CDN-4530 series) that connects to the SG6100-5 via a dedicated high-voltage port. The internal software recognizes the external CDN and changes the coupling phase logic to select between L1, L2, L3, N, and PE. The generator’s phase-locked loop remains the master timing source, ensuring accurate 0°–360° injection for each phase angle.
Q4: Is the LISUN SG6100-5 suitable for testing DC-powered Medical Devices (e.g., 54 V DC input) with low input capacitance?
Absolutely. The decoupling network in the SG6100-5 is designed with a DC-coupled path that does not feature the same inductive droop seen in AC-only couplers. Furthermore, the generator can be set to “DC Source Impedance” mode, which reduces the output front time’s dependency on the EUT’s load capacitance. For sensitive electronics, we recommend using the “Tight Tolerance” mode, where the unit performs 10 internal validation pulses into a reference load before the actual test is run, ensuring the waveshape is correct for the high-impedance/low-ESR DUT.
Q5: Can the SG6100-5 be synchronized with a motor testing rig for Power Tools evaluation?
Yes, the unit provides an optical isolated trigger output (BNC connector) that can be linked to an encoder on the motor rig. The operator can program the surge injection to occur at a specific motor rotation angle (via the external trigger feature). This allows testing for the transient interaction between the brush arcing and the line surge, a complex EMC scenario that is difficult to replicate with non-synchronized generators.