Hipot Test: Application of LISUN HIPOT10-100KV AC/DC Hipot Tester in Capacitor Withstand Voltage Testing

Abstract
Hipot Test, short for high potential test, is a critical electrical safety test designed to evaluate the insulation strength of electrical components by applying a higher-than-rated voltage for a specified duration. For capacitors, which are widely used in power systems, electronic devices, and industrial equipment, ensuring robust insulation performance through Hipot Test is essential to prevent insulation breakdown, short circuits, or even catastrophic failures. This paper focuses on the application of AC/DC hipot testers, particularly the LISUN HIPOT10-100KV model, in capacitor withstand voltage testing. It elaborates on the working principle of Hipot Test, details the specifications of the LISUN HIPOT10-100KV AC/DC Hipot Tester, and discusses its practical operation and advantages in capacitor testing. The analysis confirms that the LISUN HIPOT10-100KV, with its reliable performance and flexible AC/DC output, serves as an ideal tool for ensuring the safety and durability of capacitors in various industrial scenarios.

Keywords
Hipot Test; AC/DC Hipot Tester; capacitor withstand voltage test; LISUN HIPOT10-100KV; insulation strength

1. Introduction
Capacitors play a pivotal role in energy storage, power factor correction, and voltage regulation in electrical systems. Their insulation performance directly determines the stability and safety of the entire system. A capacitor with inadequate insulation may suffer from breakdown under operating voltage, leading to equipment damage, energy loss, or even fire hazards. To avoid such risks, the Hipot Test has become an indispensable procedure in capacitor manufacturing, quality control, and maintenance.

The Hipot Test involves applying an AC or DC voltage significantly higher than the component’s rated operating voltage for a predetermined period (typically 1 minute) to check for insulation breakdown or excessive leakage current. For capacitors, this test verifies whether their dielectric materials can withstand overvoltage conditions without failure. Among the various hipot testing devices available, the LISUN HIPOT10-100KV AC/DC Hipot Tester stands out for its versatility, reliability, and suitability for high-voltage capacitor testing. This paper explores the principles of Hipot Test, the technical specifications of the LISUN HIPOT10-100KV, and its practical application in capacitor withstand voltage testing.

2. Principles of Hipot Test for Capacitors

2.1 Fundamental Concept of Hipot Test

The core principle of Hipot Test is to assess the insulation integrity of a capacitor by exposing it to a controlled high voltage. Unlike routine continuity tests, which check for low-resistance paths, the Hipot Test focuses on the insulation’s ability to resist high potential differences. For capacitors, the test voltage is usually set to 1.5 to 2 times the rated voltage, depending on industry standards (e.g., IEC 60252 for power capacitors). If the insulation is defective, the test will detect excessive leakage current or a sudden drop in voltage, indicating a breakdown.

2.2 Working Principle of LISUN AC/DC Hipot Tester

The LISUN HIPOT series, including the HIPOT10-100KV model, operates on a well-designed mechanism to ensure accurate and safe Hipot Test execution. Its working principle involves three key components:
• Auto-voltage Regulator: This component adjusts the input voltage to the high-voltage test transformer, allowing precise control of the output voltage within the rated range. For the HIPOT10-100KV, the regulator enables smooth adjustment from 0 to the maximum output voltage (100kV AC or 140kV DC).
• High-voltage Test Transformer: It converts the low input voltage (e.g., 200V for HIPOT10-100KV) into the high voltage required for the test. The transformer’s design ensures stable output even under varying load conditions, critical for accurate capacitor testing.
• Control Cabinet: Equipped with a high-voltage output voltmeter, a low-voltage input ammeter, and an overcurrent protection circuit, the cabinet provides real-time monitoring of test parameters. The overcurrent protection triggers immediately if leakage current exceeds the safe threshold (e.g., 100mA AC for HIPOT10-100KV), 切断电源 to prevent damage to the capacitor or tester.

HIPOT10-100KV_AC/DC Hipot Tester

3. Technical Specifications of LISUN HIPOT Series, with Focus on HIPOT10-100KV
LISUN offers a range of AC/DC Hipot Testers tailored for different testing requirements. Table 1 presents the key specifications of selected models, with emphasis on the HIPOT10-100KV, which is widely used for high-voltage capacitor testing.
Table 1: Technical Specifications of LISUN HIPOT Series AC/DC Hipot Testers

3.1 Key Features of HIPOT10-100KV for Capacitor Testing

The HIPOT10-100KV is specifically engineered to meet the demands of high-voltage capacitor testing, with the following standout features:
• Dual Voltage Output: It supports both AC (100kV) and DC (140kV) testing, making it suitable for different types of capacitors (e.g., AC film capacitors and DC electrolytic capacitors).
• Adequate Capacity: With a 10kVA capacity, it can handle the power requirements of medium to large capacitors, ensuring stable voltage output during prolonged tests.
• Precise Current Monitoring: The AC output current (100mA) and DC output current (50mA) limits are optimized to detect subtle leakage currents in capacitors, providing accurate pass/fail judgments.
• Safety Design: The 200V input voltage and 50A input current are compatible with standard industrial power supplies, while the built-in overcurrent protection ensures operator and equipment safety.

4. Application of LISUN HIPOT10-100KV in Capacitor Hipot Test

4.1 Test Preparation

Before conducting the Hipot Test on a capacitor using the HIPOT10-100KV, several preparatory steps are essential:
• Equipment Inspection: Verify that the tester is calibrated (per ISO 9001 standards) and that all cables, connectors, and insulation components are in good condition.
• Capacitor Preparation: Discharge the capacitor completely to eliminate residual charge, which could interfere with test results or cause arcing.
• Connection Setup: Connect the capacitor’s terminals to the tester’s high-voltage output and ground. For AC testing, ensure the capacitor is compatible with alternating current to avoid dielectric heating issues; for DC testing, confirm polarity to prevent reverse breakdown.

4.2 Test Procedure

The Hipot Test using HIPOT10-100KV follows a systematic process to ensure reliability:
• Parameter Setting: Power on the tester and select AC or DC mode based on the capacitor’s specifications. Set the test voltage (e.g., 120kV AC for a capacitor with a rated voltage of 80kV) and the test duration (typically 60 seconds).
• Voltage Ramp-Up: Gradually increase the voltage from 0 to the set value at a steady rate (e.g., 5kV/s) to avoid dielectric stress from sudden voltage spikes.
• Monitoring: During the test, observe the voltmeter and ammeter on the control cabinet. A stable voltage and leakage current below the threshold (100mA AC for HIPOT10-100KV) indicate normal insulation.
• Voltage Ramp-Down: After the test duration, reduce the voltage to 0 before disconnecting the capacitor to prevent arcing.
• Result Evaluation: A capacitor passes the Hipot Test if no breakdown, flashover, or excessive leakage current is detected. Failed units are marked for rework or rejection.

4.3 Advantages in Capacitor Testing

The LISUN HIPOT10-100KV offers several advantages for capacitor Hipot Test:
• High Versatility: Its AC/DC dual-mode capability allows testing of both polar (e.g., electrolytic) and non-polar (e.g., film) capacitors.
• Reliable Performance: The compact structure and robust components ensure consistent results even in industrial environments with temperature or humidity variations.
• Efficiency: The simple operation interface and quick voltage adjustment reduce test time, making it suitable for high-volume capacitor production lines.

5. Discussion
The Hipot Test is indispensable for validating capacitor insulation, and the choice of tester directly impacts test accuracy and safety. The LISUN HIPOT10-100KV, with its 100kV AC and 140kV DC output, fills a critical gap in high-voltage capacitor testing, where lower-capacity testers may fail to reach required voltages.

Compared to other models in the LISUN series, the HIPOT10-100KV balances capacity and portability. For example, while the HIPOT50-100KV offers higher capacity (50kVA), it requires a 380V input, limiting its use in facilities with standard 200V power. The HIPOT10-100KV, by contrast, is more adaptable to diverse industrial settings.

Notably, the tester’s compliance with international safety standards (e.g., IEC 61010 for electrical test equipment) ensures that test results are recognized globally, facilitating cross-border capacitor trade.

6. Conclusion
The Hipot Test is a cornerstone of capacitor quality assurance, and the LISUN HIPOT10-100KV AC/DC Hipot Tester emerges as a superior tool for this application. Its precise voltage control, reliable protection mechanisms, and versatile specifications make it ideal for evaluating the insulation strength of high-voltage capacitors. By ensuring that capacitors can withstand overvoltage conditions, the HIPOT10-100KV contributes to the safety and longevity of electrical systems.

As capacitor technology advances toward higher voltages and miniaturization, the role of advanced Hipot Test equipment like the LISUN HIPOT10-100KV will only grow, underscoring its significance in modern electrical engineering and manufacturing.