Research on the Application of AC/DC Withstand Voltage Test in High-Voltage Safety Detection of Electrical Products

Abstract
Insulation performance of electrical products is the core foundation to ensure power consumption safety and stable equipment operation. As a key technical method for high-voltage safety detection, AC/DC withstand voltage test is widely applied in quality inspection and compliance verification of household appliances, lighting products, industrial equipment, medical devices and other fields. This paper expounds the basic principle and detection value of AC/DC withstand voltage test. Taking LISUN WB2671B AC/DC Withstand Voltage Tester as the research carrier, it analyzes the technical parameters, core functions and application scenarios of the equipment, and discusses the practical effect of AC/DC withstand voltage test in identifying hidden dangers such as insulation damage and circuit short circuit. It provides reference for the standardized and accurate implementation of high-voltage safety detection of electrical products.

1. Introduction
With the rapid development of electrical and electronic products towards miniaturization, intelligence and high power, the internal insulation structure of products becomes increasingly sophisticated and complex. Insulation layer aging, damage, insufficient creepage distance and local circuit short circuit are easy to occur during long-term operation, which will cause equipment failure and shutdown in light cases, and lead to electric leakage, electric shock, fire and other safety accidents in severe cases. According to statistics on electrical safety accidents, more than 60% of civil and industrial electrical safety accidents are caused by unqualified insulation performance. Therefore, strict high-voltage safety detection has become an essential link in factory quality inspection, type certification and daily operation and maintenance of electrical products.

AC/DC withstand voltage test is the core item of electrical high-voltage safety detection. Different from ordinary insulation resistance test, this test applies AC or DC high voltage far exceeding the rated working voltage to the Device Under Test (DUT), and accurately monitors breakdown leakage current synchronously, so as to intuitively evaluate the insulation material tolerance capacity and breakdown resistance limit of the equipment, and accurately find hidden insulation defects. At present, a complete standard system has been formed in the industry. Domestic and international standards such as GB 4706.1, IEC 60335-1 and GB 7000.1 clearly stipulate that all kinds of electrical products must pass the AC/DC withstand voltage test. As a professional AC/DC withstand voltage tester, LISUN WB2671B accurately meets the detection demands of various types of electrical products, taking into account the batch detection efficiency of production lines and the precision of laboratory compliance detection, and has become the core equipment for the practical application of AC/DC withstand voltage test.

2. Basic Principle and Detection Significance of AC/DC Withstand Voltage Test

2.1 Basic Principle
AC/DC withstand voltage test is divided into AC withstand voltage test and DC withstand voltage test. Although there are slight differences in principles, the core logic remains consistent. The AC withstand voltage test simulates the actual power frequency operating voltage condition of electrical products, and applies 50Hz power frequency AC high voltage, which is in line with the real power consumption environment of equipment, and can effectively find concentrated insulation defects, air gap discharge and creepage faults. The DC withstand voltage test outputs stable DC high voltage, featuring lightweight test equipment, little damage to insulation and easy positioning of local defects. It is suitable for the detection of capacitive components, lamp housings, high-voltage cables and other products.

During the test, the tester steadily boosts the voltage to the target value according to preset parameters and maintains it for a specified period, and collects real-time leakage current values in the loop. If the insulation performance is qualified, the leakage current will stay within the standard limit without breakdown or flashover. If there are problems such as damage, aging and short circuit in insulation, the leakage current will rise sharply, triggering over-current protection and sound-light alarm of the equipment, and judging the product unqualified.

2.2 Core Detection Significance
• Eliminate potential safety hazards: Accurately identify hidden defects such as insulation layer damage, winding short circuit, insufficient creepage distance and failure of component withstand voltage, and avoid electric leakage and electric shock risks from the source.
• Meet compliance certification requirements: Satisfy the requirements of national standards and international IEC standards for household appliances, lighting, medical treatment, industrial equipment and other industries, and serve as a mandatory detection item for product market access and third-party certification.
• Realize quality grade judgment: Quantitatively evaluate the tolerance strength of insulation materials, and provide data support for product design optimization, raw material selection and production process improvement.
• Predict service life and guide operation & maintenance: Detect the insulation aging degree of in-service electrical equipment through AC/DC withstand voltage test, predict the service life of equipment in advance, and formulate reasonable operation, maintenance and replacement plans.

WB2671B AC/DC Withstand Voltage Test

3. Parameter and Functional Characteristics of LISUN WB2671B AC/DC Withstand Voltage Tester

3.1 Specification Parameters of Series Products
The LISUN WB267* series includes multiple models with AC/DC compatible mode and pure AC high voltage mode, which meet the demands of different scenarios for AC/DC withstand voltage test. The key parameters of core models are shown in the table below:

It can be seen from the table that WB2671B supports full-range AC/DC test voltage from 0 to 5KV, with AC breakdown current up to 100mA and transformer capacity of 500VA, which is superior to WB2671A in the same series. It is applicable to both conventional detection with small current and withstand voltage test of medium-power products. The adjustable test time from 1 to 99 seconds and ±5% measurement accuracy can meet the AC/DC withstand voltage test standard requirements of most civil and small industrial products.

3.2 Core Functional Characteristics
The WB2671B is specially developed for AC/DC withstand voltage test of electrical products, with functional design fully fitting the actual demands of industrial detection:
• Dual-mode switching for AC and DC: One-click switching between AC and DC test modes, realizing AC working condition simulation and accurate DC withstand voltage detection without equipment replacement, suitable for various types of products.
• Intelligent preset and precise regulation: Support preset test voltage and withstand voltage duration with continuously adjustable voltage, complying with test threshold requirements of GB, IEC and other different standards.
• Multiple safety protection mechanisms: Equipped with rapid over-current protection, automatic discharge after test and high voltage warning function to eliminate potential operation safety hazards caused by residual high voltage. Sound-light alarm will be triggered automatically for unqualified results with clear detection results.
• Strong operation adaptability: Equipped with local key operation and remote control interface with simple and intuitive interface, suitable not only for rapid batch detection on production lines, but also for refined compliance verification in laboratories.
• Wide compatibility: It can be used for various products such as small household appliances, lighting products, electronic components and small industrial equipment, and can directly complete AC/DC withstand voltage test without additional modification.

4. Application Scenarios of AC/DC Withstand Voltage Test and WB2671B Tester

4.1 Detection of Civil Small Household Appliances and Lighting Products
Small household appliances are the most widely applied field of AC/DC withstand voltage test. In accordance with GB 4706.1-2024 and IEC 60335-1:2023 standards, power cords and internal windings of electric rice cookers, electric kettles, induction cookers and other products need to pass AC 1500~2500V AC withstand voltage test. For LED downlights, ceiling lights, panel lights and other lighting products, DC 2000~3000V DC withstand voltage test shall be carried out between lamp holders and metal shells to verify insulation isolation performance. With 5KV AC/DC voltage output and 100mA large AC current range, WB2671B can perfectly meet the batch detection demands of such products.

4.2 Detection of Electronic Components
The insulation reliability of basic electronic components such as capacitors, small relays, transistors and winding coils directly affects the safety of complete equipment. In accordance with GB/T 14472-2017 and IEC 60831-1:2017 standards, AC/DC withstand voltage test of AC 1000~2000V shall be conducted between component windings to find hidden dangers such as inter-turn insulation damage and electric leakage. The 20mA DC current range of WB2671B can accurately capture weak leakage current of components and judge withstand voltage reliability precisely.

4.3 Detection of Small Industrial and Special Electrical Equipment
Control boxes for machine tools, small frequency converters, air conditioner outdoor unit motors, washing machine drive motors and other industrial and high-power household electrical equipment need to pass AC 3000~5000V AC/DC withstand voltage test in accordance with GB/T 24344-2009 and GB 19212.1-2021 standards to detect the insulation performance between equipment cabinet and internal circuits as well as motor windings to the ground. With strong load-bearing capacity supported by 500VA transformer capacity, WB2671B can maintain stable high voltage output and adapt to the detection of such medium-power industrial products.

4.4 Extended Application on Medical and High-Voltage Lighting Equipment
For outdoor high-voltage floodlights, small medical diagnostic instruments, high-voltage physical therapy equipment and other products that require 10KV high voltage test, the WB2672A model can be selected. While the conventional power modules and control circuits can complete AC/DC withstand voltage test by WB2671B, satisfying GB 9706.1-2020 medical device safety standards and national standards for lamps.

5. Implementation Key Points and Quality Control of AC/DC Withstand Voltage Test
To ensure accurate and reliable results of AC/DC withstand voltage test, combined with the operation specifications of WB2671B, three key points shall be controlled during test implementation:
• Standardized parameter setting: Set test voltage, withstand voltage duration and leakage current threshold strictly in accordance with corresponding national standards and IEC standards of products, and shall not lower the test standards arbitrarily. The standard withstand voltage duration for conventional products is set to 60 seconds uniformly.
• Test environment control: Keep the test environment temperature at 20~25℃ and relative humidity at 45%~75%. Avoid misjudgment of insulation performance caused by humid and dusty environment, and clean surface stains and moisture of tested products before test.
• Regular equipment calibration and maintenance: The WB2671B shall be calibrated annually to ensure that the measurement accuracy of voltage and current is within the allowable error range of ±5%. Perform automatic discharge after test, and regularly check the integrity of insulation of high-voltage output lines.

Meanwhile, testers must strictly abide by high-voltage operation specifications, wear insulating protective equipment, and reduce close contact with high voltage by using the remote control function of equipment to avoid operation safety risks.

6. Conclusion
AC/DC withstand voltage test is an indispensable core technology in high-voltage safety detection of electrical products. By applying AC and DC high voltage and monitoring leakage current, it can accurately evaluate the insulation strength and breakdown resistance of tested equipment, effectively eliminate hidden safety hazards such as insulation damage and circuit short circuit, and serve as a key means to guarantee the quality safety of electrical products and meet industrial compliance standards.

Supported by wide voltage range of 0~5KV AC/DC, multi-range current detection, intelligent protection and convenient operation, LISUN WB2671B AC/DC withstand voltage tester perfectly meets the AC/DC withstand voltage test demands of small household appliances, lighting products, electronic components, small industrial equipment and other products, balancing the batch production detection efficiency and laboratory precise verification requirements. In the future, with the continuous upgrading of safety standards for electrical products, AC/DC withstand voltage test will develop towards intelligence, automation and high precision. Withstand voltage test equipment will further optimize functions such as remote measurement and control, data storage and batch linkage detection, laying a solid technical foundation for the safe and high-quality development of the electrical industry.