Product Introduction

Currently, conventional QJ44-type double-arm DC bridges are widely used within power systems to measure loop contact resistance. However, the test current generated by these bridges is merely in the milliampere (mA) range, making it difficult to detect defects involving a reduction in the cross-sectional area of loop conductors. Furthermore, when utilizing standard high-precision loop contact Resistance Testers, the presence of oil films and oxide layers between contact points can cause measured values to be several times higher than actual figures, thereby failing to accurately reflect the true contact resistance value. Consequently, the Ministry of Electric Power's standard SD301—88, *Regulations for Commissioning and Preventive Testing of AC 500kV Power Equipment*, along with the latest edition of the *Regulations for Preventive Testing of Power Equipment*, now mandate that the test current for measuring the contact resistance of circuit breakers and disconnectors must be no less than 100A DC to ensure the accuracy of test results.

The HCHL-200B High-Precision Loop Contact Resistance Tester is designed in strict accordance with the latest power industry execution standard of the People's Republic of China, DL/T845.4-2004. It integrates advanced high-frequency switching power supply technology with digital circuit technology. This high-precision tester is specifically designed for measuring the loop resistance of switch control equipment. It utilizes DC test currents of 100A and 200A—values recommended by national standards. The device allows for the direct measurement of loop resistance at current levels of 100A and 200A; the final test results are displayed on a large-screen LCD, and the unit features additional functions such as data storage, print output, and time setting capabilities. Furthermore, 50A and 150A current ranges are available for user selection. Characterized by its measurement accuracy and stable performance, this high-precision loop contact resistance tester fully meets the requirements of power utilities and supply departments for on-site maintenance of high-voltage switches, as well as the testing requirements of high-voltage switch manufacturers.

Product Aliases: High-Precision Loop Resistance Tester, High-Precision Contact Resistance Tester, Contact Resistance Tester, Loop Resistance Tester

Technical Parameters

Product Features

1. High Current Output: This high-precision loop contact resistance tester employs the latest power supply technology to deliver a continuous, high-magnitude current over extended periods. By overcoming the limitations of transient currents inherent in pulse-type power supplies, it effectively breaks down oxide films on switch contacts, thereby ensuring highly accurate test results.

2. High Stability: Even under conditions of severe electromagnetic interference, the least significant digit displayed on the LCD screen remains stable within a range of ±1 digit, ensuring stable readings and excellent repeatability.

3. High Accuracy: Utilizing dual-channel, high-speed 16-bit Σ-Δ AD sampling and the latest digital signal processing technology, the device achieves a maximum resolution of 0.01 μΩ. It is currently the only contact resistance tester available domestically that offers both a 0.01 μΩ resolution and exceptional stability, surpassing the performance of imported high-current micro-ohmmeters.

4. Intelligent Operation: Equipped with an imported, high-performance CPU, the system automatically switches measurement ranges based on signal magnitude during testing, thereby guaranteeing the accuracy of the results. An integrated over-temperature protection circuit automatically cuts off the output current if the instrument exceeds a preset temperature threshold, ensuring safe operation.

5. High Quality: All critical components are sourced from international manufacturers. A cleverly designed temperature compensation circuit effectively eliminates the influence of ambient temperature on measurement results, while the use of military-grade connectors enhances the instrument's vibration resistance.

6. Powerful Functionality: The test current can be freely selected from 50A, 100A, 150A, or 200A, and the test duration can be arbitrarily set between 5 seconds and 599 seconds. This overcomes the limitations found in similar instruments—such as the inability to set measurement duration or excessively short continuous operation times—and significantly outperforms other devices in its class.

7. User-Friendly Interface: Data input is performed via a rotary "mouse" control, offering a convenient and rapid method for configuration. Users can independently set the instrument's date and time, save measurement data in real-time, and instantly print test results.

8. Multiple Communication Options: The device supports communication with a computer via an RS232 serial port (9-pin) or a USB data cable, allowing measurement data to be uploaded for further analysis and processing by test personnel.

9. Ease of Use: The high-precision loop contact resistance tester features a compact size and lightweight design, making it highly portable and convenient for field use.