Loop Resistance Tester Dynamics
1. High Current: The high-precision loop resistance tester uses the latest power supply technology, capable of continuously outputting high current for a long time, overcoming the drawbacks of instantaneous current from pulse power supplies, effectively breaking through the oxide film on switch contacts, and obtaining good test results.
Results
2. High Stability: Under severe interference conditions, the last digit of the LCD screen can stabilize within ±1 digit, with stable readings and good repeatability
3. High Precision: Using dual-channel high-speed 16-bit Σ－ΔAD sampling and the latest digital signal processing technology, the maximum resolution reaches 0.01μΩ, making it a contact resistance tester that can achieve 0.01μΩ resolution and is very stable, with performance exceeding imported high-current micro-ohmmeters
4. Intelligence: Using an imported high-performance CPU, the system automatically switches ranges based on signal strength during measurement, ensuring the accuracy of the product. Over-temperature protection circuit can automatically stop output current when the instrument exceeds the set temperature, ensuring safe use of the instrument
5. High Quality: All key components are imported, and the cleverly designed temperature compensation circuit effectively eliminates the influence of ambient temperature on measurement results. The use of military-grade connectors enhances vibration resistance
6. Powerful Functionality: Current can be freely selected among 50A, 100A, 150A, and 200A, and test time can be set arbitrarily from 5s to 599s, overcoming the defects of other similar instruments that cannot set measurement time or have too short continuous working time, far exceeding the performance of other similar instruments
7. Friendly Human-Machine Interface: Data input via rotary mouse is convenient and fast, allowing users to set the instrument date and time, save measurement data in real-time, and print measurement results immediately
8. USB Transfer: Measurement data can be transferred to a USB drive via the USB interface, combined with host computer software for further analysis and processing of measurement data
9. Easy to Use: Small size, light weight, and portable
Product Introduction
Currently, the conventional QJ44 type double-arm DC bridge is commonly used in power systems to measure contact resistance, but the test current of such bridges is only at the mA level, making it difficult to detect defects of reduced cross-sectional area in loop conductors. When measuring the contact resistance of high-voltage switch conductive loops, due to the influence of oil film and oxide layer between contacts, the measured value is several times larger, failing to truly reflect the contact resistance value. Therefore, the latest Ministry of Electric Power standard DL/T845.4—2004 "General Technical Conditions for Resistance Measuring Devices: Loop Resistance Testers" and the new verification regulation JJG1052-2009 "Verification Regulation of Loop Resistance Testers and DC Resistance Testers" stipulate that the measurement current for contact resistance of (isolating) switches, circuit breakers, etc., should not be less than DC 100A, and the minimum current maintenance time should not be less than 60 seconds, ensuring accurate test results.
The operation panel of this instrument adopts ergonomic design, conforming to operating habits, and uses high-frequency switching power supply and digital circuit technology, suitable for measuring the loop resistance of switch control equipment. The test current adopts DC 100A and 200A recommended by national standards. The loop resistance can be directly measured under DC 100A and 200A, and the test results are displayed on a large-screen LCD, with functions such as data storage, output printing, and time setting. Additionally, 50A and 150A gears are available for user selection; the test time can be customized, with a maximum setting time of 599S, greater than the 60S specified by the standard; it can achieve 0.01μΩ resolution and is a very stable contact resistance tester, with performance exceeding imported high-current micro-ohmmeters. It meets the requirements for on-site high-voltage switch maintenance and loop resistance testing in power and power supply departments and high-voltage switch factories.
