JJG1052-2009 Loop Resistance Tester
Currently, in power systems, the conventional QJ44 type double-arm DC bridge is commonly used to measure contact resistance, but the test current of such bridges is only in the mA level, making it difficult to detect defects such as reduced cross-sectional area of 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. To this end, the latest Ministry of Electric Power standard DL/T845.4—2004 "General Technical Conditions for Resistance Measuring Devices: Loop Resistance Tester" and the new verification regulation JJG1052-2009 "Verification Regulation of Loop Resistance Tester and DC Resistance Tester" stipulate that the measurement current for contact resistance of measuring (isolating) switches, circuit breakers, etc., shall not be less than DC 100A, and the minimum current maintenance time shall 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 599 seconds, exceeding the standard requirement of 60 seconds; it is the only contact resistance tester in China that can achieve 0.01μΩ resolution and is very stable, with performance surpassing imported high-current micro-ohmmeters. It meets the requirements for on-site high-voltage switch maintenance in power and power supply departments and loop resistance testing in high-voltage switch factories.
1. High current: The high-precision loop resistance tester adopts the latest power supply technology, capable of continuously outputting large current for a long time, overcoming the drawbacks of instantaneous current in pulse power supplies, effectively breaking down the oxide film on switch contacts, and obtaining good test 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-Δ AD sampling and the latest digital signal processing technology, the maximum resolution reaches 0.01μΩ, making it the only contact resistance tester in China that can achieve 0.01μΩ resolution and is very stable, with performance surpassing imported high-current micro-ohmmeters.
4. Intelligent: Using an imported high-performance CPU, the system automatically switches ranges based on signal size during measurement, ensuring the accuracy of the product. The over-temperature protection circuit can automatically stop outputting current when the instrument exceeds the set temperature, ensuring safe use of the instrument.
5. High quality: Key components are all 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 functions: The current can be freely selected among 50A, 100A, 150A, and 200A, and the test time can be arbitrarily set 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 a 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, and further analysis and processing can be performed with host computer software.
9. Easy to use: Small size, light weight, and portable.
