Currently, in the measurement of contact resistance in power systems, the conventional QJ44 double-arm DC bridge is commonly used, but the test current of such bridges is only in the mA level, making it difficult to detect defects caused by 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. Therefore, the Ministry of Electric Power standard SD301—88 "AC 500KV Power Equipment Handover and Preventive Test Procedures" and the new edition of "Preventive Test Procedures for Power Equipment" stipulate that the measurement current for contact resistance of circuit breakers and disconnectors should not be less than DC 100A to ensure accurate test results.
The HLY-200A Loop Resistance Tester is designed based on the latest power execution standard DL/T845.4-2004 of the People's Republic of China, combining high-frequency switching power supply technology with digital circuit technology. It is suitable for measuring the loop resistance of switch control equipment. The test current adopts DC 100A and 200A recommended by national standards. It can directly measure loop resistance at a current of 100A, and also directly measure loop resistance at a current of 200A, with the final test results displayed digitally.The instrument has accurate measurement, stable performance, and meets the requirements of on-site high-voltage switch maintenance in power and power supply departments, as well as loop resistance testing in high-voltage switch factories.
Performance Features
1. High Current: Using the latest power supply technology, it can continuously output high current for a long time, overcoming the drawbacks of instantaneous current in pulse power supplies, effectively breaking through the oxide film on switch contacts, and obtaining good test results.
2. Strong Anti-interference Capability: Under severe interference conditions, the last digit of the LCD screen can stabilize within ±1 digit, with stable readings and good repeatability.
3. Long Service Life: All high-precision resistors are used, effectively eliminating the influence of ambient temperature on measurement results, and enhancing vibration resistance.
4. Easy to Carry: Small size, light weight.
Technical Specifications
1. Measurement Range: 1～1999μΩ.
2. Resolution: 1μΩ.
3. Test Current: DC 50A, 100A, 150A, 200A four fixed outputs.
4. Measurement Accuracy: 0.5%±1d.
5. Working Mode: Continuous.
6. Display Mode: Three and a half digit LCD.
7. Power Supply: AC220V±10% , 50Hz.
8. Working Environment: Temperature -10℃～40℃, Humidity ≤80 %RH.
9. Dimensions: 380mm×350mm×260mm.
10. Weight: 5kg (excluding accessories).
