Currently, in the measurement of contact resistance in power systems, the conventional QJ44 double-arm DC bridge is commonly used. However, 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. Therefore, the Ministry of Electric Power standard SD301—88 "Procedures for Handover and Preventive Tests of AC 500KV Power Equipment" and the new edition of "Procedures for Preventive Tests of 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 Chinese electric power executive standard DL/T845.4-2004, combining high-frequency switching power supply technology and digital circuit technology. It is suitable for measuring the loop resistance of switch control equipment. Its test current adopts DC 100A and 200A recommended by national standards. The loop resistance can be directly measured at a current of 100A, and also at a current of 200A, with the final test results displayed digitally.The instrument features accurate measurement, stable performance, and meets the requirements of on-site high-voltage switch maintenance and loop resistance testing in power supply departments and high-voltage switch factories.
Performance Features
1. High Current: Utilizing 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 can remain stable 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, while the use of military-grade connectors enhances vibration resistance.
4. Easy to Carry: Compact 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).
