In the current power system, the conventional QJ44 type double-arm DC bridge is commonly used to measure the DC resistance of transformer coils and the contact resistance of high-voltage circuit breakers. However, the test current of such bridges is only at the mA level, making it difficult to detect defects such as reduced cross-sectional area of conductors in transformer coil conductive loops. When measuring the contact resistance of high-voltage switch conductive loops, due to the influence of oil films and oxide layers between moving and static contacts, the measurement deviation is large, masking the true contact resistance value. Therefore, the Ministry of Electric Power standard SD301-88 "AC 500KV Electrical Equipment Handover and Preventive Test Procedures" and the new edition of "Preventive Test Procedures for Electrical Equipment" stipulate that the measurement current for contact resistance of circuit breakers and disconnectors shall not be less than DC 100A to ensure accuracy.
Product aliases of HLY-II Loop Resistance Tester
Contact resistance tester, switch loop resistance tester, contact loop resistance tester, contact (loop) resistance tester, micro-ohmmeter
Product features of HLY-II Loop Resistance Tester
The loop resistance tester adopts a micro single-chip microcomputer control and a user-friendly Chinese character interface display. It is a dedicated device for measuring contact resistance and loop resistance of switch control equipment; its test current adopts the 100A/200A DC recommended by the national standard GB763. It can directly measure loop resistance or contact resistance under a current of 100A/200A (test selection gear), with pioneering test time setting and pioneering automatic identification of open circuit in high test current!!! It uses a liquid crystal display to show the test current value and test resistance value, can print output, or upload to a computer via RS232 interface for storage. This instrument has accurate measurement, stable performance, and convenient operation. It is suitable for on-site high-voltage switch maintenance in power and power supply departments and loop resistance measurement in high-voltage switch factories.
