Product Overview
Currently, the conventional QJ44 double-arm DC bridge is widely used in power systems for measuring contact resistance. However, the test current of this bridge is only at the milliampere level, making it difficult to detect defects such as reduced cross-sectional area of circuit conductors. When measuring the contact resistance of high-voltage switchgear conductive circuits, due to the influence of oil films and oxide layers between contacts, the measured value may be several times larger, failing to accurately reflect the true contact resistance. To address this, 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 shall not be less than 100A DC, ensuring accurate test results. This product is designed based on the latest Chinese electric power execution standard DL/T845.4-2004, combining high-frequency switching power supply technology with digital circuit technology. It is suitable for measuring the circuit resistance of switch control equipment. The test current adopts the national standard recommended DC 100A and 200A. It can directly measure the circuit resistance at a current of 100A, and also at 200A, with the final test results displayed digitally. This instrument provides accurate measurement and stable performance, meeting the requirements for on-site high-voltage switch maintenance by power and supply departments, as well as circuit resistance testing in high-voltage switch factories.
