Product Overview
At present, the conventional QJ44 double-arm DC bridge is commonly used in power systems for measuring contact resistance. However, the test current of this bridge is only at the mA level, making it difficult to detect defects such as reduced cross-sectional area of the circuit conductor. When measuring the contact resistance of the conductive circuit in high-voltage switches, 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 Ministry of Electric Power standard SD301—88 "Regulations for Handover and Preventive Tests of AC 500KV Electric Power Equipment" and the new edition of "Regulations for Preventive Tests of Electric Power Equipment" stipulate that the measurement current for contact resistance of circuit breakers and disconnectors shall not be less than DC 100A, to ensure 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 DC 100A and 200A recommended by national standards. It can directly measure the circuit resistance at a current of 100A, or at a current of 200A, and the final test results are displayed digitally. This instrument provides accurate measurement and stable performance, meeting the requirements for on-site high-voltage switch maintenance in power and supply departments, as well as circuit resistance testing in high-voltage switch factories.
