Product nicknames: contact resistance tester, switch loop resistance tester, contact loop resistance tester, resistance loop tester, intelligent loop resistance tester, contact resistance tester, contact (loop) resistance tester.

In the past, the conventional QJ44 double-arm DC bridge was generally used in the power system to measure the DC resistance of the transformer coil and the contact resistance of the high-voltage circuit breaker. The test current of this type of bridge is only mA level, and it is difficult to find the conductive loop conductor of the transformer coil Defects of reduced area. When measuring the contact resistance of the conductive circuit of a high-voltage switch, due to the influence of the oil film and the oxide layer between the moving and static contacts, the measurement deviation is large, which conceals the true contact resistance.

Therefore, the Ministry of Electric Power standard SD301-88 “AC 500KV Electrical Equipment Handover and Preventive Test Regulations” and the new version of the “Electrical Equipment Preventive Test Regulations” stipulate that the measuring current of the contact resistance of circuit breakers and disconnectors shall not be less than DC 100A to ensure Accuracy.