Loop Resistance Tester Commonly Known as Contact Resistance Tester
Source: Yangzhou Darui Electric Co., Ltd.
Date: 2026-02-26
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Company News
High-current constant source injection: outputs DC 100A / 200A / 400A / 600A or even higher DC current. The high current can break through oxidation films, simulating actual equipment operating conditions to measure true contact resistance. Four-terminal method: two current leads (C1, C2) inject current, two voltage leads (P1, P2) capture the voltage drop. Since the voltage input impedance is extremely high, the measurement circuit draws virtually no current, effectively eliminating the influence of lead resistance and contact resistance, ensuring high-precision micro-ohm measurements.
Loop Resistance Tester Commonly Known as Contact Resistance Tester
or “micro-ohmmeter,” is a precision instrument in power systems specifically designed to measure the contact resistance of conductive circuits such as high-voltage circuit breakers, disconnect switches, busbar connections, and cable joints. Its core task is to detect minute resistance increments (micro-ohm level) caused by poor contact, oxidation, looseness, or erosion. These tiny resistances generate enormous heat when high current passes through (P=I²R), which can lead to contact welding or insulation burnout in severe cases. Therefore, accurate loop resistance measurement is critical to ensuring the safe operation of power systems.
