DC Resistance Tester is often abbreviated as Direct Resistance Meter in the power industry
When measuring extremely low resistance, it is also called a "micro-ohmmeter".
If the transformer ratio mentioned earlier is to check the transformer's "gear shifting capability", then the DC resistance tester is to perform a precise "vascular patency check" on the internal windings and conductive circuits of the transformer. Its core task is to measure extremely low DC resistance with high precision, thereby detecting hidden connection issues in the internal conductive circuits of the equipment.
⚙️ Core Uses and Importance
The measurement of DC resistance is an essential test item for inductive loads such as transformers, instrument transformers, and large motors after factory testing, handover, major overhauls, and changes to tap changers.
Core Function: By measuring the DC resistance of the windings, it can accurately check whether the welding or connection quality of the leads is good, whether there are inter-turn short circuits or open circuits inside the windings, whether the tap changer contacts are properly engaged, and whether there are manufacturing defects or operational hazards such as broken strands in multi-strand parallel windings.
Wide Application: In addition to transformers, it is also widely used to measure the contact resistance of high-voltage switches (circuit breakers), the DC resistance of cable conductors, and the loop resistance of busbar connection points. It is a mandatory test item in preventive tests for power systems.
