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Winding resistance definition

A transformer winding is a group of turns that form an electrical circuit corresponding to a certain voltage value, and the transformer winding is composed of a coil. When the number of turns of each secondary winding is different, the terminal voltage is also different, so the multi-winding transformer can supply power to several different voltage consumers. The most commonly used in power systems is the three-winding transformer.


The DC resistance is the resistance that the component is connected to with direct current, that is, the inherent static resistance of the component. For example, the coil is connected to direct current and alternating current, and the resistance it exhibits is different. The alternating current, the coil has a reactance in addition to the direct current resistance, which reflects the cooperation of the resistor and the reactance, called impedance.


Transformer DC winding resistance refers to the pure resistance of each winding. The smaller the value, the better. What is measured directly at the ends of the winding with an ohmmeter is the DC resistance of the transformer winding. That is the DC resistance of the transformer. By measuring the DC resistance of the transformer, the degree of insulation of the internal coil of the transformer can be judged.


DC resistance test is mainly for DC resistance test of inductive load, such as measurement of winding DC resistance of transformer. It is a convenient and effective test to investigate the connection condition of winding insulation and current loop. It can reflect the quality of winding welding and the short circuit between windings. , winding broken strand or lead wire break, tap changer and wire contact failure, etc., in fact, it is also an effective means to determine whether the DC resistance of each phase winding is balanced and the voltage switch is correct.


The DC resistance test of the transformer winding is an indispensable test item for the transformer after the handover, overhaul and change of the tap changer. The DC resistance tester is an ideal device for measuring the resistance of the transformer winding and the DC resistance of the high-power inductor device. High-capacity transformer three-phase winding DC resistance and optimized design for rapid measurement tester.


The principle of the transformer winding resistance tester is to apply DC current I to the winding, measure the DC voltage V at both ends of the device under test, and then calculate the resistance of the winding with the ohm theorem R=V/I. KRI series  transformer DC winding resistance tester has the characteristics of stable performance,rapid measurement, small size, convenient use, high measurement accuracy, good data repeatability, automatic power-saving and other characteristics. It is an ideal device for measuring transformer winding resistance and DC winding resistance of high-power inductors.