A three-phase transformer DC-resistance is the measure of the opposition to the flow of direct current through the transformer windings. It is an important factor in determining the efficiency and performance of the transformer.
The DC-resistance of a three-phase transformer is typically measured by passing a low voltage direct current through each winding and measuring the resulting voltage drop. The resistance can then be calculated using Ohm's law.
Knowing the DC-resistance of a three-phase transformer is important for calculating the power losses and efficiency of the transformer. It is also useful for detecting any potential faults or damage in the transformer windings.
The DC-resistance of a three-phase transformer increases as the temperature increases. This is because the resistance of the conductor material increases with temperature, causing a higher voltage drop and lower efficiency in the transformer.
The DC-resistance of a three-phase transformer can be reduced by using larger diameter conductors, increasing the number of turns in the windings, or using materials with lower resistivity. However, these changes may also affect other aspects of the transformer's performance and must be carefully considered.