In a three-phase delta system, if the line current is known, how do you find the phase current?

In a three-phase delta system, the relationship between line current and phase current is defined by the configuration of the system. In a delta connection, each phase is connected in a loop, with two phases connecting at each corner.

To find the phase current from the line current in a delta system, you divide the line current by √3. This is because the line current is the current flowing through each of the three lines supplying the system, while the phase current is the current flowing through each phase winding of the delta network.

In a delta connection, the line current will carry the summation of the phase currents but is proportioned differently due to the geometrical relationship of the currents. Specifically, the phase currents are, in effect, a fraction of the line currents, governed by the √3 factor which arises from the phase shift in a three-phase system. Thus, the correct approach for conversion from line current to phase current involves dividing the line current by √3.

This principle is essential in understanding load calculations, circuit design, and efficiency in three-phase power systems, especially for engineers and technicians working in electrical installations.