Final answer:
To determine the current in the neutral conductor of a distribution transformer with multiple secondary loads, it's necessary to consider the phasor sum of the loads. For split-phase systems, assuming balanced loads on different phases, the neutral current is the difference between the two 120V loads: 17A, which corresponds to option B.
Step-by-step explanation:
The student's question is about calculating the current flowing in the neutral conductor of a distribution transformer with multiple secondary loads. The transformer is connected to 240V loads at 18A, a 120V secondary load 1 at 28A, and a 120V secondary load 2 at 11A. To find the current in the neutral wire, one must consider the phasor sum of the currents from the two 120V loads since they are likely on different phases in a split-phase system typically used in residential applications.
Assuming that the 120V loads are on different phases and that there is no phase difference between the currents, the current in the neutral conductor would be the arithmetical sum of the loads connected to a single phase. Therefore, the current would be Ineutral = Iload1 + Iload2 = 28A + 11A = 39A.
However, this value does not match any of the options given, suggesting that the loads may actually be balanced (on opposite phases), which means the current in the neutral would actually be the difference between the two, which is Ineutral = | Iload1 - Iload2 | = | 28A - 11A | = 17A. Since this is an available option, we would select B. 17 A as the correct option for the current flowing in the neutral conductor.