Final answer:
The correct number of loops for an ideal step-down transformer with a voltage ratio of 2400/120V, but operating at a grid voltage of 2.6 kV, is 500 primary loops and 25 secondary loops, reflecting a 20:1 turns ratio in accordance with the ratio of primary to secondary voltage.
Step-by-step explanation:
To determine the number of loops (or turns) in the primary and secondary windings of a step-down transformer, we use the transformer's voltage ratio and the formula relating the primary and secondary voltages to the number of turns in their respective windings: Vp/Vs = Np/Ns (where Vp and Vs are the primary and secondary voltages, and Np and Ns are the number of primary and secondary turns, respectively).
Given the ideal transformer has a rated voltage ratio of 2400/120V, but it is connected to a grid voltage of 2.6 kV (or 2600V), we adjust the voltage ratio according to the actual primary voltage. We do this by keeping the turns ratio (Np/Ns) constant while calculating Np and Ns with the actual voltage.
The actual turns ratio, based on the grid connection, would be 2600V/120V. Using the given standard ratio of 2400/120V and simplifying, we get a turns ratio of 20:1, which means that for every 20 turns on the primary, there is 1 turn on the secondary.
Option A (Primary: 500 loops, Secondary: 25 loops) reflects a turns ratio of 20:1. Since the other options (B, C, and D) do not reflect this ratio, they can be eliminated. Therefore, the calculation for the desired number of turns would be:
- Primary: 500 loops
- Secondary: 25 loops