In a three-phase system, a Y-connected (wye) source feeds a Δ-connected (delta) load. For each delta phase element, what voltage appears across it relative to the source line voltage?

Introduction / Context:Delta–wye interconnections are common in power systems and laboratory setups. This question checks your understanding of how line and phase voltages map across a Δ-connected load when the source is Y-connected. Getting this right is essential for rating load components and predicting current and power in three-phase networks.

Given Data / Assumptions:

• Balanced, sinusoidal three-phase system.
• Source side is Y (wye) connected; load side is Δ (delta) connected.
• We compare the voltage across each delta phase element to the source line voltage.

Concept / Approach:In a Y source, the line-to-line voltage V_LL equals √3 times the phase (line-to-neutral) voltage. A delta load connects each phase element directly between two lines, so each delta branch sees the line-to-line voltage. Therefore, the voltage across each delta phase equals the source V_LL, not a fraction of it.

Step-by-Step Solution:

Verification / Alternative check:Measure with a meter: place probes across any one delta element; the reading is the same as the source line-to-line voltage because those two terminals are the same line conductors feeding the element.

Why Other Options Are Wrong:

• One-third / two-thirds: There is no 1/3 or 2/3 factor in Δ branch voltage relative to V_LL.
• Difference involving neutral voltage: The delta element is not connected to neutral; it is strictly line-to-line.

Common Pitfalls:

• Confusing Y relations (V_LL = √3 V_phase) with Δ branch conditions (branch = V_LL).
• Thinking a neutral affects the delta branch voltage—delta branches do not reference neutral.

Final Answer:each phase of the load has the full line voltage across it