In a Delta connection, the line voltage is equal to the phase voltage.
### Explanation:
To understand why this is the case, let's first define what we mean by "line voltage" and "phase voltage."
- **Line Voltage (V<sub>L</sub>)**: This is the voltage measured between any two of the three lines (or wires) in a three-phase system. For example, in a three-phase system with three lines A, B, and C, the line voltage is measured between A and B, B and C, or A and C.
- **Phase Voltage (V<sub>ph</sub>)**: This is the voltage measured across a single winding or phase of a three-phase machine (e.g., a motor or transformer) in a three-phase system.
### Delta Connection:
In a Delta (Δ) connection, each phase of a three-phase system is connected end-to-end in a closed loop, forming a triangular (Δ) shape. Here's how it works:
- Each corner of the delta represents a phase winding.
- The line voltage is the voltage between any two corners (phases) of the delta.
Because of this configuration:
1. **Line Voltage and Phase Voltage Relationship**:
- In a Delta connection, each line is directly connected to two phases. As a result, the line voltage (V<sub>L</sub>) is directly across the phase windings.
- Therefore, the **line voltage (V<sub>L</sub>) is equal to the phase voltage (V<sub>ph</sub>)** in a Delta connection. Mathematically:
\[
V_L = V_{ph}
\]
### Comparison with Star (Y) Connection:
For comparison, in a Star (Y) connection, the line voltage is not equal to the phase voltage. Instead, it is:
\[
V_L = \sqrt{3} \times V_{ph}
\]
This is because, in a Star connection, the line voltage is the vector sum of the voltages of two phases, whereas, in a Delta connection, the line voltage is directly across the phase windings.
### Conclusion:
In summary, in a Delta (Δ) connection, the line voltage (V<sub>L</sub>) is equal to the phase voltage (V<sub>ph</sub>). This characteristic is one of the key differences between Delta and Star (Y) connections in three-phase electrical systems.