The delta connection is one of the common methods of connecting the windings (coils) of a three-phase alternator or generator. In a delta-connected alternator, the windings are arranged in the shape of a delta or triangle when drawn schematically. The delta connection offers certain advantages and is widely used in various three-phase electrical systems. Here's how it works:

In a delta-connected alternator:

1. Three Windings: There are three sets of windings, typically labeled as A, B, and C. These windings are evenly spaced around the alternator's stator.

2. Phases: The three windings are directly connected to the three phases of the alternator's output. These phases are usually labeled as L1, L2, and L3.

3. Line-to-Line Voltage: The voltage between any two phases (e.g., L1 to L2, L2 to L3, or L3 to L1) is referred to as the line-to-line voltage (Vll). This voltage is typically used for three-phase loads.

4. No Neutral Point: Unlike the wye (star) connection, the delta connection does not provide a neutral point. As a result, there is no direct connection to ground, and the voltage is balanced between the three phases.

Advantages of the delta connection:

1. Higher Line-to-Line Voltage: The line-to-line voltage (Vll) in a delta-connected system is the same as the phase voltage (Vph), making it suitable for high-voltage applications.

2. Simplicity: Delta-connected systems are often simpler in design because they do not require a neutral point or grounding.

3. Balanced Voltage: In a balanced load, the voltages across each phase are equal in magnitude and 120 degrees apart in phase, making it suitable for powering three-phase motors and other equipment.

4. No Neutral Current: In a delta-connected system with a balanced load, no current flows in the neutral conductor (if present). This can reduce the size of conductors and equipment.

Delta-connected alternators are commonly used in industrial and commercial applications, especially when high power and voltage levels are required. They are well-suited for supplying power to three-phase motors, transformers, and other equipment that operates on three-phase power.

It's important to note that the choice between delta and wye (star) connections depends on the specific application and electrical requirements. Each connection has its advantages and is chosen based on the voltage and current characteristics needed for the loads being powered.