# star connection

> 3-phase circuit

**Wikidata**: [Q2345935](https://www.wikidata.org/wiki/Q2345935)  
**Source**: https://4ort.xyz/entity/star-connection

## Summary
Star connection is a 3-phase circuit configuration used in electrical systems. It is also known as Y connection or wye connection, and is classified as an electronic component that affects electrons or their associated fields.

## Key Facts
- Instance of: electronic component
- Aliases: Y connection, wye connection, connexion en étoile
- IEV number: 141-02-06
- Different from: delta connection
- Wikimedia sitelink count: 3
- Commons category: Wye connection
- Wikipedia languages: commons, de, pl
- Google Knowledge Graph ID: /g/121x_v8n
- GND ID: 4790321-1
- Image available: https://commons.wikimedia.org/wiki/Special:FilePath/AC_star_connection.svg

## FAQs
### Q: What is a star connection in electrical systems?
A: A star connection is a 3-phase circuit configuration where three components are connected to a common neutral point, forming a Y shape. It is used in electrical power distribution and motor control systems.

### Q: How does star connection differ from delta connection?
A: Star connection differs from delta connection in its topology - star has a common neutral point while delta forms a closed loop. Star connections typically have lower voltage across each component compared to delta connections.

### Q: What are the main applications of star connection?
A: Star connections are primarily used in three-phase power distribution systems, motor starters, and transformer windings. They are particularly useful in systems where a neutral point is needed for grounding or where lower phase voltages are desired.

## Why It Matters
Star connection is a fundamental configuration in three-phase electrical systems that enables efficient power distribution and motor control. Its Y-shaped topology provides a neutral point that can be grounded, improving system safety and allowing for both three-phase and single-phase power delivery from the same system. This versatility makes star connections essential in industrial power distribution, where they can supply different voltage levels to various equipment. The configuration also reduces the voltage stress on individual components compared to delta connections, making it suitable for high-voltage applications. In motor control, star connections are used in star-delta starters to reduce starting current, protecting equipment and reducing mechanical stress. The widespread adoption of star connections in power systems worldwide has standardized three-phase power delivery, enabling the global compatibility of electrical equipment and facilitating international trade and power system interconnections.

## Notable For
- Standard configuration in three-phase power distribution systems
- Provides neutral point for grounding and fault protection
- Enables both three-phase and single-phase power delivery
- Used in star-delta motor starters for reduced starting current
- Lower voltage stress on components compared to delta connections

## Body
### Technical Characteristics
Star connection is characterized by its Y-shaped topology where three components (such as windings or impedances) are connected to a common neutral point. This configuration results in a line-to-line voltage that is √3 times the line-to-neutral voltage. The neutral point can be grounded, providing a reference for the system and improving safety by limiting voltage surges.

### Comparison with Delta Connection
Unlike delta connections which form a closed loop, star connections have an open center where the neutral point is located. This fundamental difference affects their applications and performance characteristics. In a star connection, the phase current equals the line current, while in a delta connection, the line current is √3 times the phase current.

### Applications in Power Systems
Star connections are extensively used in power distribution transformers, where they allow for the delivery of both three-phase power to industrial loads and single-phase power to residential and commercial users. The neutral point in star-connected systems can be grounded, providing a stable reference voltage and enabling protective devices to operate effectively during ground faults.

### Motor Starting Applications
In motor control, star connections are used in star-delta starters to reduce the starting current of induction motors. During startup, the motor is connected in star configuration, reducing the voltage across each winding to 1/√3 of the line voltage. After acceleration, the connection switches to delta for normal operation. This method reduces the starting current to about one-third of what it would be with direct-on-line starting, minimizing voltage dips in the power supply system.

### Standards and Classifications
Star connections are classified under the International Electrotechnical Vocabulary (IEV) with the number 141-02-06. They are recognized as a specific type of electronic component that affects electrons or their associated fields. The configuration is documented in various international standards for electrical systems and is a fundamental concept taught in electrical engineering curricula worldwide.