Unit 2 Science Flashcards
Q: When is a neutral used in a three-phase system?
Q: What does the neutral do in an unbalanced system?
Q: Where is this configuration commonly used?
A: A neutral is included when:
Single-phase loads require power.
Unbalanced loads need a return path for the imbalance.
A: It carries the difference between the phase currents.
A: In mixed systems like buildings with both three-phase and single-phase equipment.
Q: Why use the 3-Wire Supply 400v?
Q: Why use the 400V Supply?
A: For balanced loads like motors and pumps.
A: For systems with both three-phase and single-phase devices, like lighting and appliances.
Q: What is a common use for a Three-Phase 3-Wire supply?
A: Balanced three-phase loads like industrial motors.
Q: What is a common use for a Three-Phase 400V supply?
A: Mixed loads in buildings, such as lighting, appliances, and motors.
Q: How are windings connected in a Delta configuration?
A: End-to-end in a closed loop, forming a triangle shape.
Q: What are the key features of Delta configuration?
No neutral wire.
Phase-to-phase voltage = winding voltage.
Handles high currents effectively.
Q: What are the key features of Star configuration?
Neutral wire present.
Phase-to-neutral voltage < phase-to-phase voltage (e.g., 230V vs. 400V in the UK).
Allows single-phase and three-phase loads
Q: Where is Star configuration commonly used?
A: In buildings with mixed single-phase and three-phase loads, such as homes and schools.
Q: What is the key difference between Delta and Star configuration regarding neutral?
Delta: No neutral wire.
Star: Neutral wire is present
Q: What analogy explains Delta vs. Star configurations?
Delta: A triangle racetrack where electricity flows continuously in a loop.
Star: A wheel with spokes where electricity can go to the hub (neutral) or along the spokes (phases
Q: Where is Delta configuration used in real life?
A: In large factories for powering heavy-duty motors and conveyor belts.
Q: Where is Star configuration used in real life?
A: In homes, schools, and offices for appliances requiring lower voltage, like lights and TVs.
Q: What is the Star (Y) configuration used for in three-phase systems?
A: It is used in three-phase four-wire systems, providing:
400V phase-to-phase for three-phase equipment.
230V phase-to-neutral for single-phase loads like lights and outlets.
A neutral wire for unbalanced loads and single-phase devices.
Q: What is the Delta (Δ) configuration used for in three-phase systems?
A: It is used in three-phase three-wire systems, providing:
400V phase-to-phase voltage only (no neutral).
Suitable for balanced loads like motors and pumps.
