AExE01 · Chapter 1Basic Electrical & Electronics🏛️ Past Licensure QuestionID: f5422782
What is the correct mathematical relationship between Line voltage and Phase voltage in a three-phase star system?
What is the correct mathematical relationship between Line voltage and Phase voltage in a three-phase star system?
Multiple Choice Options
- A
Line voltage = Phase voltage
- B✓ Correct Option
Line voltage = √3 × Phase voltage (Star)
- C
Line voltage = Phase voltage / √3 (Delta)
- D
Line voltage = 2 x Phase voltage
Detailed Technical Solution & Explanation
In a balanced three-phase star (Wye) electrical system, the potential difference between any two line conductors is the phasor difference of two phase voltages displaced by 120°: . In a delta system, line voltage equals phase voltage ().
Option Analysis:
•
Option A (Line voltage = Phase voltage): True only for delta connections.
•
Option B (Line voltage = √3 × Phase voltage (Star)): Correct. Fundamental relationship for 3-phase star systems.
•
Option C (Line voltage = Phase voltage / √3 (De...): Incorrect.
•
Option D (Line voltage = 2 x Phase voltage): Incorrect.
Reference: Demo2 · Set 1NEC Licensure Syllabus