🔍 Key Concepts

• Transformer turns ratio between a 480 VAC primary and 120 VAC secondary • How shorted turns vs open windings affect secondary voltage and current • Difference between a complete open circuit (primary or secondary open) and a partially shorted winding

💭 Think About

• First, calculate the normal turns ratio for a 480/120 transformer and what secondary voltage you should read with 480 VAC applied and no fault present. • Then, for each fault choice, ask: would this give me zero volts, normal volts, or reduced/increased volts on the secondary? • Think about what happens to the effective number of turns on each winding if some turns are shorted together vs if the winding is open.

✅ Before You Answer

• Verify what the expected secondary voltage is for a healthy 480/120 transformer. • For an open primary or open secondary, verify whether any voltage can be induced or measured across X1–X2. • For shorted turns, verify whether the effective turns on that winding go up or down, and how that changes the X1–X2 voltage with 480 VAC on H1–H2.