The voltage across the transformer primary during operation is:

The voltage across the transformer primary during operation is:

• A. 24 V
• B. 120 V
• C. 240 V
• D. 480 V

Answer: (C)

The voltage across the transformer primary is the voltage that the electrical supply provides to the winding. In operation, the primary voltage equals the line voltage feeding the transformer. For this unit, the primary is designed to be connected to 240 V, so it experiences about 240 V during normal operation. The other voltages listed (24 V, 120 V, 480 V) are not the rated primary for this transformer, though they and other values appear in different systems or configurations. The secondary voltage will be set by the turns ratio, but the primary voltage remains the line voltage it’s connected to, typically around its rated value with only small drops due to impedance.

The voltage across the transformer primary is the voltage that the electrical supply provides to the winding. In operation, the primary voltage equals the line voltage feeding the transformer. For this unit, the primary is designed to be connected to 240 V, so it experiences about 240 V during normal operation. The other voltages listed (24 V, 120 V, 480 V) are not the rated primary for this transformer, though they and other values appear in different systems or configurations. The secondary voltage will be set by the turns ratio, but the primary voltage remains the line voltage it’s connected to, typically around its rated value with only small drops due to impedance.