Which statement describes not being one of the three main transformer components?

• A. Lightning Arrestor
• B. Core
• C. Windings
• D. Insulating Fluid

Answer: (A)

The thing being tested is which items are the three essential parts that make up the transformer’s energy-transfer structure. A transformer relies on a magnetic core to provide a low-reluctance path for magnetic flux, windings (primary and secondary) to carry the voltages and interact magnetically, and insulating fluid to keep those parts electrically insulated and cooled. The lightning arrestor, on the other hand, is a protective device mounted with the transformer to shunt dangerous voltage surges to ground. It isn’t part of the energy-transfer path or the core electrical structure, so it isn’t considered one of the main transformer components. That’s why the lightning arrestor is the correct choice when identifying something that is not among the core components.