Question

Which transformer is known as a single winding transformer?

• A. Auto transformer
• B. Voltage transformer
• C. Potential transformer
• D. Current transformer

Hint:

While auto transformers are highly efficient and cost-effective for small voltage adjustment ratios, they lack electrical isolation between the primary and secondary sides, which can introduce safety concerns in some applications.

Answer 1

The Correct Option is A

Step 1: Comparing Transformer Windings:
Standard isolation, potential, or current transformers utilize two electrically separate windings: a primary winding and a secondary winding. Power is transferred between them purely via magnetic induction through a magnetic core.

Step 2: Analyzing the Auto Transformer:
An Auto transformer utilizes a single continuous winding wound on an iron core. This single winding serves as both the primary and secondary winding.

• A portion of this single winding is shared by both the input (primary) and output (secondary) circuits.
• Electrical power is transferred through both electromagnetic induction and direct electrical conduction, which makes the transformer smaller, lighter, and more efficient than standard two-winding models.

Step 3: Conclusion:
Therefore, the Auto transformer is known as a single winding transformer, corresponding to option (A).