Question

Voltage egulation of large transformer is mainly influenced by

Answer 1

Explanation:

In any step down transformer, the secondary current produces voltage drop across the resistive and reactive components of the transformer's secondary side. On the other side, the primary current produces voltage drops across the resistive and reactive components of the transformer's primary side. From this, it's easy to see the primary voltage will be less than the supply voltage, and the secondary (output) will be less than either of those.

Let's assume you have no load connected to your transformer. In such a case, no secondary current flows. With no current, you have no voltage drop across those resistive and reactive components of the transformer's secondary side. But, another thing happens. Without a secondary current, the primary current drops to the no-load current—which is nearly zero. This means the voltage drop across the resistive and reactive components of the transformer's primary side becomes very small. What's the net effect? In a no-load situation, the voltage on the primary is almost equal to the supply voltage, and the secondary voltage nearly equals the supply voltage times the ratio of primary windings to secondary windings.