What is the primary purpose of a no load tap changer?

A no load tap changer is specifically designed to allow for voltage adjustments without requiring the transformer to be under load. This device enables operators to change the tap setting—essentially altering the transformer’s winding ratio—while the transformer is not supplying power to a load, thereby managing voltage levels more effectively.

By adjusting the voltage on the secondary side of the transformer, the no load tap changer ensures that the output voltage remains within the desired range, accommodating changes in line conditions, the varying needs of connected circuits, or fluctuations in the power supply. This capability is crucial for maintaining the stability and reliability of the power distribution system.

The incorrect answers highlight other aspects of transformer operation but do not pertain specifically to the function of a no load tap changer. Reducing load on the transformer, maintaining safety during operation, or increasing transformer efficiency are important considerations in transformer management, but they do not directly define the primary purpose of a no load tap changer, which focuses exclusively on enabling voltage adjustments when the transformer is not energizing a load.