What is the primary voltage rating of a typical single-phase transformer?

The primary voltage rating of a typical single-phase transformer is often specified as 120/240 volts because this configuration allows for flexible application depending on the electrical needs of a residential or commercial setup. This dual voltage rating means that the transformer can serve a wide range of devices and systems, as it can either provide standard 120-volt power for common household appliances or 240 volts for larger equipment.

In residential areas, the 120/240-volt configuration is particularly advantageous as it accommodates different types of loads—120 volts for common household circuits and 240 volts for high-power appliances like dryers or air conditioning units. This versatility makes the 120/240-volt rating a standard in many transformer designs, enabling them to meet the power distribution requirements of various applications.

While the other options, such as 120 volts, 240 volts, and 480 volts, represent individual phase voltages, they do not provide the same level of versatility and adaptability as the 120/240 volts configuration. Thus, the choice reflecting both voltage ratings captures the primary function of the transformer in typical installations.