What is typically necessary to install if a power transformer lacks auto tap changing underload equipment?

When a power transformer does not have auto tap changing underload equipment, it is essential to install voltage regulators. Voltage regulators are devices that maintain a constant voltage level. They adjust the output voltage to compensate for variations in load or input voltage, ensuring that the voltage supplied to the electrical system remains stable. This is crucial for protecting sensitive electrical equipment and maintaining the quality of power supplied.

In the absence of automatic tap changing, which would allow for real-time adjustments to the transformer’s output voltage based on load conditions, voltage regulators serve this critical function. They help to accommodate fluctuations in demand and can effectively manage voltage levels without requiring manual intervention or additional hardware.

The other options, such as backup generators, transformers, and capacitors, serve different purposes. Backup generators are primarily for providing emergency power, transformers are used for voltage level changes rather than regulation, and capacitors are typically involved in power factor correction and voltage stabilization rather than direct voltage regulation under varying loads.