For standardization, how many steps above or below the nameplate rated voltage are transformers manufactured with taps?

Transformers are commonly designed with taps to allow for voltage adjustments to accommodate variations in supply voltage and load conditions. This ensures that the transformer can maintain its performance within acceptable limits while working in different environmental or system conditions.

In standard practice, transformers typically include taps that enable adjustments of up to two and a half steps above or below the nameplate rated voltage. Each step generally represents a specific percentage of the rated voltage (often in line with the standard practices set by manufacturers and electrical engineering guidelines). This provision for fine-tuning the voltage output helps to optimize the operation of the connected electrical equipment while ensuring reliability and efficiency in power delivery.

By allowing two and a half steps, manufacturers cater to different operating conditions while still maintaining a manageable number of voltage variations for the user to select from, providing flexibility in installation without complicating the design excessively. This is why the correct answer indicates two and a half steps as the standard for transformers with taps.