1. INTRODUCTION
COMPONENT RATINGS FOR PROPER VOLTAGE REGULATION
When retrofitting or installing a system containing an automatic voltage regulator to correct system voltage sags and swells, it is critical to coordinate breaker, step-down-transformer and voltage regulator ratings. This process, while straightforward, is often complicated by commercial considerations, such as the ratings of existing equipment or the magnitude of sags and swells.
In this discussion, we examine voltage and current requirements of system components – from input breaker to step-down transformer to voltage regulator – when supplying a typical system. A load provided with constant power (kW or kVA) in a situation with variable source voltage must allow the current drawn from the source to vary inversely to the change in voltage to supply the required power (S=V x I).