The ABB 9T51B0129 Buck-Boost Transformer is a versatile and efficient solution for adjusting supply voltage levels. With a capacity of 0.75Kva, this single-phase, dry-type distribution transformer is designed with dual voltage primary and secondary capabilities, allowing for a wide range of voltage combinations. Ideal for applications requiring minor voltage adjustments, it can effectively buck (lower) or boost (raise) the supply voltage by 5 to 27%. Housed in a NEMA 3R nonventilated weatherproof enclosure, it is suitable for both indoor and outdoor use. The transformer features an encapsulated copper core and coils, along with an integrated junction box that includes a ground lug for straightforward wiring. This design is particularly beneficial when connecting three units to form a 3-phase autotransformer. The improved termination spacing and ample wiring compartment provide flexibility in choosing UL listed connectors for copper or aluminum cables. Compliant with NEC Article 210-9, Exception 1, when field connected as an autotransformer, the ABB 9T51B0129 is also RoHS compliant, UL and cUL Listed, and meets the seismic requirements of IEEE-693-2005, IBC-2021, and CBC 2022, ensuring reliability and safety in various environments.