Attributes . Encapsulated core and coil; Buck-boost transformers are small single phase transformers designed to reduce (buck) or raise (boost) line voltage from 5 - 20 PCT; The most common example is boosting 208 - 230 V, usually to operate a 230 V motor such as an air-conditioner compressor, from a 208 V supply line; Buck-boost transformers are an economical way to correct a potentially very serious problem; Anytime a line voltage change in the 5 - 20 PCT range is required, a buck-boost transformer should be considered as your first line of defense; 10-year limited warranty . Names