208V to 229V Buck-Boost Transformer — Step-up, Single Phase
See how a 208V to 229V single phase buck-boost transformer corrects voltage and how to select the proper model.
Choosing a 208V to 229V transformer
A 230V motor on a 208V service runs about 10 percent below nameplate, right at the edge of what NEMA MG-1 allows and past the point where the machine behaves the way its designer intended. A 208V to 229V buck-boost transformer closes that gap, lifting the supply about 10 percent so 230V equipment sees essentially nominal voltage. This is the correction to reach for when the nameplate reads 230V rather than 240V, which covers most North American motors, pumps and compressors. The correction is offered in both single-phase and three-phase form, selected by the current the circuit carries.
This correction belongs to rotating equipment. Almost every general-purpose induction motor sold in North America carries a 230V or 208-230V nameplate, and the ones marked 230V alone are the ones that struggle on a 208Y/120 building service.Air compressors and vacuum pumps in shops, dental and medical suites, and light manufacturing.Booster, sump, transfer and circulating pumps in mechanical rooms and pump houses.Air handlers, fan coils, exhaust fans and cooling tower fans across commercial HVAC systems.Conveyors, mixers, grinders, saws and other machine tools, including imported equipment configured for a 230V supply.Elevator and dumbwaiter machine room equipment in older mid-rise buildings.The complaint is rarely that the motor will not start. It is that a motor runs hot to the touch, an overload relay trips on humid afternoons, a compressor takes longer than it used to in order to build pressure, or a set of identical motors fails years earlier than the ones in a sister building across town that happens to sit on a 240V service.