208V to 222V Buck-Boost Transformer — Step-up, Single Phase
See how a 208V to 222V single phase buck-boost transformer corrects voltage and how to select the proper model.
Choosing a 208V to 222V transformer
Equipment nameplated 220V turns up constantly on imported machinery, older US-built gear and packaged systems designed around a 220 to 230 volt band. On a 208V service that equipment runs about 5.5 percent low, which looks acceptable on paper but leaves nothing in reserve when the building sags under afternoon load. A 208V to 222V buck-boost transformer applies a deliberately modest 6.7 percent boost, landing just above 220V without pushing 220V-rated coils, timers and power supplies toward their upper limits. Both phase configurations are offered, and the selection is made by circuit amperage.
The 220V nameplate is a legacy of both older American practice and of equipment designed for markets where 220V and 230V are the standard. It arrives in US buildings by import, by purchase of used machinery, and by specification of packaged systems engineered somewhere else.Commercial laundry: washer-extractors, tumble dryers and flatwork ironers in hotels, care facilities and route laundries.Imported woodworking, CNC, plastics and packaging machinery whose control transformers and starters are configured for 220V.Laboratory and medical equipment including autoclaves, centrifuges, incubators and sterilizers.Bakery and food processing equipment: proofers, dough sheeters, slicers and small deck ovens.Older shop machinery kept in service long past the era when 220V was the common way to describe a two-pole circuit.The recurring situation is a machine that arrives with a European or Asian data plate, gets connected to whatever the shop has available, and then throws intermittent faults that the supplier blames on the installation while the installer blames the machine. A meter at the disconnect usually settles it.