200V to 220V Buck-Boost Transformer — Step-up, 3-Phase Delta
See how a 200V to 220V 3-phase delta buck-boost transformer corrects voltage and how to select the proper model.
Choosing a 200V to 220V transformer
A 200V to 220V buck-boost transformer raises a 200 volt supply by 10 percent so equipment built to a 220 volt nameplate sees what it was designed for. Two situations produce this pair. The first is an older industrial building still distributing a legacy 200 volt system. The second is a machine specified at 220V landing on a 208V service that measures closer to 200 under load. Both single-phase and three-phase corrections are offered, in load ratings of 10, 15, 20, 30, 40, 50 and 60 amps.
The 200 volt to 220 volt correction shows up in buildings and equipment that predate the 208Y/120 standard, and in imported machinery specified for a 200 volt domestic supply but built around 220 volt components. Older plants still distribute 200 volts to machine tools, and the control transformers, brake coils and resistance heaters inside those machines were frequently ordered for 220.Typical loads on this correction:Machine tools with 220V spindle motors, coolant pumps and brake solenoidsImported molding auxiliaries, chillers and dryers marked 220VOlder welders and resistance heating equipment carrying a 220V input ratingCommercial laundry extractors and dryers on legacy 200 volt panelsPackaging and conveyor drives with 220V contactor coilsFarm and fleet shop equipment fed from a long 200 volt serviceThe common thread is that the equipment is not adjustable. There is no tap to move, no dual-voltage jumper on the terminal block, and replacing internal components costs more than correcting the supply that feeds them.