Transformer (distribution)
Beginner
A big device that lowers the strong push of electricity from power lines to a level the building can use.
Novice
An electrical machine that changes AC voltage with almost no loss, for example from tens of thousands of volts to 480 volts. Datacenter transformers are typically more than 99% efficient.
Expert
Losses split into no-load (core) loss, paid even at zero load, and load (copper) loss that grows with current squared, so efficiency peaks at partial load. U.S. minimum efficiencies in 10 CFR 431.196 are set at 50% load for liquid-immersed and medium-voltage dry-type units and at 35% for low-voltage dry-type units. Lead times for large units have become a constraint on new sites.