Noun
autotransformer (plural autotransformers)
(electrical engineering) A transformer with a single winding, its output being taken from taps.
At that time, capacitors were more expensive than transformers, so an autotransformer was used to apply more power through fewer capacitors. Source: Internet
Depending on the design, changing the autotransformer tap can cause a very brief output power disruption, citation which may cause UPSs equipped with a power-loss alarm to "chirp" for a moment. Source: Internet
It instead compensates by automatically selecting different power taps on the autotransformer. Source: Internet