A transformer is an electrical device that uses electromagnetic induction to transfer electrical energy from one circuit to another. The transformer can increase or decrease the voltage without changing the frequency. Transformers are used for a variety of purposes, including power transmission and signal isolation.
Transformers can be single-phase or three-phase. Single-phase transformers have one primary winding and one secondary winding. Three-phase transformers have three sets of windings.
Transformer capacity is rated in kilovolt-amps (KVA). The formula for calculating KVA is volts x amps / 1000.