Single Phase Transformers

Single Phase Transformers

Single-phase transformers accept single-phase AC power and output single-phase AC power, typically at a higher or lower voltage level. Energy is transferred from one circuit to one or more circuits via electromagnetic induction.

Operation

A single-phase transformer is a type of power transformer that utilizes single-phase alternating current, meaning the transformer relies on a voltage cycle that operates in a unified time phase. They are often used to step-down long distance and localized transmission currents into power levels more suitable for residential and light-commercial applications. The ratio of primary (input) windings to secondary (output) windings determines the change in current. Single-phase transformers with a 1:1 ratio can be used to isolate circuits. Single-phase transformers abide by Ohm's law, and outside of minor inherent loss due to heat, do not create or remove power.

Single-phase transformers are more popular than three-phase transformers in non-urban areas, as the cost of a three-phase distribution network is much higher, and the overall electrical demand is lower. The highest voltage available in a single-phase network is regulated by utility infrastructure and industrial regulations. A single-phase transformer is frequently used for power distribution and voltage reduction for residential and commercial applications. When used with appliances, the lower voltage output is often rectified into DC current before powering appliances, such as a computer.

High-voltage systems typically employ three-phase transformers to power apartment buildings, retail centers, factories, offices, and other large-scale structures, as well as electric motors—single-phase power supplies do not produce the rotating magnetic field required to induce rotation. Three-phase power systems are more common in cities, where dense power supply demands require transformers that route hundreds or thousands of kVA.