Three-phase electric power

Three-phase electric power (abbreviated 3ϕ) is a common type of <a href="/facts/Alternating_current/qxICS3xa">alternating current</a> (AC) used in <a href="/facts/Electricity_generation/Uo6mQQ1T">electricity generation</a>, <a href="/facts/Electric_power_transmission/I9w3lRmM">transmission</a>, and <a href="/facts/Electric_power_distribution/F5NfTeWP">distribution</a>. It is a type of <a href="/facts/Polyphase_system/t90BUSsT">polyphase system</a> employing three wires (or four including an optional neutral return wire) and is the most common method used by <a href="/facts/Electrical_grid/RkWPqjmG">electrical grids</a> worldwide to transfer power.
Three-phase electrical power was developed in the 1880s by several people. In three-phase power, the voltage on each wire is 120 degrees <a href="/facts/Phase_shift/cpGtuVll">phase shifted</a> relative to each of the other wires. Because it is an AC system, it allows the voltages to be easily stepped up using <a href="/facts/Transformer/EYYfXWrF">transformers</a> to high voltage for transmission and back down for distribution, giving high efficiency.
A three-wire three-phase circuit is usually more economical than an equivalent two-wire <a href="/facts/Single-phase_electric_power/fVr79Kjy">single-phase</a> circuit at the same line-to-ground <a href="/facts/Voltage/EN2po6N2">voltage</a> because it uses less conductor material to transmit a given amount of electrical power. Three-phase power is mainly used directly to power large <a href="/facts/Induction_motors/DgTnMmJM">induction motors</a>, other <a href="/facts/Electric_motors/ArD7BGDa">electric motors</a> and other heavy loads. Small loads often use only a two-wire single-phase circuit, which may be derived from a three-phase system.

Three-phase electric power open-in-new

Three-phase electric power