What is Three phase power: Definition and 11 Discussions

Three-phase electric power is a common method of alternating current electric power generation, transmission, and distribution. It is a type of polyphase system and is the most common method used by electrical grids worldwide to transfer power. It is also used to power large motors and other heavy loads.
A three-wire three-phase circuit is usually more economical than an equivalent two-wire single-phase circuit at the same line to ground voltage because it uses less conductor material to transmit a given amount of electrical power.
Polyphase power systems were independently invented by Galileo Ferraris, Mikhail Dolivo-Dobrovolsky, Jonas Wenström, John Hopkinson and Nikola Tesla in the late 1880s.

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    Leakage Reactance of a three phase power transformer using Ansys Maxwell

    Hello all; I am trying to calculate leakage reactance of three phase power transformer . I am using Ansys Maxwell final element solution to analyse it. The software gives me total energy and linkages and self and mutual inductances.By using this quantities how can ı compute leankage reactances...
  2. Marcin H

    Three Phase WYE - DELTA Problem

    Homework Statement Homework Equations Power Triangle and 3-phase equations (listed in my solutions) The Attempt at a Solution Here are the instructor solutions: The instructor solutions just go straight into using equations, but I like to use the power triangle because it is more...
  3. T

    Three phase power meaurement questions

    I have a few questions regarding three phase power measurement Three Watt-meter method: Balanced load: What would happen if the neutral where removed ?, my guess is that it wouldn't make a difference because the neutral doesn't carry any current Unbalanced load: Same question as above Two...
  4. G

    How to Determine Capacitance for Active Power in a Three-Phase System?

    Homework Statement In the given AC circuit, electromotive forces form a symmetric and direct three-phase system. Angular frequency \omega, magnitudes U_{AB},U_{BC},U_{CA}=U, resistance R, inductance L and coefficient of inductive coupling k\neq 1 are given. Find capacitance C such that the...
  5. G

    Active power of three-phase system

    Homework Statement Find active power of the given three-phase system. U_{RS}=U_{ST}=U_{TR}=220\sqrt 3 V R=\omega L=\frac{1}{\omega C}=10\Omega 2. The attempt at a solution After reducing the circuit to one phase (see attachments), equivalent impedance is...
  6. Y

    Engineering Electrical Circuits - Three Phase Power - Y-Y transformer

    Homework Statement I took a few pictures of the circuit, it went across two pages so I took a few pictures, and closeups of certain parts to ensure that all the details can be seen For the circuit: http://s7.postimg.org/ywd4nrmsq/IMG_20150905_140403187_HDR.jpg Figure 1. Overview of Circuit...
  7. B

    How to Safely Wire a Chain Hoist for 480V Operation - Tips and Instructions

    Hi, I have a chain hoist that I am trying to wire so that it'll run off of 480V. The pictures below show the hoist/motor's technical specs, and what type of system it is. So now my question is this. How do I wire a plug for this system, so that I can run it? What plug type will I need...
  8. K

    Required current rating of 3-phase power system

    My background is mechanical engineering so not great with the electrical side. I plan on buying a air-preheater (resistive wire heated) which has a power rating of 30kW, supplied by 3-phase. I need to determine whether my 3-phase supply (415V 32A) has a max current that can cope with this. My...
  9. C

    Can These Power Supplies Handle a 30/60V, 120A Load Continuously?

    Hi guys, I have few questions here regarding power supplies. I have two models of power supplies and from the data sheet of the power supplies. and I would like to enquiry on one of the model. If i have to feed the load(Panel switchgear) fully 30/60V DC, 120Amp continuously for several hours...
  10. J

    Calculating Three Phase Power for an Asynchronous Motor-Generator

    Hi We are measuring 3 Phase Power of an asynchronous Motor-Generator and have equipment installed on Phase 1 (L1) and Phase 3 (L3) to measure the current/voltage/power. I have some questions regarding the results. Q) Why is the Power of Phase 1 positive and Phase 3 Negative ? Q) How can...
  11. S

    Is 3 Phase Power Essential for a Complete Education in Electrical Engineering?

    Hello, I am an Electrical Engineering student taking my second circuit analysis course. My program is actually very good and they explain things very well. My main concern is that none of my courses have covered or much less mentioned 3 phase power. My first question is simple: Are they skimping...