What is Three phase: Definition and 82 Discussions

In electrical engineering, three-phase electric power systems have at least three conductors carrying alternating voltages that are offset in time by one-third of the period. A three-phase system may be arranged in delta (∆) or star (Y) (also denoted as wye in some areas). A wye system allows the use of two different voltages from all three phases, such as a 230/400 V system which provides 230 V between the neutral (centre hub) and any one of the phases, and 400 V across any two phases. A delta system arrangement only provides one voltage, but it has a greater redundancy as it may continue to operate normally with one of the three supply windings offline, albeit at 57.7% of total capacity. Harmonic current in the neutral may become very large if nonlinear loads are connected.

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  1. I

    Overheating of Three phase Induction motor

    Dear friends, 3 phase ind motor is overheated and also tripped during operation. The heat over the induction motor is extremely hot. What will be the reason? Is it due to coil damage inside of motor.? Kindly reply, thank you!
  2. S

    Why we are using single phase & three phase

    Why we are using Three phase & single phase instead of using two phase , four phase, five phase.
  3. B

    Question about single phase to three phase conversion

    What type of circuit can convert single phase electric power into three phase electric power? Can the circuit diagram be posted in this thread?
  4. S

    Can Capacitors Create Specific Phase Shifts in DIY Three-Phase AC Systems?

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  5. B

    Electromagnetic forces in Three Phase Copper Busbars (Rectangular)

    Homework Statement So here is the Problem : I am Modelling an interesting problem for a project i am busy with. I need to find out the force exerted on a single busbar in a 3 phase system, with each phase carrying 3300A. This is mainly so that i can deduce what size of busbar supports i...
  6. J

    How to calculate the slip in an three phase induction motor

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  7. S

    Engineering Total power factor, 1 motor, three phase, two loads

    Homework Statement A balanced three phase Y-connected source has a line voltage of 208V and feeds two balanced Y-connected loads. The per-phase impedances of the two loads are 20+j70 and 50+j30 ohms respectively. Calculate the power supplied to each load by the source. What is the power factor...
  8. K

    Three Phase pi-section model of power system transmission lines

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  9. S

    Is My Three Phase Meter Giving Accurate Measurements?

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  10. C

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  11. J

    Calculating Three Phase Power for an Asynchronous Motor-Generator

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  12. J

    Three phase system phasor diagram

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  13. PhanthomJay

    Three Phase to Phase Voltage between different circuits

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  14. R

    Three Phase Troubleshooting: Calculating Voltage & Current

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  15. S

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

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  16. D

    Three phase induction generator on a single phase supply

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  17. D

    How is the Square Root of Three Factor Derived in a Three Phase Generator?

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  18. F

    Three Phase A.C Supply: Explained

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  19. R

    Electricity Rates in India: Single and Three Phase Lines

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  20. N

    Three-Phase System: RMS Phase Voltage Magnitude 230V, Zg=5+j5, 30+j30 Loads

    Homework Statement consider the balanced three phase star source with RMS phase voltage magnitude of 230V shown in fig5 with an impedance of Zg=5+j5.The per-phase impedance value of a three phase balanced star and delta connected loads are 30+j30. a)Determine the line and phase voltages and...
  21. M

    Multi-Phase or more then three phase

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  22. M

    Three phase ac motors 110v help

    I have a motor i am trying to get to work. The tag on it says its a three phase asynchronous motor. 110v and i think the current is 6.9amps. When i turn it on it hums and if i spin the motor it will start to go and will spin very slowly but as soon as any resistance is applied it stops and just...
  23. E

    What Is the Output Voltage Waveform of a 3-Phase Half-Wave Rectifier?

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  24. B

    Is My Calculation of Phase and Line Currents in a Delta Circuit Correct?

    Homework Statement Three impedance of 10+j6 are delta connected to a three phase 208 V power line. I am to find The Phase currents, and Line currents. I am just learning this so bear with me please. I am correct to assume that the voltage across each impedance is the source voltage of...
  25. B

    Engineering Calculating Phase and Line Currents in a Three Phase Delta Circuit

    Homework Statement Three impedance of 10+j6 are delta connected to a three phase 208 V power line. I am to find The Phase currents, and Line currents. I am just learning this so bear with me please. I am correct to assume that the voltage across each impedance is the source voltage of...
  26. L

    How Does Cable Size Affect Voltage Drop in Three-Phase Systems?

    I was just looking for some insight on this problem. It is not a homework problem, my boss just asked me to figure it out. Now, there is 120V supply, with 600 feet of cable (copper) running to a load, and 600 ft neutral coming back to the supply. Ignoring the resistance of the load, he asked...
  27. A

    How Efficient and Effective Are Typical Three Phase Induction Motors?

    hey does anyone know the effiency and power factor of a typical three phase induction motor? cheers,
  28. S

    How can I accurately find the line currents in a Wye-Delta three phase circuit?

    Hi, In the attached file, the question asks to find the three line currents. I understand the solution using Mesh Analysis that was used. However, I am unsure as to why when I convert the Delta Load to a Wye load, I get the wrong answer. Using Zwye = (1/3)Zdelta, adding the series line...
  29. S

    Engineering Solving for Line Currents in a Wye-Delta Circuit

    Hi, In the attached file, the question asks to find the three line currents. I understand the solution using Mesh Analysis that was used. However, I am unsure as to why when I convert the Delta Load to a Wye load, I get the wrong answer. Using Zwye = (1/3)Zdelta, adding the series line...
  30. W

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  31. D

    Two Phase - Three Phase - Whats the scoop?

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  32. G

    What Are the Differences Between Single Phase and Three Phase Power?

    what are the major different other than the reason why you do three phase for motor and advantages. In detail in wiring why do you have 4 lines in three phase goig into three terminal and 4 lines goign into two termnial in single phases? what is the best way to give a summary to a person who...
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