Total 3-phase real power = sqrt(3) x VLL x ILL x cos (theta) = 3 x Vp x Ip x cos (theta)
Total 3-phase reactive power = sqrt(3) x VLL x ILL x sin (theta) = 3 x Vp x Ip x sin (theta)
where: ?LL denotes line-to-line and ?p denotes phase-to-ground quantities
Therefore, S = sqrt( P2+Q2) =
= sqrt[32 x Vp2 x Ip2 x cos2 (theta) + 32 x Vp2 x Ip2 x sin2 (theta)]
= sqrt[32 x Vp2 x Ip2 x {cos2 (theta) + sin2 (theta)}]
= sqrt[32 x Vp2 x Ip2 x {1}]
= 3 x Vp x Ip (works for the line-to-line case, as well)
Hope this helps,
Chris
For a three phase real power calculations we are using the formula:
P=Sqrt3*V*I*PF
PF:Power Factor =1 if the load is pure resistance like the light
V: Voltage
I: Current
Real power (W, watts) is apparent power (VA, volt-amperes), times power factor. Power factor is the cosine of the phase angle between voltage and current. For a resistive load, such as a toaster, power factor is unity, so W is VA. For an inductive load, such as a motor, with a (typical) power factor of 0.92, W is VA times 0.92.
Also, in terms of reactive power, real power (W) is reactive power (VAR) times the reactive power factor, which is the sine of the phase angle between voltage and current.
To clarify "true", "apparent", and "reactive" power, the phasor sum of VA and VAR is equal to W. Think of the unit circle, where zero degrees is resistive, generally shown as north. For the example case of the inductive load at 0.92 power factor, the angle of the phase angle is -23 degrees, or typically shown as 337 degrees. VA in this case, if W equals 10000, is 9200, while VAR is -3919.
Phase has nothing to do with the equation, since you need to consider each phase on its own merits, and add up the results. However, do not forget that you need to be consistent, in that you always use star or delta voltage. If you switch systems, star to delta or delta to star, don't forget the 1.732 (square root of 3) factor in the calculations.
Apparent power is a function of power factor, true power over apparent gives you the power factor.
All items of current using equipment have losses
you may have a motor that claims a power of 1000w but actually reads as 1150w
1000/1150 =0.86 (a poor power factor)
AnswerApparent power (expressed in volt amperes) for a three-phase load is exactly the same as for a single-phase load in that it is the vectorial sum of the true power (expressed in watts) and the reactive power (expressed in reactive volt amperes). For a balanced load, it can be determined from the equation: 1.732 x Vline x Iline. For an unbalanced load, it is more complicated to calculate, as you will need to determine the apparent power per load.
The general equation for apparent power in a balanced three-phase load is as follows:
Apparent Power = 1.732 VL IL (where L = line values)
This will tell you what the transformer is delivering. If you want to know what the transformer's rating is, then you'll need to know the transformer's rated secondary line voltages and currents, and substitute these values into the above equation.
Kw
For Single Phase, P = VI cos (theta) therefore cos(theta) = P/VI here P = Power V = voltage I = current theta = phase angle current to voltage cos(theta) = power factor For Three Phase, P = 3VI cos(theta) where V = phase voltage and I = phase current and theta = phase angle
With no three phase power supply you can't use a three phase motor of any kind at all!
Electric power is measured in watts. It does not matter if it is single phase or three phase. All things being equal, for the same load, the power measured in a single phase circuit or a three phase circuit, will be the same.
Houses generally run on single phase power. It would not make sense to convert single phase to three phase to run a house. Please restate the question.
http://en.wikipedia.org/wiki/Three-phase_electric_power Click on this link from Wikipedia. It gives an excellent description of three phase power.
You will need to determine the power per phase, and add them up to give the total power of the three-phase load. To do this, you will need to multiply the phase-voltage by the phase current by the power factor -for each phase.
Your question is rather vague. Are you asking how do you determine the reactive power of a capacitor bank necessary to improve the power factor of a load (in which case, is it a single-phase or a three-phase load), or are you asking how to convert a capacitor bank's capacitance into reactive power?If the former, then you need to know the reactive power of the load before power factor-improvement, and the resulting reactive power after power-factor improvement, and the difference between these two will tell you how much reactive power you need to add in the form of capacitors.
For Single Phase, P = VI cos (theta) therefore cos(theta) = P/VI here P = Power V = voltage I = current theta = phase angle current to voltage cos(theta) = power factor For Three Phase, P = 3VI cos(theta) where V = phase voltage and I = phase current and theta = phase angle
With no three phase power supply you can't use a three phase motor of any kind at all!
You need three phase power to get three phase power. If you only have one phase, you will need some kind of inverter or motor-generator set. Generally, however, the demands of a three phase motor will exceed the capability and efficiency of these "tricky" solutions. It is best to simply contact your local power company and have them provide the proper three phase power to your facility.
Electric power is measured in watts. It does not matter if it is single phase or three phase. All things being equal, for the same load, the power measured in a single phase circuit or a three phase circuit, will be the same.
You don't. A three phase motor will not start unless it is connected to a three phase supply.
Three phase power is always delivering power on one of the phase continuously. This is very useful to manufacturing industries to operate the machines, which require high power utilization.
To use a single/one phase motor instead of a three phase motor is possible if you have a three phase power supply as you will only need to tap one of the three phases together with neutral and an earthwire, however to use a three phase motor instead of a single phase will require the provision of three phase power supply.
No. A three-phase ballast requires three-phase power
Houses generally run on single phase power. It would not make sense to convert single phase to three phase to run a house. Please restate the question.
Power = Current * Voltage * Power FactorAbove expression can further be explore as :1. For DC CircuitsPower = Current * Voltage2. For Single Phase AC CircuitPower = Current * Voltage * Power Factor3. For Three Phase AC CircuitPower = Line Current * Line Voltage * Power Factor