Quick question on 3 phase before my final

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SUMMARY

The discussion centers on the confusion regarding the angle in three-phase power equations, specifically in the context of the equations P=(VrmsIrms)cos(θ) and Q=(VrmsIrms)sin(θ). The angle in question is identified as the phase angle between voltage and current, which directly relates to the power factor (cosθ). For purely resistive loads, this angle is zero, resulting in a power factor of one and no reactive power (Q). The correct equation for power transmission in three-phase systems is clarified as P=√3(V)(I)cosθ.

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  • Understanding of three-phase power systems
  • Familiarity with electrical power equations
  • Knowledge of phase angles and power factors
  • Basic concepts of reactive and real power
NEXT STEPS
  • Study three-phase power calculations in depth
  • Learn about power factor correction techniques
  • Explore the implications of reactive power in electrical systems
  • Review the derivation of the equation P=√3(V)(I)cosθ
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Electrical engineering students, professionals working with power systems, and anyone seeking to deepen their understanding of three-phase power calculations.

tanky322
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Quick question on 3 phase before my final!

Homework Statement



In equations for 3 phase power there is an angle that is mentioned, but I don't know if this is the angle of the impedance or another angle. I am a little confused. The equations are below.



Homework Equations


P=(VrmsIrms)cos(\theta)
Q=(VrmsIrms)sin(\theta)


Any help?
 
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tanky322 said:

Homework Statement



In equations for 3 phase power there is an angle that is mentioned, but I don't know if this is the angle of the impedance or another angle. I am a little confused. The equations are below.



Homework Equations


P=(VrmsIrms)cos(\theta)
Q=(VrmsIrms)sin(\theta)


Any help?
I'm certainly not an electrical expert, but the angle you are referring to is the phase angle between the voltage and the current, where cos\theta = power factor. For purely resistive loads, theta is 0, hence the power factor is unity, and there is no reactive power Q. However, I don't quite understand your equation, since typically ,for power transmsission, P= \sqrt3(V)(I)cos\theta. That's about it for my electrical knowledge.
 

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