Problem about Sinusoidal Circuits

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Discussion Overview

The discussion revolves around a homework problem related to sinusoidal circuits, specifically focusing on calculating the source voltage, power loss in a feeder, and the necessary capacitor size to improve power factor. The scope includes technical reasoning and mathematical calculations associated with electrical engineering concepts.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • One participant presents a problem involving a 60 Hz system with specific power requirements and asks for help in calculating various parameters related to the feeder and load.
  • Another participant suggests drawing a circuit that includes the feeder impedance to clarify the relationship between the load voltage and the source voltage, indicating that the ideal voltage source is likely higher than 120 volts.
  • A participant expresses ongoing difficulties in solving the problem and requests assistance, emphasizing a time constraint for submission.
  • One participant comments on the desire to see the thread completed, regardless of the homework deadline.

Areas of Agreement / Disagreement

The discussion remains unresolved with participants expressing varying levels of understanding and assistance. There is no consensus on the solution to the problem, and multiple viewpoints on how to approach it are present.

Contextual Notes

Participants have not fully explored the implications of the feeder impedance on the calculations, and there may be missing assumptions regarding the ideal voltage source and its relationship to the load voltage.

Who May Find This Useful

Students studying electrical engineering, particularly those focusing on circuit analysis and power systems, may find this discussion relevant.

BRAWNY
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hey everybody
how are you ?
hope everyone's fine
well , i have this problem related to electrical circuits

Homework Statement



A group of small appliances on a 60 Hz system requires 20kVA at 0.85 pf
lagging when operated at 120 V (rms). The impedance of the feeder
supplying the appliances is 0.01 + j0.08Ω. The voltage at the load end of
the feeder is 120 V.

Homework Equations



1. What is the rms magnitude of the voltage at the source end of the feeder?
2. What is the average power loss in the feeder?
3. What size capacitor (in microfarads) at the load end of the feeder is
needed to improve the load power factor to unity?
4. After the capacitor is installed, what is the rms magnitude of the voltage
at the source end of the feeder if the load voltage is maintainedDW V?
5. What is the average power loss in the feeder for part (d)?

The Attempt at a Solution


well , since the problem gives us the complex power (20000 VA ) and the Voltage , i can get the conjugate current which equals to 166,6 and the phase angle i can get it from the power factor (0.8) .. that is what i know ..
please if you can help me out here i will be appreciated
 
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Draw a circuit which includes the feeder impedance since the power factor and voltage are given at this point, not at the ideal generator.

If you don't see why this is needed, let me say that the ideal voltage source is slightly higher than 120 volts. If it's not obvious why, then you need the schematic.
 
i still have problems how to solve it

any help
i have to submit it tomorrow >> please help me out
 
It would be nice to see this thread completed, even if the homework is already past due.
 

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