Calculate Inductance of Inductor: 100v/20A RMS

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Discussion Overview

The discussion revolves around calculating the inductance of an inductor in a circuit where a non-inductive resistor is connected in series with the inductor. Participants explore the relationship between voltage, current, impedance, and reactance in the context of AC circuits, specifically focusing on a scenario involving a 100V RMS supply and a 230V supply with given current values.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • One participant calculates the resistance (R) as 5 ohms based on the given voltage and current for the non-inductive resistor.
  • Another participant derives the impedance (Z) of the circuit as 15.3 ohms using the formula Z = V/I with the 230V supply and 15A current.
  • There is a discussion on how to find the inductance (L) using the formula for reactance (X_L = 2πfL), with participants expressing uncertainty about the inductance calculation.
  • One participant suggests that the inductance could be 21.7 H, while another participant calculates it as 0.0458 H, leading to a discussion about the method used for the calculation.
  • Clarification is provided on the calculation of inductance using the reactance value derived earlier (X_L = 14.45 ohms) and the frequency (f = 50 Hz).
  • A participant acknowledges a substitution mistake in their earlier calculation, indicating a correction in their approach to finding L.

Areas of Agreement / Disagreement

Participants express differing values for the inductance, with one suggesting 21.7 H and another calculating it as 0.0458 H. The discussion remains unresolved regarding which value is correct, and there is no consensus on the final inductance value.

Contextual Notes

Participants rely on specific formulas and values, but there is no consensus on the correct inductance due to differing calculations and potential mistakes in substitution. The discussion highlights the need for careful application of formulas in AC circuit analysis.

johnboy14
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Homework Statement



a non inductive resistor passes a current of 20A rms, when connected to a 100v rms supply (50HZ). When connect in series with a pure inductor across a 230v supply the combination draws a current of 15A calculate impedance of the circuit, inductance of the inductor





The Attempt at a Solution



R = 100v/20A = 5 ohms

Z = V/I

Z = 230/15 = 15.3

z = square root R^2 + X^2 Find X^2

Z^2 - R^2 = X^2

SRoot 15.3^2 - 5^2 = 14.45 ohms

From what I found how do I find the inductance of the inductor. I only know one way using flux density but there is no data given on this in the question.
 
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I know that the formula for reactance is Xl = 2(pi) f L
How do I find L that's the just of what I want.
 
johnboy14 said:
I know that the formula for reactance is Xl = 2(pi) f L
How do I find L that's the just of what I want.

You know that X_L = 14.45\Omega anf f = 50Hz.
 
Do yous get 21.7 for L
 
johnboy14 said:
Do yous get 21.7 for L

I found 0.0458H
 
SGT said:
I found 0.0458H

How did you get that
 
johnboy14 said:
How did you get that

L=\frac{X_L}{2\pi\,50}=\frac{14.45}{314.16}=0.0458H
 
I see I made a substitution mistake in my formula I devided by XL thanks for the help
 

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