Calculating Equivalent Series Resistance and Inductance for Parallel Branches

In summary, the conversation discusses calculating the equivalent series resistance and inductance of two parallel branches. The question is whether the resistance and inductance can be calculated separately or if they must be combined. It is mentioned that using the second method, which involves converting to polar and back to rectangular, gives different answers compared to the first method. The question is answered with the second method being correct.
  • #1
Physicist3
104
0
Hi,

If I have two brances, branch 1 and branch 2 which are in parallel and each branch has a resistance and inductance, to calculate the equivalent series resistance and inductance, can I calculate the resistance and inductance separately e.g.

Req = R1*R2/R1+R2 (and same for X),

or do I have to do it combined E.g.

Zeq = (R1+jX1)*(R2+jX2)/(R1+jX1)+(R2+jX2), and then convert to polar etc and back to rectangular to find the equivalent R and jX values? The two methods give me different answers?

Sorry, forgot to add, the values of R and X are in PER UNIT
 
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  • #2
Physicist3 said:
The two methods give me different answers?
And the second one is correct. That should answer if the first one works.
Note that there are brackets missing.
 

Related to Calculating Equivalent Series Resistance and Inductance for Parallel Branches

What is the difference between parallel impedance and series impedance?

Parallel impedance refers to the total impedance of a circuit where components are connected in parallel, meaning the current has multiple paths to flow through. Series impedance, on the other hand, refers to the total impedance of a circuit where components are connected in series, meaning the current has only one path to flow through.

How are parallel impedance and series impedance calculated?

Parallel impedance is calculated using the formula Zp = 1 / (1/Z1 + 1/Z2 + ... + 1/Zn), where Z1, Z2, ... , Zn are the individual impedances of the components. Series impedance is calculated using the formula Zs = Z1 + Z2 + ... + Zn, where Z1, Z2, ... , Zn are the individual impedances of the components.

How do parallel and series impedances affect the overall impedance of a circuit?

In a parallel circuit, the total impedance is lower than the individual impedances of the components. This is because the current has multiple paths to flow through, reducing the overall resistance. In a series circuit, the total impedance is higher than the individual impedances of the components. This is because the current has only one path to flow through, increasing the overall resistance.

Can parallel and series impedances be combined in a circuit?

Yes, parallel and series impedances can be combined in a circuit. This is known as a combination circuit, where some components are connected in parallel and others in series. The overall impedance of a combination circuit is calculated by first calculating the parallel impedance of the parallel components, then adding this to the series impedance of the series components.

What are the advantages and disadvantages of using parallel and series impedances in a circuit?

The main advantage of using parallel impedances in a circuit is that it allows for a high current to flow through the circuit, making it suitable for applications that require a large amount of power. The main disadvantage is that it can be more complex to design and troubleshoot. On the other hand, series impedances have the advantage of being simpler to design and troubleshoot, but the disadvantage of limiting the current flow in the circuit.

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