Circuit Impedance Calculation

[lj]

I am attempting to calculate the total line-to-neutral impedance, Ztotal, of two circuits in series. Ckt 1 is from a 480/277V main switchboard to a panelboard, and Ckt 2 is from the panelboard to a 3-phase load having a power factor = 0.89. Ckt 1 impedance is Z1, and ckt 2 impedance is Z2.
Question 1: How do I find Ztotal? Is it Z1+Z2, or SQRT (Z1^2 + Z2^2), or some other value?
Question 2: Is Zline-to-line = Zline-to-neutral x 1.73? Thank you greatly.

 

[zog]

I am attempting to calculate the total line-to-neutral impedance, Ztotal, of two circuits in series. Ckt 1 is from a 480/277V main switchboard to a panelboard, and Ckt 2 is from the panelboard to a 3-phase load having a power factor = 0.89. Ckt 1 impedance is Z1, and ckt 2 impedance is Z2.
Question 1: How do I find Ztotal? Is it Z1+Z2, or SQRT (Z1^2 + Z2^2), or some other value?
Question 2: Is Zline-to-line = Zline-to-neutral x 1.73? Thank you greatly.

Sounds like a homework question to me.

 

[lj]

Circuit Impedance Calculation

It does look that way. Actually, it is real, although I have simplified it to eliminate what I think is unimportant. It seems easier to find voltage drop using tables; the correct formulas for just impedance is a different problem. Thanks.

 

[SAC]

Calculating the total effective impedance of impedances in series is the sum of the individual series impedances.

Calculating the total effective impedance of impedances in parallel is the reciprocal of the sum of the reciprocals of the individual impedances.

 

[SAC]

For number 2 - probably not (draw the circuit diagram and figure it out).

 

[lj]

Circuit Impedance Calculation

SAC, I appreciate your very clear answer to Q1. For Q2, the circuit diagram would lead me to believe that Z(L-L) = 2 x Z(L-N), since the two conductors would be in series. I'll have to think about this further. Thanks.